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evolution
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the enzyme belongs to the GH16 XTH family, extension clan GH-B enzymes
evolution
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the enzyme belongs to the GH16 XTH family, gene models, overview
evolution
the enzyme belongs to glycosyl hydrolase family 16, which play an important role in endosperm weakening and embryonic expansion during seed germination by loosening the micropylar endosperm and also improving the embryo expansion
evolution
Q40144, Q43527, Q43528, Q6RHX7, Q6RHX8, Q6RHX9, Q6RHY0, Q6RHY1, Q9FR51, Q9FZ05, Q9SLN9 XTHs genes belong to a multi-genetic family, phylogenetic analysis
evolution
C0IRH4, C0IRH6, C0IRH7, C0IRH8, C0IRH9, C0IRI0, C0IRI1, C0IRI2, C0IRI3, C0IRI4, Q8GTJ0 XTHs genes belong to a multi-genetic family, phylogenetic analysis
evolution
Petroselinum sp.
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xyloglucan endotransglucosylase (XET) is a homotransglycanase enzyme activity found in all land plants and in some charophytic algae
evolution
xyloglucan endotransglucosylase/hydrolases (XTHs) are encoded in Arabidopsis by a 33-member gene family, isozyme XTH15 is a classical group-I/II XTH
evolution
xyloglucan endotransglucosylase/hydrolases (XTHs) are encoded in Arabidopsis by a 33-member gene family, isozyme XTH31 is a group-III-A XTH
evolution
xyloglucan endotransglycosylase/hydrolase (XTH) enzymes belong to the glycosyl hydrolase family 16 (GH16) superfamily, phylogenetic analysis, gene PrXTH1 belongs to group I of XTHs
evolution
evolutionary relationship of persimmon DkXTH6 and DkXTH7 genes among other plant species and phylogenetic tree, overview. DkXTH6 and DkXTH7 possess several functional domains typical in plant XTHs, including the conserved amino acids (DEIDFEFLG) as a putative active site and together with a potential N-linked glycosylation (N-X-S/T) site
evolution
the XTH isozymes contain the conserved DEIDFEFLG motif identified as the catalytic domain of XTH
evolution
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endoglucanase family 16 members are identified in addition to XTHs of glycoside hydrolase family 16. Phylogenetic analysis clusters the XTHs into three major groups (group I/II, III and ancestral group), group III is subdivided into group IIIA and group IIIB. Similar gene structure and motif number are observed within a group. Two highly conserved domains, glycosyl hydrolase family 16 (GH16-XET) and xyloglucan endotransglycosylase C-terminus (C-XET), are detected by multiple sequences alignment of all XTHs. Segmental replication are detected in the two cultivars, with only the paralogous pair Ac(F153)XTH7-Ac(F153)XTH18 presented in F153 prior to genomic expansion. Genome-wide analysis. Ka/Ks analysis and estimated divergence time of XTHs, detailed phylogenetic analysis and evolutionary relationships, overview
evolution
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endoglucanase family 16 members are identified in addition to XTHs of glycoside hydrolase family 16. Phylogenetic analysis clusters the XTHs into three major groups (group I/II, III and ancestral group), group III is subdivided into group IIIA and group IIIB. Similar gene structure and motif number are observed within a group. Two highly conserved domains, glycosyl hydrolase family 16 (GH16-XET) and xyloglucan endotransglycosylase C-terminus (C-XET), are detected by multiple sequences alignment of all XTHs. Segmental replication are detected in the two cultivars, with only the paralogous pair Ac(F153)XTH7-Ac(F153)XTH18 presented in F153 prior to genomic expansion. Ka/Ks analysis and estimated divergence time of XTHs, detailed phylogenetic analysis and evolutionary relationships, overview
evolution
isozyme TmXET6.3 is a membrer of the GH16 family
evolution
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phylogenetic analysis of the nucleotide sequences of the open reading frames of the XTHs genes of Arabidopsis thaliana and poplar PnXTH1 shows that this gene is the closest to genes AtXTH5 (endoxyloglucan transferase A4, EXGT-A4) and AtXTH4 (endoxyloglucan transferase A1, EXGT-A1). Identification and analysis of the cis-regulatory elements of the putative promoter region of PnXTH1 gene orthologue from Populus trichocarpa PtXTH1
evolution
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phylogenetic analysis shows that 24 HvXTH genes can be classified into three phylogenetic groups: (I/II, III-A and III-B) and HvXTH15 is in the ancestral group. Xyloglucan endotransglucosylase/hydrolases (XET/XEHs also named XTHs) are a family of xyloglucan modifying enzymes that have two different catalytic activities and can act either as endotransglucosylases (XET, EC 2.4.1.207) or as endohydrolases (XEH, EC 3.2.1.151). XTHs belong to glycoside hydrolase family 16. Each XTH possesses a highly conserved domain (ExDxE) responsible for catalytic activity. Four gene pairs (HvXTH6/7, HvXTH17/18, HvXTH19/20, HvXTH21/22) are detected within 100 kb on chromosome 3H and chromosome 7H, which may be the result of tandem duplication. According to the phylogenetic tree, HvXTH6 and HvXTH7 and HvXTH17/18/19/20 are closely related, which indicates that the gene duplications of these three pair of genes might be related. The active site (ExDxE) containing the residues responsible for catalytic activity is highly conserved in all of the HvXTH family members. The first glutamate residue acts as catalytic nucleophile which initiates the enzymatic reaction and the second one as a base to activate the substrate
evolution
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XTHs are classified together with the lichenases, which hydrolyse mixed-linkage (1->3,1->4)-beta-D-glucans (MLG), in glycoside hydrolase family 16
evolution
