scholarly journals Analysis of the diversity of the glycoside hydrolase family 130 in mammal gut microbiomes reveals a novel mannoside-phosphorylase function

2020 ◽  
Vol 6 (10) ◽  
Author(s):  
Ao Li ◽  
Elisabeth Laville ◽  
Laurence Tarquis ◽  
Vincent Lombard ◽  
David Ropartz ◽  
...  

Mannoside phosphorylases are involved in the intracellular metabolization of mannooligosaccharides, and are also useful enzymes for the in vitro synthesis of oligosaccharides. They are found in glycoside hydrolase family GH130. Here we report on an analysis of 6308 GH130 sequences, including 4714 from the human, bovine, porcine and murine microbiomes. Using sequence similarity networks, we divided the diversity of sequences into 15 mostly isofunctional meta-nodes; of these, 9 contained no experimentally characterized member. By examining the multiple sequence alignments in each meta-node, we predicted the determinants of the phosphorolytic mechanism and linkage specificity. We thus hypothesized that eight uncharacterized meta-nodes would be phosphorylases. These sequences are characterized by the absence of signal peptides and of the catalytic base. Those sequences with the conserved E/K, E/R and Y/R pairs of residues involved in substrate binding would target β-1,2-, β-1,3- and β-1,4-linked mannosyl residues, respectively. These predictions were tested by characterizing members of three of the uncharacterized meta-nodes from gut bacteria. We discovered the first known β-1,4-mannosyl-glucuronic acid phosphorylase, which targets a motif of the Shigella lipopolysaccharide O-antigen. This work uncovers a reliable strategy for the discovery of novel mannoside-phosphorylases, reveals possible interactions between gut bacteria, and identifies a biotechnological tool for the synthesis of antigenic oligosaccharides.

2016 ◽  
Vol 82 (14) ◽  
pp. 4340-4349 ◽  
Author(s):  
Damao Wang ◽  
Do Hyoung Kim ◽  
Nari Seo ◽  
Eun Ju Yun ◽  
Hyun Joo An ◽  
...  

ABSTRACTIn this study, we characterized Gly5M, originating from a marine bacterium, as a novel β-1,3-1,6-endoglucanase in glycoside hydrolase family 5 (GH5) in the Carbohydrate-Active enZyme database. Thegly5Mgene encodes Gly5M, a newly characterized enzyme from GH5 subfamily 47 (GH5_47) inSaccharophagus degradans2-40T. Thegly5Mgene was cloned and overexpressed inEscherichia coli. Through analysis of the enzymatic reaction products by thin-layer chromatography, high-performance liquid chromatography, and matrix-assisted laser desorption ionization–tandem time of flight mass spectrometry, Gly5M was identified as a novel β-1,3-endoglucanase (EC 3.2.1.39) and bacterial β-1,6-glucanase (EC 3.2.1.75) in GH5. The β-1,3-endoglucanase and β-1,6-endoglucanase activities were detected by using laminarin (a β-1,3-glucan with β-1,6-glycosidic linkages derived from brown macroalgae) and pustulan (a β-1,6-glucan derived from fungal cell walls) as the substrates, respectively. This enzyme also showed transglycosylase activity toward β-1,3-oligosaccharides when laminarioligosaccharides were used as the substrates. Since laminarin is the major form of glucan storage in brown macroalgae, Gly5M could be used to produce glucose and laminarioligosaccharides, using brown macroalgae, for industrial purposes.IMPORTANCEIn this study, we have discovered a novel β-1,3-1,6-endoglucanase with a unique transglycosylase activity, namely, Gly5M, from a marine bacterium,Saccharophagus degradans2-40T. Gly5M was identified as the newly found β-1,3-endoglucanase and bacterial β-1,6-glucanase in GH5. Gly5M is capable of cleaving glycosidic linkages of both β-1,3-glucans and β-1,6-glucans. Gly5M also possesses a transglycosylase activity toward β-1,3-oligosacchrides. Due to the broad specificity of Gly5M, this enzyme can be used to produce glucose or high-value β-1,3- and/or β-1,6-oligosaccharides.


Author(s):  
Shu Horikoshi ◽  
Wataru Saburi ◽  
Jian Yu ◽  
Hideyuki Matsuura ◽  
James R Ketudat Cairns ◽  
...  

ABSTRACT Plants possess many glycoside hydrolase family 1 (GH1) β-glucosidases, which physiologically function in cell wall metabolism and activation of bioactive substances, but most remain uncharacterized. One GH1 isoenzyme AtBGlu42 in Arabidopsis thaliana has been identified to hydrolyze scopolin using the gene deficient plants, but no enzymatic properties were obtained. Its sequence similarity to another functionally characterized enzyme Os1BGlu4 in rice suggests that AtBGlu42 also acts on oligosaccharides. Here, we show that the recombinant AtBGlu42 possesses high kcat/Km not only on scopolin, but also on various β-glucosides, cellooligosaccharides, and laminarioligosaccharides. Of the cellooligosaccharides, cellotriose was the most preferred. The crystal structure, determined at 1.7 Å resolution, suggests that Arg342 gives unfavorable binding to cellooligosaccharides at subsite +3. The mutants R342Y and R342A showed the highest preference on cellotetraose or cellopentaose with increased affinities at subsite +3, indicating that the residues at this position have an important role for chain length specificity.


