The Crystal Structure of Beta-Glucosidase from Bacillus Circulans Sp. Alkalophilus: Ability to Form Long Polymeric Assemblies
Hakulinen, N., Paavilainen, S., Korpela, T., Rouvinen, J.(2000) J Struct Biol 129: 69
- PubMed: 10675298 
- DOI: https://doi.org/10.1006/jsbi.1999.4206
- Primary Citation of Related Structures:  
1QOX - PubMed Abstract: 
Family 1 of glycosyl hydrolases is a large and biologically important group of enzymes. A new three-dimensional structure of this family, beta-glucosidase from Bacillus circulans sp. alkalophilus is reported here. This is the first structure of beta-glucosidase from an alkaliphilic organism. The model was determined by the molecular replacement method and refined to a resolution of 2.7 A. The quaternary structure of B. circulans sp. alkalophilus beta-glucosidase is an octamer and subunits of the octamer show a similar (beta/alpha)(8) barrel fold to that previously reported for other family 1 enzymes. The crystal structure suggested that Cys169 in the active site is substituted. The Cys169 is located near the putative acid/base catalyst Glu166 and it may contribute to the high pH optimum of the enzyme. The crystal structure also revealed that the asymmetric unit contains two octamers which have a clear binding interaction with each other. The ability of the octamers to link with each other suggested that beta-glucosidase from Bacillus circulans sp. alkalophilus is able to form long polymeric assemblies, at least in the crystalline state.
Organizational Affiliation: 
Department of Chemistry, University of Joensuu, Joensuu, 80101, Finland.