Substrate specificity of Aspergillus oryzae family 3 beta-glucosidase.
Among glycoside hydrolases, beta-glucosidase plays a unique role in many physiological and biocatalytical processes that involve the beta-linked O-glycosyl bond of various oligomeric saccharides or glycosides. Structurally, the enzyme can be grouped into glycoside hydrolase family 1 and 3. Although the basic ("retaining, double-displacement") mechanism for the catalysis of family 3 beta-glucosidase has been established, in-depth understanding of its structure-function relationship, particularly the substrate specificity that is of great interest for developing the enzyme as a versatile biocatalyst, remains limited. To further probe the active site, we carried out a comparative study on a family 3 beta-glucosidase from Aspergillus oryzae with substrates and competitive inhibitors of different structures, in attempt to evaluate the site-specific spatial and chemical interactions between a pyranosyl substrate and the enzyme. Our results showed the enzyme having a strict stereochemical requirement (to accommodate beta-d-glucopyranose) for its "-1" active subsite, in contrast to its family 1 counterpart.
Langston
James
J
Novozymes, Inc., 1445 Drew Avenue, Davis, CA 95616, USA.
Sheehy
Neil
N
Xu
Feng
F
D000595:Amino Acid Sequence; D001236:Aspergillus oryzae / Q000201:enzymology*; D007700:Kinetics; D008969:Molecular Sequence Data; D009005:Monosaccharides / Q000737:chemistry; D005810:Multigene Family; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity; D001617:beta-Glucosidase / Q000037:antagonists & inhibitors / Q000145:classification* / Q000378:metabolism*
D009005:Monosaccharides; D011994:Recombinant Proteins; D001617:beta-Glucosidase