xyloglucan endotransglycosylase/hydrolase (XTH) belongs to the GH16 subfamily of the glycoside hydrolases of carbohydrate active enzymes. 11 members of the XTH gene family are cloned from Populus tomentosa. A bioinformatics analysis reveals that the 11 PtoXTHs can be classified into three groups. Biochemical analyses of purified PtoXTHs demonstrate that only isozymes PtoXTH27 and PtoXTH34 have detectable xyloglucan endotransglucosylase (XET) activity, while the others do not exhibit XET or XEH activity. PtoXTH34 has a higher affinity for the receptor substrate implying that PtoXTH34 and PtoXTH27 in plants have different substrate structure specificity. Members of the XTH gene family may have one or two enzymatic activities: one is xyloglucan endohydrolase (XEH) activity, which specifically hydrolyzes xyloglucan beta-1,4 glycosidic bonds, and the other is xyloglucan endotransglucosylase (XET) activity, which refers to the transfer of xyloglucan fragments between xyloglucan molecules
evolution
xyloglucan endotransglycosylase/hydrolase (XTH) enzymes hold transglycosylase (XET), hydrolase (XEH), or both activities
malfunction
mutant seedlings defective in XTH15 exhibit no visible growth defects possibly because isozyme XTH16 closely resembles XTH15 in sequence, pI and expression profile
malfunction
overexpression of DkXTH8 results in increased leaf senescence coupled with higher electrolyte leakage in Arabidopsis and faster fruit ripening and softening rates in tomato. Transgenic plants overexpressing DkXTH8 display more irregular and twisted cells due to cell wall restructuring, resulting in wider interstitial spaces with less compact cells. DkXTH8 expression causes cells to be easily destroyed, increases membrane permeability and cell peroxidation, and accelerates leaf senescence and fruit softening in transgenic plants
malfunction
compared to the wild-type enzyme, the single Q108R and K237T, and double-K234T/K237T and triple-H94Q/A104D/Q108R variants exhibit enhanced heterotransglycosylation activities with xyloglucan and (1,4)-beta-D-glucooligosaccharides, while those with (1,3/1,4)- and (1,6)-beta D-glucooligosaccharides are suppressed, the incorporation of xyloglucan to (1,4)-beta-D-glucooligosaccharides by the H94Q variant is influenced most extensively. Physiological effects, overview
malfunction
loss-of-function of XTH30 leads to increased salt tolerance and overexpression of XTH30 results in salt hypersensitivity. Loss-of-function of XTH30 slows down the decrease of crystalline cellulose content and the depolymerization of microtubules caused by salt stress. Lower Na+ accumulation in shoot and lower H2O2 content are found in xth30 mutants in response to salt stress. The xth30 mutants wilt less and show a much higher survival rate than the wild-type under 125 mM NaCl treatment. XTH30 affects the xyloglucan oligosaccharide composition during salt stress
malfunction
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the constitutive expression of PnXTH1 in transgenic Nicotiana tabacum promotes an increase in the fresh and dry weight of the aboveground part of the plants mainly due to stimulation of leaf growth. Moreover, the degree of morphological changes in transgenic plants correlate with the expression level of PnXTH1. The root length increases substantially with the action of salt in all transgenic plants
malfunction
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loss-of-function of XTH30 leads to increased salt tolerance and overexpression of XTH30 results in salt hypersensitivity. Loss-of-function of XTH30 slows down the decrease of crystalline cellulose content and the depolymerization of microtubules caused by salt stress. Lower Na+ accumulation in shoot and lower H2O2 content are found in xth30 mutants in response to salt stress. The xth30 mutants wilt less and show a much higher survival rate than the wild-type under 125 mM NaCl treatment. XTH30 affects the xyloglucan oligosaccharide composition during salt stress
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metabolism
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enzymes FvXTH9 and FvXTH6 display xyloglucan endotransglucosylase (XET, EC 2.4.1.207) activity towards various acceptor substrates using xyloglucan as the donor substrate. FvXTH9 also shows activity of mixed-linkage glucan:xyloglucan endotransglucosylase (MXE) and cellulose:xyloglucan endotransglucosylase (CXE)
metabolism
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enzymes FvXTH9 and FvXTH6 display xyloglucan endotransglucosylase (XET, EC 2.4.1.207) activity towards various acceptor substrates using xyloglucan as the donor substrate. FvXTH9 also shows activity of mixed-linkage glucan:xyloglucan endotransglucosylase (MXE) and cellulose:xyloglucan endotransglucosylase (CXE). XTHs (xyloglucan endotransglucosylases/hydrolases) can catalyse the endolytic cleavage of xyloglucan polymers and the rejoining of the newly generated reducing ends to other xyloglucan molecules, which is referred to as xyloglucan endotransglucosylase (XET) activity. In addition, XTHs can also show xyloglucan endohydrolase (XEH) activity, where water is used as an acceptor, and thus the xyloglucan molecule is hydrolysed
metabolism
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the plant cell wall is a cellular exoskeleton consisting predominantly of a complex polysaccharide network that defines the shape of cells. During growth, this network can be loosened through the action of xyloglucan endotransglycosylases (XETs), glycoside hydrolases that cut and paste xyloglucan polysaccharides through a transglycosylation process
metabolism
the plant cell wall is a cellular exoskeleton consisting predominantly of a complex polysaccharide network that defines the shape of cells. During growth, this network can be loosened through the action of xyloglucan endotransglycosylases (XETs), glycoside hydrolases that cut and paste xyloglucan polysaccharides through a transglycosylation process