2016 ◽  
Vol 83 (6) ◽  
Author(s):  
Hong Yang ◽  
Pengjun Shi ◽  
Yun Liu ◽  
Wei Xia ◽  
Xiaoyu Wang ◽  
...  

ABSTRACT Glycoside hydrolase (GH) family 12 comprises enzymes with a wide range of activities critical for the degradation of lignocellulose. However, the important roles of the loop regions of GH12 enzymes in substrate specificity and catalytic efficiency remain poorly understood. This study examined how the loop 3 region affects the enzymatic properties of GH12 glucanases using NfEG12A from Neosartorya fischeri P1 and EG (PDB 1KS4 ) from Aspergillus niger. Acidophilic and thermophilic NfEG12A had the highest catalytic efficiency (k cat/Km , 3,001 and 263 ml/mg/s toward lichenin and carboxymethyl cellulose sodium [CMC-Na], respectively) known so far. Based on the multiple-sequence alignment and homology modeling, two specific sequences (FN and STTQA) were identified in the loop 3 region of GH12 endoglucanases from fungi. To determine their functions, these sequences were introduced into NfEG12A, or the counterpart sequence STTQA was removed from EG. These modifications had no effects on the optimal pH and temperature or substrate specificity but changed the catalytic efficiency (k cat/Km ) of these enzymes (in descending order, NfEG12A [100%], NfEG12A-FN [140%], and NfEG12A-STTQA [190%]; EG [100%] and EGΔSTTQA [41%]). Molecular docking and dynamic simulation analyses revealed that the longer loop 3 in GH12 may strengthen the hydrogen-bond interactions between the substrate and protein, thereby increasing the turnover rate (k cat). This study provides a new insight to understand the vital roles of loop 3 for GH12 endoglucanases in catalysis. IMPORTANCE Loop structures play critical roles in the substrate specificity and catalytic hydrolysis of GH12 enzymes. Three typical loops exist in these enzymes. Loops 1 and 2 are recognized as the catalytic loops and are closely related to the substrate specificity and catalytic efficiency. Loop 3 locates in the −1 or +1 subsite and varies a lot in amino acid composition, which may play a role in catalysis. In this study, two GH12 glucanases, NfEG12A and EG, which were mutated by introducing or deleting partial loop 3 sequences FN and/or STTQA, were selected to identify the function of loop 3. It revealed that the longer loop 3 of GH12 glucanases may strengthen the hydrogen network interactions between the substrate and protein, consequently increasing the turnover rate (k cat). This study proposes a strategy to increase the catalytic efficiency of GH12 glucanases by improving the hydrogen network between substrates and catalytic loops.


2013 ◽  
Vol 80 (3) ◽  
pp. 917-927 ◽  
Author(s):  
Mun Su Rhee ◽  
Lusha Wei ◽  
Neha Sawhney ◽  
John D. Rice ◽  
Franz J. St. John ◽  
...  

ABSTRACTXylans are the predominant polysaccharides in hemicelluloses and an important potential source of biofuels and chemicals. The ability ofBacillus subtilissubsp.subtilisstrain 168 to utilize xylans has been ascribed to secreted glycoside hydrolase family 11 (GH11) and GH30 endoxylanases, encoded by thexynAandxynCgenes, respectively. Both of these enzymes have been defined with respect to structure and function. In this study, the effects of deletion of thexynAandxynCgenes, individually and in combination, were evaluated for xylan utilization and formation of acidic xylooligosaccharides. Parent strain 168 depolymerizes methylglucuronoxylans (MeGXn), releasing the xylobiose and xylotriose utilized for growth and accumulating the aldouronate methylglucuronoxylotriose (MeGX3) with some methylglucuronoxylotetraose (MeGX4). The combined GH11 and GH30 activities process the products generated by their respective actions on MeGXnto release a maximal amount of neutral xylooligosaccharides for assimilation and growth, at the same time forming MeGX3in which the internal xylose is substituted with methylglucuronate (MeG). Deletion ofxynAresults in the accumulation of β-1,4-xylooligosaccharides with degrees of polymerization ranging from 4 to 18 and an average degree of substitution of 1 in 7.2, each with a single MeG linked α-1,2 to the xylose penultimate to the xylose at the reducing terminus. Deletion of thexynCgene results in the accumulation of aldouronates comprised of 4 or more xylose residues in which the MeG may be linked α-1,2 to the xylose penultimate to the nonreducing xylose. TheseB. subtilislines may be used for the production of acidic xylooligosaccharides with applications in human and veterinary medicine.


