Download MendeleyThe Crystal Structures of the Open and Catalytically Competent Closed Conformation of Escherichia coli Glycogen Synthase.
Sheng, F., Jia, X., Yep, A., Preiss, J., Geiger, J.H.(2009) J Biol Chem 284: 17796-17807
- PubMed: 19244233
- DOI: https://doi.org/10.1074/jbc.M809804200
- Primary Citation of Related Structures:
2QZS, 2R4T, 2R4U, 3COP, 3D1J, 3GUH - PubMed Abstract:
Escherichia coli glycogen synthase (EcGS, EC 2.4.1.21) is a retaining glycosyltransferase (GT) that transfers glucose from adenosine diphosphate glucose to a glucan chain acceptor with retention of configuration at the anomeric carbon. EcGS belongs to the GT-B structural superfamily. Here we report several EcGS x-ray structures that together shed considerable light on the structure and function of these enzymes. The structure of the wild-type enzyme bound to ADP and glucose revealed a 15.2 degrees overall domain-domain closure and provided for the first time the structure of the catalytically active, closed conformation of a glycogen synthase. The main chain carbonyl group of His-161, Arg-300, and Lys-305 are suggested by the structure to act as critical catalytic residues in the transglycosylation. Glu-377, previously thought to be catalytic is found on the alpha-face of the glucose and plays an electrostatic role in the active site and as a glucose ring locator. This is also consistent with the structure of the EcGS(E377A)-ADP-HEPPSO complex where the glucose moiety is either absent or disordered in the active site.
Organizational Affiliation:
Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA.
