Premium
Catalytic properties of a mutant β‐galactosidase from Xanthomonas manihotis engineered to synthesize galactosyl‐thio‐β‐1,3 and ‐β‐1,4‐glycosides
Author(s) -
Kim Young-Wan,
Chen Hongming,
Kim Jin Hyo,
Withers Stephen G.
Publication year - 2006
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2006.06.095
Subject(s) - mutant , chemistry , galactosyltransferase , thio , catalysis , glycosyl , stereochemistry , glycosyl donor , glycoside , glycosidic bond , biochemistry , enzyme , gene
The identity of the acid/base catalyst of the Family 35 β‐galactosidases from Xanthomonas manihotis (BgaX) has been confirmed as Glu184 by kinetic analysis of mutants modified at that position. The Glu184Ala mutant of BgaX is shown to function as an efficient thioglycoligase, which synthesises thiogalactosides with linkages to the 3 and 4 positions of glucosides and galactosides in high (>80%) yields. Kinetic analysis of the thioglycoligase reveals glycosyl donor K m values of 1.5–21 μM and glycosyl acceptor K m values from 180 to 500 μM. This mutant should be a valuable catalyst for the synthesis of metabolically stable analogues of this important glycosidic linkage.