metabolism
typically, several XET isoforms operate during plant development or in response to environmental stimuli, consequently the expression of XTH genes needs to be regulated
physiological function
XTH28 is specifically involved in the growth of stamen fi laments, and is required for successful automatic self-pollination in certain flowers in Arabidopsis thaliana
physiological function
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xyloglucan endo-transglucosylase can link different polysaccharides in vivo and hence influence cell wall strength, flexibility, and porosity
physiological function
DcXTH2 is associated with petal growth and development during carnation flower opening
physiological function
DcXTH3 is associated with petal growth and development during carnation flower opening
physiological function
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plant cell wall extensibility is mediated, in part, by xyloglucan endotransglycosylases/hydrolases, XTH, that are able to cleave and reattach xyloglucan polymers that make up the hemicelluloses matrix of type I cell walls. The three GhXTH genes are expressed differently with GhXTH1 predominantly expressed in elongating cotton fibers, function of GhXTH1 in mediating cotton fiber elongation, the 35S::GhXTH1 transgene acts as a dominant fiber length allele in transgenic cotton, overview
physiological function
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xyloglucan endo-transglycosylases, XETs, encoded by xyloglucan endo-transglycosylases/hydrolase, XTH, genes modify the xyloglucan-cellulose framework of plant cell walls, thereby regulating their expansion and strength. Importance of XET in wood development, xyloglucan dynamics and XTH gene expression in developing wood, overview. Several XTH genes are involved in the development of secondary vascular tissues, XET activity stimulates cell expansion in vessel elements but not in fibers. In young xylem cells, XET activity limits xyloglucan incorporation into the tightly bound wall network but removes it from cell walls in older cells. Importance of XET activity for vascular tissue differentiation and/or function. Increased XET activity has differing effects on the xyloglucan content of expanding and maturing wood cells
physiological function
xyloglucan endotransglucosylase/hydrolases are cell wall enzymes that are able to graft xyloglucan chains to oligosaccharides or to other available xyloglucan chains and/or to hydrolyse xyloglucan chains. As they are involved in the modification of the load-bearing cell-wall components, they are believed to be very important in the regulation of growth and development
physiological function
xyloglucan endotransglucosylase/hydrolases are cell wall enzymes that are able to graft xyloglucan chains to oligosaccharides or to other available xyloglucan chains and/or to hydrolyse xyloglucan chains. As they are involved in the modification of the load-bearing cell-wall components, they are believed to be very important in the regulation of growth and development. AtXTH13 might play a role later in root hair development
physiological function
xyloglucan endotransglucosylase/hydrolases are cell wall enzymes that are able to graft xyloglucan chains to oligosaccharides or to other available xyloglucan chains and/or to hydrolyse xyloglucan chains. As they are involved in the modification of the load-bearing cell-wall components, they are believed to be very important in the regulation of growth and development. Role for AtXTH12 in root hair initiation. AtXTH13 might play a role later in root hair development
physiological function
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xyloglucan endotransglycosylase/hydrolases, XTH, are believed to play an important role in modifying the cell wall structure through two different, but related actions: the cleavage of a cross-linking xyloglucan polymer, xyloglucan endohydrolase or XEH activity, and transfer of a newly generated end to another sugar polymer, xyloglucan endotransglycosylase, XET, activity
physiological function
xyloglucan xyloglucosyl transferases modulate molecular masses of xyloglucans, size modulations and transfer reactions occur with polymeric acceptor substrates
physiological function
Q40144, Q43527, Q43528, Q6RHX7, Q6RHX8, Q6RHX9, Q6RHY0, Q6RHY1, Q9FR51, Q9FZ05, Q9SLN9 fruit undergoes extensive cell wall disassembly playing a major role in ripening-associated fruit softening. The changes in hemicellulosic polysaccharides are an important feature in the whole softening process. Xyloglucan endotransglycosylase/hydrolase enzymes play a key role in fruit ripening by loosening the cell wall through disassembly of xyloglucan. The ripening of climacteric fruits, such as tomato and apple, is controlled by endogenous ethylene biosynthesis. Ethylene causes a significant increase in activity in the ethylene treated fruits compared with the control fruits, in both tomato and apple fruits, suggesting an increase in the XTH gene expression induced by ethylene
physiological function
C0IRH4, C0IRH6, C0IRH7, C0IRH8, C0IRH9, C0IRI0, C0IRI1, C0IRI2, C0IRI3, C0IRI4, Q8GTJ0 fruit undergoes extensive cell wall disassembly playing a major role in ripening-associated fruit softening. The changes in hemicellulosic polysaccharides are an important feature in the whole softening process. Xyloglucan endotransglycosylase/hydrolase enzymes play a key role in fruit ripening by loosening the cell wall through disassembly of xyloglucan. The ripening of climacteric fruits, such as tomato and apple, is controlled by endogenous ethylene biosynthesis. Ethylene causes a significant increase in activity in the ethylene treated fruits compared with the control fruits, in both tomato and apple fruits, suggesting an increase in the XTH gene expression induced by ethylene
physiological function
