scholarly journals CalkGH9T: A Glycoside Hydrolase Family 9 Enzyme from Clostridium alkalicellulosi

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1011
Author(s):  
Paripok Phitsuwan ◽  
Sengthong Lee ◽  
Techly San ◽  
Khanok Ratanakhanokchai
Keyword(s):  
Glycoside Hydrolase ◽  
Cellulose Degradation ◽  
Glycoside Hydrolase Family ◽  
Carbohydrate Binding ◽  
Type I ◽  
Amorphous Cellulose ◽  
Carbohydrate Binding Modules ◽  
Glycoside Hydrolase Family 9 ◽  
Hydrolysis Of ◽  
Hydrolase Family

Glycoside hydrolase family 9 (GH9) endoglucanases are important enzymes for cellulose degradation. However, their activity on cellulose is diverse. Here, we cloned and expressed one GH9 enzyme (CalkGH9T) from Clostridium alkalicellulosi in Escherichia coli. CalkGH9T has a modular structure, containing one GH9 catalytic module, two family 3 carbohydrate binding modules, and one type I dockerin domain. CalkGH9T exhibited maximal activity at pH 7.0–8.0 and 55 °C and was resistant to urea and NaCl. It efficiently hydrolyzed carboxymethyl cellulose (CMC) but poorly degraded regenerated amorphous cellulose (RAC). Despite strongly binding to Avicel, CalkGH9T lacked the ability to hydrolyze this substrate. The hydrolysis of CMC by CalkGH9T produced a series of cello-oligomers, with cellotetraose being preferentially released. Similar proportions of soluble and insoluble reducing ends generated by hydrolysis of RAC indicated non-processive activity. Our study extends our knowledge of the molecular mechanism of cellulose hydrolysis by GH9 family endoglucanases with industrial relevance.

scholarly journals Molecular cloning and characterization of a novel β-1,3-xylanase possessing two putative carbohydrate-binding modules from a marine bacterium Vibrio sp. strain AX-4

2005 ◽  
Vol 388 (3) ◽  
pp. 949-957 ◽  
Author(s):  
Masashi KIYOHARA ◽  
Keishi SAKAGUCHI ◽  
Kuniko YAMAGUCHI ◽  
Toshiyoshi ARAKI ◽  
Takashi NAKAMURA ◽  
...  
Keyword(s):  
Glycoside Hydrolase ◽  
Marine Bacterium ◽  
Glycoside Hydrolase Family ◽  
Carbohydrate Binding ◽  
Amino Acid Residues ◽  
Reading Frame ◽  
Carbohydrate Binding Modules ◽  
Hydrolysis Of ◽  
Hydrolase Family

We cloned a novel β-1,3-xylanase gene, consisting of a 1728-bp open reading frame encoding 576 amino acid residues, from a marine bacterium, Vibrio sp. strain AX-4. Sequence analysis revealed that the β-1,3-xylanase is a modular enzyme composed of a putative catalytic module belonging to glycoside hydrolase family 26 and two putative carbohydrate-binding modules belonging to family 31. The recombinant enzyme hydrolysed β-1,3-xylan to yield xylo-oligosaccharides with different numbers of xylose units, mainly xylobiose, xylotriose and xylotetraose. However, the enzyme did not hydrolyse β-1,4-xylan, β-1,4-mannan, β-1,4-glucan, β-1,3-xylobiose or p-nitrophenyl-β-xyloside. When β-1,3-xylo-oligosaccharides were used as the substrate, the kcat value of the enzyme for xylopentaose was found to be 40 times higher than that for xylotetraose, and xylotriose was extremely resistant to hydrolysis by the enzyme. A PSI-BLAST search revealed two possible catalytic Glu residues (Glu-138 as an acid/base catalyst and Glu-234 as a nucleophile), both of which are generally conserved in glycoside hydrolase superfamily A. Replacement of these two conserved Glu residues with Asp and Gln resulted in a significant decrease and complete loss of enzyme activity respectively, without a change in their CD spectra, suggesting that these Glu residues are the catalytic residues of β-1,3-xylanase. The present study also clearly shows that the non-catalytic putative carbohydrate-binding modules play an important role in the hydrolysis of insoluble β-1,3-xylan, but not that of soluble glycol-β-1,3-xylan. Furthermore, repeating a putative carbohydrate-binding module strongly enhanced the hydrolysis of the insoluble substrate.

scholarly journals Crystallographic analysis shows substrate binding at the −3 to +1 active-site subsites and at the surface of glycoside hydrolase family 11 endo-1,4-β-xylanases

2008 ◽  
Vol 410 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Elien Vandermarliere ◽  
Tine M. Bourgois ◽  
Sigrid Rombouts ◽  
Steven van Campenhout ◽  
Guido Volckaert ◽  
...  
Keyword(s):  
Binding Site ◽  
Active Site ◽  
Glycoside Hydrolase ◽  
Plant Cell Wall ◽  
Substrate Binding ◽  
Crystallographic Analysis ◽  
Glycoside Hydrolase Family ◽  
Carbohydrate Binding ◽  
Carbohydrate Binding Modules ◽  
Hydrolase Family

GH 11 (glycoside hydrolase family 11) xylanases are predominant enzymes in the hydrolysis of heteroxylan, an abundant structural polysaccharide in the plant cell wall. To gain more insight into the protein–ligand interactions of the glycone as well as the aglycone subsites of these enzymes, catalytically incompetent mutants of the Bacillus subtilis and Aspergillus niger xylanases were crystallized, soaked with xylo-oligosaccharides and subjected to X-ray analysis. For both xylanases, there was clear density for xylose residues in the −1 and −2 subsites. In addition, for the B. subtilis xylanase, there was also density for xylose residues in the −3 and +1 subsite showing the spanning of the −1/+1 subsites. These results, together with the observation that some residues in the aglycone subsites clearly adopt a different conformation upon substrate binding, allowed us to identify the residues important for substrate binding in the aglycone subsites. In addition to substrate binding in the active site of the enzymes, the existence of an unproductive second ligand-binding site located on the surface of both the B. subtilis and A. niger xylanases was observed. This extra binding site may have a function similar to the separate carbohydrate-binding modules of other glycoside hydrolase families.

