Open AccessFamily 6 carbohydrate‐binding modules display multiple β1,3‐linked glucan‐specific binding interfaces
Author(s) -
Correia Márcia A.S.,
Pires Virgínia M.R.,
Gilbert Harry J.,
Bolam David N.,
Fernandes Vânia O.,
Alves Victor D.,
Prates José A.M.,
Ferreira Luís M.A.,
Fontes Carlos M.G.A.
Publication year - 2009
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2009.01764.x
Subject(s) - carbohydrate binding module , binding site , biochemistry , enzyme , chemistry , glucan , carbohydrate , glycoside hydrolase , stereochemistry
Noncatalytic carbohydrate‐binding modules (CBMs), which are found in a variety of carbohydrate‐degrading enzymes, have been grouped into sequence‐based families. CBMs, by recruiting their appended enzymes onto the surface of the target substrate, potentiate catalysis particularly against insoluble substrates. Family 6 CBMs (CBM6s) display unusual properties in that they present two potential ligand‐binding sites termed clefts A and B, respectively. Cleft B is located on the concave surface of the β‐sandwich fold while cleft A, the more common binding site, is formed by the loops that connect the inner and the outer β‐sheets. Here, we report the biochemical properties of CBM6‐1 from Cellvibrio mixtus Cm Cel5A. The data reveal that CBM6‐1 specifically recognizes β1,3‐glucans through residues located both in cleft A and in cleft B. In contrast, a previous report showed that a CBM6 derived from a Bacillus halodurans laminarinase binds to β1,3‐glucans only in cleft A. These studies reveal a different mechanism by which a highly conserved protein platform can recognize β1,3‐glucans.