Q40144, Q43527, Q43528, Q6RHX7, Q6RHX8, Q6RHX9, Q6RHY0, Q6RHY1, Q9FR51, Q9FZ05, Q9SLN9 fruit undergoes extensive cell wall disassembly playing a major role in ripening-associated fruit softening. The changes in hemicellulosic polysaccharides are an important feature in the whole softening process. Xyloglucan endotransglycosylase/hydrolase enzymes play a key role in fruit ripening by loosening the cell wall through disassembly of xyloglucan. t´The ripening of climacteric fruits, such as tomato and apple, is controlled by endogenous ethylene biosynthesis. Ethylene causes a significant increase in activity in the ethylene treated fruits compared with the control fruits, in both tomato and apple fruits, suggesting an increase in the XTH gene expression induced by ethylene
physiological function
gene PrXTH1 shows regulation by ethylene, indicating that it might be a target in the hormonal cascade during the inclination response
physiological function
isozyme XTH15 is predominantly expressed in early-stage organs, and thus seem likely to participate in cell expansion
physiological function
isozyme XTH31 is predominantly expressed in early-stage organs, and thus seem likely to participate in cell expansion. XTH31 is responsible for a specific mode of cell elongation that is particularly Al3+-sensitive. In the wild-type, a second mode of cell expansion that is more Al3+-resistant must be occurring simultaneously
physiological function
the enzyme regulates seed germination in Podophyllum by supplementing its activity along with other endosperm weakening and embryo expansion genes. Increased expression of PhXET influences seed germination in Podophyllum
physiological function
the primary cell wall of flowering plants consists of cellulose fibrils tethered by hemicelluloses (principally xyloglucans) and embedded in an amorphous matrix of pectins and glycoproteins. Plant cell expansion is mainly regulated by cell wall extensibility and results from selective loosening and rearrangement of the load-bearing cellulose/xyloglucan network, at least in flowering plants with type I cell walls where xyloglucan is a predominant hemicellulose. Xyloglucan endotransglucosylase/hydrolases (XTHs), a class of cell wall-modifying proteins, also have the capacity to loosen cell walls. Most XTHs cut and rejoin xyloglucan by xyloglucan endotransglucosylase, EC 2.4.1.207, action, whereas some XTHs hydrolyse xyloglucan by xyloglucan hydrolase, XEH EC 3.2.1.151, action
physiological function
the primary cell wall of flowering plants consists of cellulose fibrils tethered by hemicelluloses (principally xyloglucans) and embedded in an amorphous matrix of pectins and glycoproteins. Plant cell expansion is mainly regulated by cell wall extensibility and results from selective loosening and rearrangement of the load-bearing cellulose/xyloglucan network, at least in flowering plants with type I cell walls where xyloglucan is a predominant hemicellulose. Xyloglucan endotransglucosylase/hydrolases (XTHs), a class of cell wall-modifying proteins, also have the capacity to loosen cell walls. Most XTHs cut and rejoin xyloglucan by xyloglucan endotransglucosylase, EC 2.4.1.207, action, whereas some XTHs hydrolyse xyloglucan by xyloglucan hydrolase, XEH EC 3.2.1.151, action
physiological function
the primary cell wall of flowering plants consists of cellulose fibrils tethered by hemicelluloses (principally xyloglucans) and embedded in an amorphous matrix of pectins and glycoproteins. Plant cell expansion is mainly regulated by cell wall extensibility and results from selective loosening and rearrangement of the load-bearing cellulose/xyloglucan network, at least in flowering plants with type I cell walls where xyloglucan is a predominantchemicellulose. Xyloglucan endotransglucosylase/hydrolases (XTHs), a class of cell wall-modifying proteins, also have the capacity to loosen cell walls. Most XTHs cut and rejoin xyloglucan by xyloglucan endotransglucosylase, EC 2.4.1.207, action, whereas some XTHs hydrolyse xyloglucan by xyloglucan hydrolase, XEH EC 3.2.1.151, action
physiological function
xyloglucan endotransglycosylase/hydrolase enzymes plays a role in the remodeling of cell wall hemicelluloses. Function of isozymes in persimmon fruit development and postharvest softening. DkXTH isozymes function by targeting to the cell wall under regulation of a signal peptide
physiological function
a role for enzyme XTH31 in acid growth. Isozymes XTH15 and XTH31 are both strongly expressed in young, rapidly growing organs, suggesting that they play roles in cell expansion. In vitro, XTH15 has very high transglucanase (endotransglucosylase, XET) but undetectable hydrolytic activity (glucanase, XEH). In contrast, XTH31 has very high XEH activity and only slight XET activity
physiological function
fruit softening is mainly associated with cell wall structural modifications, and members of the xyloglucan endotransglucosylase/hydrolase (XTH) family are key enzymes involved in cleaving and rejoining xyloglucan in the cell wall. Isozyme DkXTH8, a xyloglucan endotransglucosylase/hydrolase in persimmon, alters cell wall structure and promotes leaf senescence and fruit postharvest softening
physiological function
isozymes XTH15 and XTH31 are both strongly expressed in young, rapidly growing organs, suggesting that they play roles in cell expansion. In vitro, XTH15 has very high transglucanase (endotransglucosylase, XET) but undetectable hydrolytic activity (glucanase, XEH). In contrast, XTH31 has very high XEH activity and only slight XET activity
physiological function