Characterization of a Theme C Glycoside Hydrolase Family 9 Endo-Beta-Glucanase from a Biogas Reactor Metagenome

2018 ◽  
Vol 37 (5) ◽  
pp. 454-460
Author(s):  
Carola Schröder ◽  
Christin Burkhardt ◽  
Philip Busch ◽  
Georg Schirrmacher ◽  
Jörg Claren ◽  
...  
Keyword(s):  
Glycoside Hydrolase ◽  
Glycoside Hydrolase Family ◽  
Beta Glucanase ◽  
Glycoside Hydrolase Family 9 ◽  
Biogas Reactor ◽  
Hydrolase Family

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.

scholarly journals Comparative Analyses of Two Thermophilic Enzymes Exhibiting both β-1,4 Mannosidic and β-1,4 Glucosidic Cleavage Activities from Caldanaerobius polysaccharolyticus

2010 ◽  
Vol 192 (16) ◽  
pp. 4111-4121 ◽  
Author(s):  
Yejun Han ◽  
Dylan Dodd ◽  
Charles W. Hespen ◽  
Samuel Ohene-Adjei ◽  
Charles M. Schroeder ◽  
...  
Keyword(s):  
Catalytic Domain ◽  
Biochemical Properties ◽  
Degree Of Polymerization ◽  
Glycoside Hydrolase Family ◽  
Carbohydrate Binding ◽  
Biofuel Industry ◽  
Carbohydrate Binding Modules ◽  
Mannanase Activity ◽  
Hydrolysis Of ◽  
Derivatives Of

ABSTRACT The hydrolysis of polysaccharides containing mannan requires endo-1,4-β-mannanase and 1,4-β-mannosidase activities. In the current report, the biochemical properties of two endo-β-1,4-mannanases (Man5A and Man5B) from Caldanaerobius polysaccharolyticus were studied. Man5A is composed of an N-terminal signal peptide (SP), a catalytic domain, two carbohydrate-binding modules (CBMs), and three surface layer homology (SLH) repeats, whereas Man5B lacks the SP, CBMs, and SLH repeats. To gain insights into how the two glycoside hydrolase family 5 (GH5) enzymes may aid the bacterium in energy acquisition and also the potential application of the two enzymes in the biofuel industry, two derivatives of Man5A (Man5A-TM1 [TM1 stands for truncational mutant 1], which lacks the SP and SLH repeats, and Man5A-TM2, which lacks the SP, CBMs, and SLH repeats) and the wild-type Man5B were biochemically analyzed. The Man5A derivatives displayed endo-1,4-β-mannanase and endo-1,4-β-glucanase activities and hydrolyzed oligosaccharides with a degree of polymerization (DP) of 4 or higher. Man5B exhibited endo-1,4-β-mannanase activity and little endo-1,4-β-glucanase activity; however, this enzyme also exhibited 1,4-β-mannosidase and cellodextrinase activities. Man5A-TM1, compared to either Man5A-TM2 or Man5B, had higher catalytic activity with soluble and insoluble polysaccharides, indicating that the CBMs enhance catalysis of Man5A. Furthermore, Man5A-TM1 acted synergistically with Man5B in the hydrolysis of β-mannan and carboxymethyl cellulose. The versatility of the two enzymes, therefore, makes them a resource for depolymerization of mannan-containing polysaccharides in the biofuel industry. Furthermore, on the basis of the biochemical and genomic data, a molecular mechanism for utilization of mannan-containing nutrients by C. polysaccharolyticus is proposed.

scholarly journals The structure of PfGH50B, an agarase from the marine bacterium Pseudoalteromonas fuliginea PS47

2020 ◽  
Vol 76 (9) ◽  
pp. 422-427
Author(s):  
Benjamin Pluvinage ◽  
Craig S. Robb ◽  
Roderick Jeffries ◽  
Alisdair B. Boraston
Keyword(s):  
Glycoside Hydrolase ◽  
Marine Bacterium ◽  
Structural Features ◽  
Degree Of Polymerization ◽  
Glycoside Hydrolase Family ◽  
Carbohydrate Binding ◽  
X Ray ◽  
Terminal Domain ◽  
Polysaccharide Utilization Locus ◽  
Hydrolase Family

The recently identified marine bacterium Pseudoalteromonas fuliginea sp. PS47 possesses a polysaccharide-utilization locus dedicated to agarose degradation. In particular, it contains a gene (locus tag EU509_06755) encoding a β-agarase that belongs to glycoside hydrolase family 50 (GH50), PfGH50B. The 2.0 Å resolution X-ray crystal structure of PfGH50B reveals a rare complex multidomain fold that was found in two of the three previously determined GH50 structures. The structure comprises an N-terminal domain with a carbohydrate-binding module (CBM)-like fold fused to a C-terminal domain by a rigid linker. The CBM-like domain appears to function by extending the catalytic groove of the enzyme. Furthermore, the PfGH50B structure highlights key structural features in the mobile loops that may function to restrict the degree of polymerization of the neoagaro-oligosaccharide products and the enzyme processivity.

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