4bce

Publication Abstract from PubMed

A large number of retaining glycosidases catalyze both hydrolysis and transglycosylation reactions, but little is known about what determines the balance between these two activities (transglycosylation/hydrolysis ratio). We previously obtained by directed evolution the mutants F401S and N282T of Thermus thermophilus beta-glycosidase (Ttbeta-gly, glycoside hydrolase family 1 (GH1)), which display a higher transglycosylation/hydrolysis ratio than the wild-type enzyme. In order to find the cause of these activity modifications, and thereby set up a generic method for easily obtaining transglycosidases from glycosidases, we determined their X-ray structure. No major structural changes could be observed which could help to rationalize the mutagenesis of glycosidases into transglycosidases. However, as these mutations are highly conserved in GH1 beta-glycosidases and are located around the -1 site, we pursued the isolation of new transglycosidases by targeting highly conserved amino acids located around the active site. Thus, by single-point mutagenesis on Ttbeta-gly, we created four new mutants that exhibit improved synthetic activity, producing disaccharides in yields of 68-90% against only 36% when native Ttbeta-gly was used. As all of the chosen positions were well conserved among GH1 enzymes, this approach is most probably a general route to convert GH1 glycosidases into transglycosidases.

Semi-rational approach for converting a GH1 beta-glycosidase into a beta-transglycosidase.,Teze D, Hendrickx J, Czjzek M, Ropartz D, Sanejouand YH, Tran V, Tellier C, Dion M Protein Eng Des Sel. 2014 Jan;27(1):13-9. doi: 10.1093/protein/gzt057. Epub 2013 , Nov 27. PMID:24287187^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.