several XTH isozymes function in persimmon (Diospyros kaki) fruit development and postharvest softening. Isozymes DkXTH1, DkXTH4, and DkXTH5 expressions peak in immature expanding fruit, and their higher expression is observed along with higher fruit firmness in cold-treated fruit or firmer cultivar fruit during storage. The opposite gene expression patterns are observed in DkXTH2 and DkXTH3, which reach maxima concomitance with pronounced fruit softening. Meanwhile, the xyloglucan endotransglycosylase (XET, EC 2.4.1.207) enzymes play important roles in both the rapid growth and ripening of persimmon fruit. Furthermore, the recombined DkXTH1 and DkXTH2 proteins show significant XET activity without any detected XEH (EC 3.2.1.151) activity
physiological function
the holoparasitic angiosperm Cuscuta develops haustoria that enable it to feed on other plants, e.g. tomato plants. Cell wall modifications seem to be required in order for the parasite to successfully infect a host, changes to xyloglucan through the activity of xyloglucan endotransglucosylases/hydrolases (XTHs) are essential. On the other hand, XTH expression is also detected in resistant tomato upon an attack by Cuscuta, which suggests that both host and parasite use these enzymes in their arms race. Cell wall-modifying activities of XTHs during parasitization , overview. XTHs might function to make the host's resources accessible to Cuscuta. One of the defense responses of Solanum lycopersicum is the increased expression of LeXTH1, a gene encoding an XTH. The function of LeXTH1 might be to promote the elongation of tomato epidermal cells that takes place at the site of contact with the parasite. Another possibility is that LeXTH1 is deployed to reinforce the tomato cell walls, presumably as a remedy against the cell wall loosening activity of Cuscuta XTHs at the interface. Increased levels of xyloglucan degradation occur in the haustorium of Cuscuta reflexa and in the infected Solanum lycopersicum host plant
physiological function
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the holoparasitic angiosperm Cuscuta develops haustoria that enable it to feed on other plants, e.g. tomato plants. Cell wall modifications seem to be required in order for the parasite to successfully infect a host, changes to xyloglucan through the activity of xyloglucan endotransglucosylases/hydrolases (XTHs) are essential. On the other hand, XTH expression is also detected in resistant tomato upon an attack by Cuscuta, which suggests that both host and parasite use these enzymes in their arms race. Cell wall-modifying activities of XTHs during parasitization, overview. XTHs might function to make the host's resources accessible to Cuscuta. At the onset of haustorium development, the swelling of the parasite stem facing the host plant is facilitated by Cuscuta XTHs that promote expansive cell growth through wall loosening. As the haustorium begins its host-invasive growth, XTHs secreted from the infection organ aid tissue penetration by loosening host cell walls. Upon reaching the vascular bundles of its host, the cell wall loosening activity of Cuscuta XTHs at the host-parasite interface enables parasite feeding through apoplastic sugar transfer and/or by promoting vascular tissue differentiation. To prevent exaggerated cell wall loosening under low turgor pressure, Cuscuta XTHs must also strengthen its own walls. When Cuscuta attempts to invade cultivated tomato by deploying wall loosening XTHs at the interface, the counteractive wall strengthening activity of host-encoded XTHs prevents the haustorium from entering the host plant. Model of the putative function of XTHs in the parasitization strategy of Cuscuta, increased levels of xyloglucan degradation occur in the haustorium of Cuscuta reflexa and in the infected Solanum lycopersicum host plant
physiological function
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the holoparasitic angiosperm Cuscuta develops haustoria that enable it to feed on other plants. Cell wall modifications seem to be required in order for the parasite to successfully infect a host, e.g. Pelargonium zonale, changes to xyloglucan through the activity of xyloglucan endotransglucosylases/hydrolases (XTHs) are essential. In vivo colocalization of XET activity and donor substrate demonstrate XET activity at the border between host (petioles) and parasite, endotransglucosylation of xyloglucan at the host-parasite interface
physiological function
XTH, an important enzyme involved in xyloglucan metabolism, can function as a xyloglucan endotransglycosylase (XET, EC 2.4.1.207) and/or a xyloglucan endohydrolase (XEH, EC 3.2.1.151), with the former transferring one xyloglucan molecule fragment to another and the latter responsible for hydrolysis of one xyloglucan molecule. DkXTH7 is likely to be involved in cell wall assembly, special roles of isozyme XTH6 and XTH7 in persimmon fruit softening, overvie. The XTH gene family members each play a certain role in plant growth, fruit ripening, and fruit softening. During persimmon fruit postharvest softening,expression of isozymes DkXTH6 and DkXTH7 follows two opposing patterns
physiological function
XTH, an important enzyme involved in xyloglucan metabolism, can function as a xyloglucan endotransglycosylase (XET, EC 2.4.1.207) and/or a xyloglucan endohydrolase (XEH, EC 3.2.1.151), with the former transferring one xyloglucan molecule fragment to another and the latter responsible for hydrolysis of one xyloglucan molecule. Enzyme DkXTH6 might take part in cell wall restructuring, special roles of isozyme XTH6 and XTH7 in persimmon fruit softening, overview. The XTH gene family members each play a certain role in plant growth, fruit ripening, and fruit softening. During persimmon fruit postharvest softening,expression of isozymes DkXTH6 and DkXTH7 follows two opposing patterns
physiological function
xyloglucan endotransglucosylase (XET) activity, which cuts and re-joins hemicellulose chains in the plant cell wall, contributing to wall assembly and growth regulation, is the major activity of XTH proteins. During purification, XTHs often lose XET activity which, however, is restored by treatment with certain cold-water-extractable, heat-stable polymers (CHPs), e.g. from cauliflower florets
