Structural insights into the catalytic mechanism of a novel glycoside hydrolase family 113 β-1,4-mannanase from Amphibacillus xylanus.

ABSTRACT: β-1,4-Mannanase degrades β-1,4-mannan polymers into manno-oligosaccharides with a low degree of polymerization. To date, only one glycoside hydrolase (GH) family 113 β-1,4-mannanase, from Alicyclobacillus acidocaldarius (AaManA), has been structurally characterized, and no complex structure of enzyme-manno-oligosaccharides from this family has been reported. Here, crystal structures of a GH family 113 β-1,4-mannanase from Amphibacillus xylanus (AxMan113A) and its complexes with mannobiose, mannotriose, mannopentaose, and mannahexaose were solved. AxMan113A had higher affinity for -1 and +1 mannoses, which explains why the enzyme can hydrolyze mannobiose. At least six subsites (-4 to +2) exist in the groove, but mannose units preferentially occupied subsit

SUBMITTER: You X 

PROVIDER: S-EPMC6066303 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature