Two Novel Glycoside Hydrolases Responsible for the Catabolism of Cyclobis-(1→6)-α-nigerosyl

Abstract

18 s ؊1 mM ؊1 ) was 6.9-and 19-fold higher than those for panose and isomaltotriose, respectively. These results indicate that Kfla1896 is a new GH15 enzyme with high substrate specificity for isomaltose, suggesting the enzyme should be designated an isomaltose glucohydrolase. This is the first report to identify a starch-utilization pathway that proceeds via CNN.

Structural basis of the strict specificity of a bacterial GH31 α-1,3-glucosidase for nigerooligosaccharides

“…Other than glycoside hydrolases, a nigerose phosphorylase from Lachnoclostridium phytofermentans (formerly Clostridium phytofermentans) (Cphy1874) belonging to the GH65 family displays high specificity against nigerose (Table S1), but it does not catalyze hydrolysis (36). At present, the catalytic α subunit of ER α-glucosidase II, CADE (3,4), and Lactobacillus johnsonii α-1,3-glucosidase (LJAG31) (8) have been identified as GH31 enzymes that display specificity against α-1,3-glucosidic linkage. ER α-glucosidase II hydrolyzes α-1,3 linkages in the α-Glc-(1→3)-Glc and α-Glc-(1→3)-mannose moieties of Nglycans.…”

“…The biosynthesis and degradation of carbohydrates are catalyzed by carbohydrate-active enzymes (CAZymes), including glycoside hydrolases (GHs), glycosyltransferases, and polysaccharide lyases, and are classified into many families based on sequence similarity in the CAZy database (http://www.cazy.org) (1,2). GHs are involved in carbohydrate degradation and glycoside formation through transglycosylation reactions (3,4).…”

Crystal structure of the Enterococcus faecalis α‐N‐acetylgalactosaminidase, a member of the glycoside hydrolase family 31

“…GH31 enzymes have been identified as acting on α-glycosidic bonds, including α-glucosidase [8][9][10][11][12][13], α-1,3-glucosidase [14], mannosyl-oligosaccharide α-1,3-glucosidase [15,16], α-xylosidase [17][18][19], sucrase-isomaltase [20], α-galactosidase [2,21], sulfoquinovosidase [22,23], dextranase [24,25], and α-glucan lyase [26]. GH31 enzymes employ a retaining mechanism, and several enzymes catalyze transglycosylation to produce α-glucosidic linkages such as α-1,2, α-1,3, α-1,4, and α-1,6 [27][28][29][30]; cycloalternan-forming enzyme and cycloalternan degrading enzyme are also GH31 members [31,32]. All GH31 members share a (β/α) 8 -barrel catalytic domain and some β-sandwich domains at the N-and C-termini.…”

Structural insights reveal the second base catalyst of isomaltose glucohydrolase

“…GH15 was one of the first established GH groups, and five fungal glucoamylases (GAMase; EC 3.2.1.3) were classified into GH15 at the time of establishment [12]. Thereafter, glucodextranase (GDXase; EC 3.2.1.70) [13], α,α-trehalase (EC 3.2.1.28) [14,15], and dextran dextrinase (EC 2.4.1.2) and its related enzyme [16,17] were categorized into this family, and isomaltose glucohydrolase (IGHase; EC 3.2.1.205) [18] was found most recently.…”