physiological function
xyloglucan endotransglucosylase (XET) activity, which cuts and re-joins hemicellulose chains in the plant cell wall, contributing to wall assembly and growth regulation, is the major activity of XTH proteins. During purification, XTHs often lose XET activity which, however, is restored by treatment with certain cold-water-extractable, heat-stable polymers (CHPs), e.g. from cauliflower florets
physiological function
xyloglucan endotransglucosylase (XET) activity, which cuts and re-joins hemicellulose chains in the plant cell wall, contributing to wall assembly and growth regulation, is the major activity of XTH proteins. During purification, XTHs often lose XET activity which, however, is restored by treatment with certain cold-water-extractable, heat-stable polymers (CHPs), e.g. from cauliflower florets, mung bean shoots, and Arabidopsis cell-suspension cultures
physiological function
enzyme FcXTH2 protein displays mainly xyloglucan hydrolase (XEH) activity and basal xyloglucan endotransglycosylase (XET) activity, and FcXTH2 is primarily a XEH. The enzyme is involved in the modification of the xyloglucans, a type of hemicellulose present in the cell wall. Possible role in strawberry development for enzyme FcXTH2
physiological function
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FvXTH6 might promote strawberry fruit ripening by the modification of cell wall components. The level of anthocyanins such as pelargonidin-3-O-glucoside and pelargonidin-3-O-(6'-malonyl)-glucoside is significantly higher in the infiltrated fruits, similar to citric acid and ascorbic acid
physiological function
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FvXTH9 and also FvXTH6 might promote strawberry fruit ripening by the modification of cell wall components. The level of anthocyanins such as pelargonidin-3-O-glucoside and pelargonidin-3-O-(6'-malonyl)-glucoside is significantly higher in the infiltrated fruits, similar to citric acid and ascorbic acid
physiological function
Populus xyloglucan endotransglycosylase/hydrolase (XTH) plays an important role in the structure and function of plant cell walls and is involved in osmotic stress responses
physiological function
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roles of HvXTH genes in the growth and development of barley, overview
physiological function
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the enzyme is involved in regulation of plant growth and stress resistance
physiological function
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the plant cell wall is a cellular exoskeleton consisting predominantly of a complex polysaccharide network that defines the shape of cells. During growth, this network can be loosened through the action of xyloglucan endotransglycosylases (XETs), glycoside hydrolases that cut and paste xyloglucan polysaccharides through a transglycosylation process
physiological function
the plant cell wall is a cellular exoskeleton consisting predominantly of a complex polysaccharide network that defines the shape of cells. During growth, this network can be loosened through the action of xyloglucan endotransglycosylases (XETs), glycoside hydrolases that cut and paste xyloglucan polysaccharides through a transglycosylation process
physiological function
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transcriptomic analysis indicates that XTHs are involved in the regulation of fruit ripening and crassulacean acid metabolism with tissue specificity, and quantitative real-time PCR expression analysis suggests that Ac(MD2)XTH18 is involved in root growth. XTH proteins perform two diverse catalytic activities: xyloglucan endohydrolase (XEH) and xyloglucan endotransglycosylase (XET)
physiological function
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transcriptomic analysis indicates that XTHs are involved in the regulation of fruit ripening and crassulacean acid metabolism with tissue specificity. XTH proteins perform two diverse catalytic activities: xyloglucan endohydrolase (XEH) and xyloglucan endotransglycosylase (XET)
physiological function
xyloglucan (XyG) is an important hemicellulose polymer of the primary cell wall in dicotyledons and non-commelinid monocotyledons. XyG plays a vital role in loosening or stiffening the cell wall by binding to cellulose microfibrils with hydrogen bonds during cell elongation. XyG chains can be cleaved or rejoined by xyloglucan endotransglucosylase-hydrolase (XTH). Alteration to the cell wall is one strategy that helps plants adapt to salt stress. Isozyme xyloglucan endotransglucosylase-hydrolase 30 (XTH30) negatively affects salt tolerance in Arabidopsis thaliana. XTH30 modulates XyG side chains, alters abundance of XLFG, cellulose synthesis, and cortical microtubule stability, and negatively affects salt tolerance. And XTH30 aggravates depolymerization of cortical microtubules under salt stress
physiological function
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plant cell wall extensibility is mediated, in part, by xyloglucan endotransglycosylases/hydrolases, XTH, that are able to cleave and reattach xyloglucan polymers that make up the hemicelluloses matrix of type I cell walls. The three GhXTH genes are expressed differently with GhXTH1 predominantly expressed in elongating cotton fibers, function of GhXTH1 in mediating cotton fiber elongation, the 35S::GhXTH1 transgene acts as a dominant fiber length allele in transgenic cotton, overview
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physiological function
