The crystal structure of a 2-fluorocellotriosyl complex of the Streptomyces lividans endoglucanase CelB2 at 1.2 angstrom resolution

G Sulzenbacher, L F Mackenzie, K S Wilson, S G Withers, C Dupont, G J Davies

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Original languageEnglish
Pages (from-to)4826-4833
Number of pages8
JournalBiochemistry
Volume38
Issue number15
Publication statusPublished - 13 Apr 1999

Keywords

  • SEQUENCE-BASED CLASSIFICATION
  • X-RAY STRUCTURE
  • ACTIVE-SITE
  • TRICHODERMA-REESEI
  • MACROMOLECULAR STRUCTURES
  • MOLECULAR REPLACEMENT
  • GLYCOSYL HYDROLASES
  • CELLULOMONAS-FIMI
  • PROTEIN MODELS
  • REFINEMENT

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