scholarly journals A novel member of glycoside hydrolase family 30 subfamily 8 with altered substrate specificity

2014 ◽  
Vol 70 (11) ◽  
pp. 2950-2958 ◽  
Author(s):  
Franz J. St John ◽  
Diane Dietrich ◽  
Casey Crooks ◽  
Edwin Pozharski ◽  
Javier M. González ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Glycoside Hydrolase ◽  
Biochemical Characterization ◽  
Amino Acid Identity ◽  
Glycoside Hydrolase Family ◽  
High Sequence Identity ◽  
Loop Region ◽  
Hydrolysis Of ◽  
Hydrolase Family ◽  
Glycoside Hydrolase Family 30

Endoxylanases classified into glycoside hydrolase family 30 subfamily 8 (GH30-8) are known to hydrolyze the hemicellulosic polysaccharide glucuronoxylan (GX) but not arabinoxylan or neutral xylooligosaccharides. This is owing to the specificity of these enzymes for the α-1,2-linked glucuronate (GA) appendage of GX. Limit hydrolysis of this substrate produces a series of aldouronates each containing a single GA substituted on the xylose penultimate to the reducing terminus. In this work, the structural and biochemical characterization of xylanase 30A fromClostridium papyrosolvens(CpXyn30A) is presented. This xylanase possesses a high degree of amino-acid identity to the canonical GH30-8 enzymes, but lacks the hallmark β8–α8 loop region which in part defines the function of this GH30 subfamily and its role in GA recognition.CpXyn30A is shown to have a similarly low activity on all xylan substrates, while hydrolysis of xylohexaose revealed a competing transglycosylation reaction. These findings are directly compared with the model GH30-8 enzyme fromBacillus subtilis, XynC. Despite its high sequence identity to the GH30-8 enzymes,CpXyn30A does not have any apparent specificity for the GA appendage. These findings confirm that the typically conserved β8–α8 loop region of these enzymes influences xylan substrate specificity but not necessarily β-1,4-xylanase function.

scholarly journals Mode of Action of GH30-7 Reducing-End Xylose-Releasing Exoxylanase A (Xyn30A) from the Filamentous Fungus Talaromyces cellulolyticus

2019 ◽  
Vol 85 (13) ◽  
Author(s):  
Yusuke Nakamichi ◽  
Thierry Fouquet ◽  
Shotaro Ito ◽  
Akinori Matsushika ◽  
Hiroyuki Inoue
Keyword(s):  
Mode Of Action ◽  
Glycoside Hydrolase ◽  
Glycoside Hydrolase Family ◽  
Fungal Enzymes ◽  
Content Type ◽  
Talaromyces Cellulolyticus ◽  
Bacteria And Fungi ◽  
Hydrolysis Of ◽  
Hydrolase Family ◽  
Glycoside Hydrolase Family 30

ABSTRACT In this study, we characterized the mode of action of reducing-end xylose-releasing exoxylanase (Rex), which belongs to the glycoside hydrolase family 30-7 (GH30-7). GH30-7 Rex, isolated from the cellulolytic fungus Talaromyces cellulolyticus (Xyn30A), exists as a dimer. The purified Xyn30A released xylose from linear xylooligosaccharides (XOSs) 3 to 6 xylose units in length with similar kinetic constants. Hydrolysis of branched, borohydride-reduced, and p-nitrophenyl XOSs clarified that Xyn30A possesses a Rex activity. 1H nuclear magnetic resonance (1H NMR) analysis of xylotriose hydrolysate indicated that Xyn30A degraded XOSs via a retaining mechanism and without recognizing an anomeric structure at the reducing end. Hydrolysis of xylan by Xyn30A revealed that the enzyme continuously liberated both xylose and two types of acidic XOSs: 22-(4-O-methyl-α-d-glucuronyl)-xylotriose (MeGlcA2Xyl3) and 22-(MeGlcA)-xylobiose (MeGlcA2Xyl2). These acidic products were also detected during hydrolysis using a mixture of MeGlcA2Xyln (n = 2 to 14) as the substrate. This indicates that Xyn30A can release MeGlcA2Xyln (n = 2 and 3) in an exo manner. Comparison of subsites in Xyn30A and GH30-7 glucuronoxylanase using homology modeling suggested that the binding of the reducing-end residue at subsite +2 was partially prevented by a Gln residue conserved in GH30-7 Rex; additionally, the Arg residue at subsite −2b, which is conserved in glucuronoxylanase, was not found in Xyn30A. Our results lead us to propose that GH30-7 Rex plays a complementary role in hydrolysis of xylan by fungal cellulolytic systems. IMPORTANCE Endo- and exo-type xylanases depolymerize xylan and play crucial roles in the assimilation of xylan in bacteria and fungi. Exoxylanases release xylose from the reducing or nonreducing ends of xylooligosaccharides; this is generated by the activity of endoxylanases. β-Xylosidase, which hydrolyzes xylose residues on the nonreducing end of a substrate, is well studied. However, the function of reducing-end xylose-releasing exoxylanases (Rex), especially in fungal cellulolytic systems, remains unclear. This study revealed the mode of xylan hydrolysis by Rex from the cellulolytic fungus Talaromyces cellulolyticus (Xyn30A), which belongs to the glycoside hydrolase family 30-7 (GH30-7). A conserved residue related to Rex activity is found in the substrate-binding site of Xyn30A. These findings will enhance our understanding of the function of GH30-7 Rex in the cooperative hydrolysis of xylan by fungal enzymes.