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xyloglucan (XyG) is an important hemicellulose polymer of the primary cell wall in dicotyledons and non-commelinid monocotyledons. XyG plays a vital role in loosening or stiffening the cell wall by binding to cellulose microfibrils with hydrogen bonds during cell elongation. XyG chains can be cleaved or rejoined by xyloglucan endotransglucosylase-hydrolase (XTH). Alteration to the cell wall is one strategy that helps plants adapt to salt stress. Isozyme xyloglucan endotransglucosylase-hydrolase 30 (XTH30) negatively affects salt tolerance in Arabidopsis thaliana. XTH30 modulates XyG side chains, alters abundance of XLFG, cellulose synthesis, and cortical microtubule stability, and negatively affects salt tolerance. And XTH30 aggravates depolymerization of cortical microtubules under salt stress
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physiological function
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the primary cell wall of flowering plants consists of cellulose fibrils tethered by hemicelluloses (principally xyloglucans) and embedded in an amorphous matrix of pectins and glycoproteins. Plant cell expansion is mainly regulated by cell wall extensibility and results from selective loosening and rearrangement of the load-bearing cellulose/xyloglucan network, at least in flowering plants with type I cell walls where xyloglucan is a predominantchemicellulose. Xyloglucan endotransglucosylase/hydrolases (XTHs), a class of cell wall-modifying proteins, also have the capacity to loosen cell walls. Most XTHs cut and rejoin xyloglucan by xyloglucan endotransglucosylase, EC 2.4.1.207, action, whereas some XTHs hydrolyse xyloglucan by xyloglucan hydrolase, XEH EC 3.2.1.151, action
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physiological function
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the primary cell wall of flowering plants consists of cellulose fibrils tethered by hemicelluloses (principally xyloglucans) and embedded in an amorphous matrix of pectins and glycoproteins. Plant cell expansion is mainly regulated by cell wall extensibility and results from selective loosening and rearrangement of the load-bearing cellulose/xyloglucan network, at least in flowering plants with type I cell walls where xyloglucan is a predominant hemicellulose. Xyloglucan endotransglucosylase/hydrolases (XTHs), a class of cell wall-modifying proteins, also have the capacity to loosen cell walls. Most XTHs cut and rejoin xyloglucan by xyloglucan endotransglucosylase, EC 2.4.1.207, action, whereas some XTHs hydrolyse xyloglucan by xyloglucan hydrolase, XEH EC 3.2.1.151, action
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physiological function
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DcXTH3 is associated with petal growth and development during carnation flower opening
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physiological function
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DcXTH2 is associated with petal growth and development during carnation flower opening
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additional information
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catalytic nucleophile is Glu85, general acid/base residue is Glu89, Asp87 is the so-called helper residue, molecular dynamics simulations of a branched tetradecasaccharide substrate XXXGXXXG in the active site of xyloglucan endo-transglycosylase. When Asp87 is deprotonated, electrostatic repulsion forces the nucleophilic away from C1 of the sugar ring in subsite 21 and the proton-donating ability of Glu89 iss also weakened due to the formation of a hydrogen bond with Asp87, whereas protonation of Asp87 results in the formation of a hydrogen bond with the catalytic nucleophile and correct positioning of the catalytic machinery
additional information
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key structural features controlling the activity may involve the loop 1 and 2 regions of the XTH enzymes, homology modeling, detailed overview. The homology models of all 40 poplar XTH proteins is mainly focused on the areas near loop 1 and loop 2
additional information
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Plants that overexpress GhXTH1 have increased XTH activity and produce mature cotton fibers that are between 15 and 20% longer than wild-type cotton plants under both greenhouse and field growth conditions
additional information
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transgenic up-regulation of XET activity induced changes in cell wall xyloglucan, but its effects are dependent on developmental stage. For instance, XET overexpression increases abundance of the CCRC-M1 epitope in cambial cells and xylem cells in early stages of differentiation but not in mature xylem. Correspondingly, an increase in tightly bound xyloglucan content is observed in primary-walled xylem but a decrease is seen in secondary-walled xylem
additional information
PrXTH1 homology structure modeling using crystal structure of poplar xyloglucan endotransglycosylase Ptt-XET16A, PDB ID 1UMZ
additional information
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analysis of the xyloglucan endotransglucosylase/hydrolase gene family during apple fruit ripening and softening, overview
additional information
analysis of the xyloglucan endotransglucosylase/hydrolase gene family during apple fruit ripening and softening, overview
additional information
three-dimensional structure modelling of DkXTH1 based on the template of the crystal structure of PttXET16A (PDB ID 1un1)
additional information
three-dimensional structure modelling of DkXTH1 based on the template of the crystal structure of PttXET16A (PDB ID 1un1)
additional information
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three-dimensional structure modelling of DkXTH1 based on the template of the crystal structure of PttXET16A (PDB ID 1un1)
additional information
three-dimensional structure modelling of DkXTH2 based on the template of the crystal structure of PttXET16A (PDB ID 1un1)
