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Molecular basis of substrate specificity in family 1 glycoside hydrolases
Author(s) -
Marana Sandro R.
Publication year - 2006
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216540600617156
Subject(s) - aglycone , chemistry , stereochemistry , glycoside hydrolase , active site , substrate (aquarium) , hydrogen bond , hydrolase , glycosidic bond , enzyme , glycoside , biochemistry , organic chemistry , molecule , oceanography , geology
β‐glycosidases are active upon a large range of substrates. Besides this, subtle changes in the substrate structure may result in large modifications on the β‐glycosidase activity. The characterization of the molecular basis of β‐glycosidases substrate preference may contribute to the comprehension of the enzymatic specificity, a fundamental property of biological systems. β‐glycosidases specificity for the monosaccharide of the substrate nonreducing end (glycone) is controlled by a hydrogen bond network involving at least 5 active site amino acid residues and 4 substrate hydroxyls. From these residues, a glutamate, which interacts with hydroxyls 4 and 6, seems to be a key element in the determination of the preference for fucosides, glucosides and galactosides. Apart from this, interactions with the hydroxyl 2 are essential to the β‐glycosidase activity. The active site residues forming these interactions and the pattern of the hydrogen bond network are conserved among all β‐glycosidases. The region of the β‐glycosidase active site that interacts with the moiety (called aglycone) which is bound to the glycone is formed by several subsites (1 to 3). However, the majority of the non‐covalent interactions with the aglycone is concentrated in the first one, which presents a variable spatial structure and amino acid composition. This structural variability is in accordance with the high diversity of aglycones recognized by β‐glycosidases. Hydrophobic interactions and hydrogen bonds are formed with the aglycone, but the manner in which they control the β‐glycosidase specificity still remains to be determined.iubmb Life, 58: 63‐73, 2006