Structural and biochemical characterization of novel bacterial α-galactosidases belonging to glycoside hydrolase family 31

2015 ◽  
Vol 469 (1) ◽  
pp. 145-158 ◽  
Author(s):  
Takatsugu Miyazaki ◽  
Yuichi Ishizaki ◽  
Megumi Ichikawa ◽  
Atsushi Nishikawa ◽  
Takashi Tonozuka
Keyword(s):  
Substrate Specificity ◽  
Crystal Structures ◽  
Glycoside Hydrolase ◽  
Biochemical Characterization ◽  
Glycoside Hydrolase Family ◽  
Galactosidase Activity ◽  
Gh31 Family ◽  
Glycoside Hydrolase Family 31 ◽  
Hydrolase Family

We identified two bacterial enzymes as the first members that displayed α-galactosidase activity and the crystal structures provided insights into their novel substrate specificity. This is the first report of α-galactosidases which belong to the GH31 family.

Xylanases of glycoside hydrolase family 30 – An overview

2021 ◽  
Vol 47 ◽  
pp. 107704
Author(s):  
Vladimír Puchart ◽  
Katarína Šuchová ◽  
Peter Biely
Keyword(s):  
Glycoside Hydrolase ◽  
Glycoside Hydrolase Family ◽  
Hydrolase Family ◽  
Glycoside Hydrolase Family 30

scholarly journals Structure of a bacterial glycoside hydrolase family 63 enzyme in complex with its glycosynthase product, and insights into the substrate specificity

FEBS Journal ◽  
2013 ◽  
Vol 280 (18) ◽  
pp. 4560-4571 ◽  
Author(s):  
Takatsugu Miyazaki ◽  
Megumi Ichikawa ◽  
Gaku Yokoi ◽  
Motomitsu Kitaoka ◽  
Haruhide Mori ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Glycoside Hydrolase ◽  
Glycoside Hydrolase Family ◽  
Hydrolase Family

scholarly journals Substrate Specificity in Glycoside Hydrolase Family 10

2000 ◽  
Vol 275 (30) ◽  
pp. 23020-23026 ◽  
Author(s):  
Valérie Ducros ◽  
Simon J. Charnock ◽  
Urszula Derewenda ◽  
Zygmunt S. Derewenda ◽  
Zbigniew Dauter ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Glycoside Hydrolase ◽  
Glycoside Hydrolase Family ◽  
Glycoside Hydrolase Family 10 ◽  
Hydrolase Family

scholarly journals Biochemical characterization of a glycoside hydrolase family 43 β-D-galactofuranosidase from the fungus Aspergillus niger

