Crystal structure and biological implications of a glycoside hydrolase family 55 β-1,3-glucanase from Chaetomium thermophilum

Publication date: Available online 4 May 2017
Source:Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics
Author(s): Anastassios C. Papageorgiou, Jinyin Chen, Duochuan Li
Crystal structures of a β-1,3-glucanase from the thermophilic fungus Chaetomium thermophilum were determined at 1.20 and 1.42Å resolution in the free and glucose-bound form, respectively. This is the third structure of a family 55 glycoside hydrolase (GH55) member and the second from a fungus. Based on comparative structural studies and site-directed mutagenesis, Glu654 is proposed as the catalytic acid residue. The substrate binding cleft exhibits restricted access on one side, rendering the enzyme as an exo-β-1,3-glucanase as confirmed also by thin layer chromatography experiments. A lack of stacking interactions was found at the substrate binding cleft, suggesting that interactions at positions −1, +1 and +2 are sufficient to orientate the substrate. A binding pocket was identified that could explain binding of branched laminarin and accumulation of laminaritriose.



from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2pfLLbQ
via IFTTT