|Title||The crystal structure of a 2-fluorocellotriosyl complex of the Streptomyces lividans endoglucanase CelB2 at 1.2 angstrom resolution|
|Publication Type||Journal Article|
|Year of Publication||1999|
|Authors||Sulzenbacher, G, Mackenzie, LF, Wilson, KS, Withers, SG, Dupont, C, Davies, GJ|
|Type of Article||Article|
|Keywords||ACTIVE-SITE, CELLULOMONAS-FIMI, GLYCOSYL HYDROLASES, MACROMOLECULAR STRUCTURES, MOLECULAR REPLACEMENT, PROTEIN MODELS, REFINEMENT, SEQUENCE-BASED CLASSIFICATION, TRICHODERMA-REESEI, X-ray structure|
Glycoside hydrolases have been classified into over 66 families on the basis of amino acid sequence. Recently a number of these families have been grouped into "clans" which share a common fold and catalytic mechanism [Henrissat, B., and Bairoch, A. (1996) Biochem. J, 316, 695-696]. Glycoside hydrolase Clan GH-C groups family 11 xylanases and family 12 cellulases, which share the same jellyroll topology, with two predominantly antiparallel beta-sheets forming a long substrate-binding cleft, and act with net retention of anomeric configuration. Here we present the three-dimensional structure of a family 12 endoglucanase, Streptomyces lividans CelB2, in complex with a 2-deoxy-2-fluorocellotrioside. Atomic resolution (1.2 Angstrom) data allow clear identification of two distinct species in the crystal. One is the glycosyl-enzyme intermediate, with the mechanism-based inhibitor covalently linked to the nucleophile Glu 120, and the other a complex with the reaction product, 2-deoxy-2-fluoro-beta-D-cellotriose. The active site architecture of the complex provides insight into the double-displacement mechanism of retaining glycoside hydrolases and also sheds light on the basis of the differences in specificity between family 12 cellulases and family 11 xylanases.
|URL||<Go to ISI>://000079918200020|