2021 ◽  
Author(s):  
Gregory S Bulmer ◽  
Fang Wei Yuen ◽  
Naimah Begum ◽  
Bethan S Jones ◽  
Sabine S Flitsch ◽  
...  
Keyword(s):  
Aspergillus Niger ◽  
Glycoside Hydrolase ◽  
Biochemical Characterization ◽  
Maximum Activity ◽  
Glycoside Hydrolase Family ◽  
Enzyme Specificity ◽  
Fungal Enzymes ◽  
Glycoside Hydrolase Family 43 ◽  
Hydrolase Family

β-D-Galactofuranose (Galf) and its polysaccharides are found in bacteria, fungi and protozoa but do not occur in mammalian tissues, and thus represent a specific target for anti-pathogenic drugs. Understanding the enzymatic degradation of these polysaccharides is therefore of great interest, but the identity of fungal enzymes with exclusively galactofuranosidase activity has so far remained elusive. Here we describe the identification and characterization of a galactofuranosidase from the industrially important fungus Aspergillus niger. Phylogenetic analysis of glycoside hydrolase family 43 subfamily 34 (GH43_34) members revealed the occurrence of three distinct clusters and, by comparison with specificities of characterized bacterial members, suggested a basis for prediction of enzyme specificity. Using this rationale, in tandem with molecular docking, we identified a putative β-D-galactofuranosidase from A. niger which was recombinantly expressed in Escherichia coli. The Galf-specific hydrolase, encoded by xynD demonstrates maximum activity at pH 5, 25 °C towards 4-Nitrophenyl-β-galactofuranoside (pNP-βGalf), with a Km of 17.9 ± 1.9 mM and Vmax of 70.6 ± 5.3 μmol min-1. The characterization of this first fungal GH43 galactofuranosidase offers further molecular insight into the degradation of Galf-containing structures and may inform clinical treatments against fungal pathogens.

β-Glucuronidase from Lactobacillus brevis useful for baicalin hydrolysis belongs to glycoside hydrolase family 30

2013 ◽  
Vol 98 (9) ◽  
pp. 4021-4032 ◽  
Author(s):  
Haruko Sakurama ◽  
Shigenobu Kishino ◽  
Yoshie Uchibori ◽  
Yasunori Yonejima ◽  
Hisashi Ashida ◽  
...  
Keyword(s):  
Glycoside Hydrolase ◽  
Lactobacillus Brevis ◽  
Glycoside Hydrolase Family ◽  
Hydrolase Family ◽  
Glycoside Hydrolase Family 30

scholarly journals Conversion of levoglucosan into glucose by the coordination of four enzymes through oxidation, elimination, hydration, and reduction

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yuya Kuritani ◽  
Kohei Sato ◽  
Hideo Dohra ◽  
Seiichiro Umemura ◽  
Motomitsu Kitaoka ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Recombinant Proteins ◽  
Metabolic Pathway ◽  
Glycoside Hydrolase ◽  
Gene Locus ◽  
Glycoside Hydrolase Family ◽  
Sequential Reaction ◽  
Layer Chromatography ◽  
Hydrolysis Of ◽  
Hydrolase Family

AbstractLevoglucosan (LG) is an anhydrosugar produced through glucan pyrolysis and is widely found in nature. We previously isolated an LG-utilizing thermophile, Bacillus smithii S-2701M, and suggested that this bacterium may have a metabolic pathway from LG to glucose, initiated by LG dehydrogenase (LGDH). Here, we completely elucidated the metabolic pathway of LG involving three novel enzymes in addition to LGDH. In the S-2701M genome, three genes expected to be involved in the LG metabolism were found in the vicinity of the LGDH gene locus. These four genes including LGDH gene (lgdA, lgdB1, lgdB2, and lgdC) were expressed in Escherichia coli and purified to obtain functional recombinant proteins. Thin layer chromatography analyses of the reactions with the combination of the four enzymes elucidated the following metabolic pathway: LgdA (LGDH) catalyzes 3-dehydrogenation of LG to produce 3-keto-LG, which undergoes β-elimination of 3-keto-LG by LgdB1, followed by hydration to produce 3-keto-d-glucose by LgdB2; next, LgdC reduces 3-keto-d-glucose to glucose. This sequential reaction mechanism resembles that proposed for an enzyme belonging to glycoside hydrolase family 4, and results in the observational hydrolysis of LG into glucose with coordination of the four enzymes.

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