2013 ◽  
Vol 79 (19) ◽  
pp. 5788-5798 ◽  
Author(s):  
Chang-Hao Cui ◽  
Qing-Mei Liu ◽  
Jin-Kwang Kim ◽  
Bong-Hyun Sung ◽  
Song-Gun Kim ◽  
...  

ABSTRACTHere, we isolated and characterized a new ginsenoside-transforming β-glucosidase (BglQM) fromMucilaginibactersp. strain QM49 that shows biotransformation activity for various major ginsenosides. The gene responsible for this activity,bglQM, consists of 2,346 bp and is predicted to encode 781 amino acid residues. This enzyme has a molecular mass of 85.6 kDa. Sequence analysis of BglQM revealed that it could be classified into glycoside hydrolase family 3. The enzyme was overexpressed inEscherichia coliBL21(DE3) using a maltose binding protein (MBP)-fused pMAL-c2x vector system containing the tobacco etch virus (TEV) proteolytic cleavage site. Overexpressed recombinant BglQM could efficiently transform the protopanaxatriol-type ginsenosides Re and Rg1into (S)-Rg2and (S)-Rh1, respectively, by hydrolyzing one glucose moiety attached to the C-20 position at pH 8.0 and 30°C. TheKmvalues forp-nitrophenyl-β-d-glucopyranoside, Re, and Rg1were 37.0 ± 0.4 μM and 3.22 ± 0.15 and 1.48 ± 0.09 mM, respectively, and theVmaxvalues were 33.4 ± 0.6 μmol min−1mg−1of protein and 19.2 ± 0.2 and 28.8 ± 0.27 nmol min−1mg−1of protein, respectively. A crude protopanaxatriol-type ginsenoside mixture (PPTGM) was treated with BglQM, followed by silica column purification, to produce (S)-Rh1and (S)-Rg2at chromatographic purities of 98% ± 0.5% and 97% ± 1.2%, respectively. This is the first report of gram-scale production of (S)-Rh1and (S)-Rg2from PPTGM using a novel ginsenoside-transforming β-glucosidase of glycoside hydrolase family 3.


2016 ◽  
Author(s):  
Jiujun Cheng ◽  
Tatyana Romantsov ◽  
Katja Engel ◽  
Andrew C. Doxey ◽  
David R. Rose ◽  
...  

AbstractA soil metagenomic library carried in pJC8 (an IncP cosmid) was used for functional complementation for β-galactosidase activity in bothα-Proteobacteria (Sinorhizobium meliloti)andγ-Proteobacteria (Escherichia coli).Oneβ-galactosidase, encoded by overlapping clones selected in both hosts, was identified as a member of glycoside hydrolase family 2. ORFs obviously encoding possible β-galactosidases were not identified in 19 other clones that were only able to complementS. meliloti.Based on low sequence similarity to known glycoside hydrolases but not β-galactosidases, three ORFs were examined further. Biochemical analysis confirmed that all encodedβ-galactosidase activity. Bioinformatic and structural modeling implied that Lac161_ORF10 protein represented a novel enzyme family with a five-bladed propeller glycoside hydrolase domain.


2015 ◽  
Vol 81 (20) ◽  
pp. 7223-7232 ◽  
Author(s):  
Yuxiang Bai ◽  
Rachel Maria van der Kaaij ◽  
Hans Leemhuis ◽  
Tjaard Pijning ◽  
Sander Sebastiaan van Leeuwen ◽  
...  

ABSTRACT4,6-α-Glucanotransferase (4,6-α-GTase) enzymes, such as GTFB and GTFW ofLactobacillus reuteristrains, constitute a new reaction specificity in glycoside hydrolase family 70 (GH70) and are novel enzymes that convert starch or starch hydrolysates into isomalto/maltopolysaccharides (IMMPs). These IMMPs still have linear chains with some α1→4 linkages but mostly (relatively long) linear chains with α1→6 linkages and are soluble dietary starch fibers. 4,6-α-GTase enzymes and their products have significant potential for industrial applications. Here we report that an N-terminal truncation (amino acids 1 to 733) strongly enhances the soluble expression level of fully active GTFB-ΔN (approximately 75-fold compared to full-length wild type GTFB) inEscherichia coli. In addition, quantitative assays based on amylose V as the substrate are described; these assays allow accurate determination of both hydrolysis (minor) activity (glucose release, reducing power) and total activity (iodine staining) and calculation of the transferase (major) activity of these 4,6-α-GTase enzymes. The data show that GTFB-ΔN is clearly less hydrolytic than GTFW, which is also supported by nuclear magnetic resonance (NMR) analysis of their final products. From these assays, the biochemical properties of GTFB-ΔN were characterized in detail, including determination of kinetic parameters and acceptor substrate specificity. The GTFB enzyme displayed high conversion yields at relatively high substrate concentrations, a promising feature for industrial application.


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