additional information
three-dimensional structure modelling of DkXTH2 based on the template of the crystal structure of PttXET16A (PDB ID 1un1)
additional information
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three-dimensional structure modelling of DkXTH2 based on the template of the crystal structure of PttXET16A (PDB ID 1un1)
additional information
XTHs in dilute solution bind to diverse surfaces (e.g. glass and cellulose), and certain cold-water-extractable, heat-stable polymers (CHPs), e.g. from cauliflower florets, can re-solubilise the bound enzyme, re-activating it. Cell walls prepared from cauliflower florets, mung bean shoots and Arabidopsis cell-suspension cultures each contain endogenous, tightly bound, inactive XTHs, which are likewise rapidly solubilised and thus activated by cauliflower XTH-activating factor (XAF). Analysis of XTH-activating factor (XAF) activity of CHP preparations from diverse plant sources, CHPs from all plants tested possess XAF activity, overview
additional information
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XTHs in dilute solution bind to diverse surfaces (e.g. glass and cellulose), and certain cold-water-extractable, heat-stable polymers (CHPs), e.g. from cauliflower florets, can re-solubilise the bound enzyme, re-activating it. Cell walls prepared from cauliflower florets, mung bean shoots and Arabidopsis cell-suspension cultures each contain endogenous, tightly bound, inactive XTHs, which are likewise rapidly solubilised and thus activated by cauliflower XTH-activating factor (XAF). Analysis of XTH-activating factor (XAF) activity of CHP preparations from diverse plant sources, CHPs from all plants tested possess XAF activity, overview
additional information
XTHs in dilute solution bind to diverse surfaces (e.g. glass and cellulose), and certain cold-water-extractable, heat-stable polymers (CHPs), e.g. from cauliflower florets, can re-solubilise the bound enzyme, re-activating it. Cell walls prepared from cauliflower florets, mung bean shoots and Arabidopsis cell-suspension cultures each contain endogenous, tightly bound, inactive XTHs, which are likewise rapidly solubilised and thus activated by cauliflower XTH-activating factor (XAF). Analysis of XTH-activating factor (XAF) activity of CHP preparations from diverse plant sources, CHPs from all plants tested possess XAF activity, overview
additional information
XTHs in dilute solution bind to diverse surfaces (e.g. glass and cellulose), and certain cold-water-extractable, heat-stable polymers (CHPs), e.g. from cauliflower florets, can re-solubilise the bound enzyme, re-activating it. Cell walls prepared from cauliflower florets, mung bean shoots and Arabidopsis cell-suspension cultures each contain endogenous, tightly bound, inactive XTHs, which are likewise rapidly solubilised and thus activated by cauliflower XTH-activating factor (XAF). Analysis of XTH-activating factor (XAF) activity of CHP preparations from diverse plant sources, CHPs from all plants tested possess XAF activity, overview
additional information
docking studies, molecular dynamics simulation and modeling of a three-dimensional structure of FcXTH2 using the structure of TmNXG1 (PDB ID 2UWA) as template. Analysis of the molecular mechanism of interaction of FcXTH2 with xyloglucans as substrate
additional information
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docking studies, molecular dynamics simulation and modeling of a three-dimensional structure of FcXTH2 using the structure of TmNXG1 (PDB ID 2UWA) as template. Analysis of the molecular mechanism of interaction of FcXTH2 with xyloglucans as substrate
additional information
homology modeling of TmXET6.3 constructed based on the coordinates of the crystal structure of hybrid aspen PttXET16A as the template (PDB ID 1UN1). H94, A104, Q108, K234 and K237 are the key residues that underpinned the acceptor substrate specificity of TmXET6.3, evaluations of TmXET6.3 transglycosylation activities
additional information
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homology modeling of TmXET6.3 constructed based on the coordinates of the crystal structure of hybrid aspen PttXET16A as the template (PDB ID 1UN1). H94, A104, Q108, K234 and K237 are the key residues that underpinned the acceptor substrate specificity of TmXET6.3, evaluations of TmXET6.3 transglycosylation activities
additional information
structural modeling and analysis of PtoXTH proteins
additional information
structural modeling and analysis of PtoXTH proteins
additional information
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structural modeling and analysis of PtoXTH proteins
additional information
the model structure of the PrXTH1 is reported, displaying a beta-sandwich structure characteristic of the XTH protein family, with the catalytic residues in the middle of the protein structure, composed of residues Glu79, Asp81, and Glu83
additional information
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XTHs have a tendency to bind to various surfaces, including chromatography columns and cellulose. Bovine serum albumin (BSA) minimizes binding of solubilized XTHs to tube walls. BSA is the only agent which leads to the measured XET activity being proportional to the concentration of added enzyme: in all three types of plastic, reducing the concentration of the crude enzyme solution from 50% v/v to 15% v/v decrease the measured XET reaction rate by about 70%. Therefore, BSA at 2.5 mg/mL is included in the reaction mixture used in all subsequent XET assays
additional information
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Plants that overexpress GhXTH1 have increased XTH activity and produce mature cotton fibers that are between 15 and 20% longer than wild-type cotton plants under both greenhouse and field growth conditions
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