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Publication Abstract from PubMed

The microbial deconstruction of the plant cell wall is a key biological process that is of increasing importance with the development of a sustainable biofuel industry. The glycoside hydrolase families GH5 (PaMan5A) and GH26 (PaMan26A) endo-beta-1,4-mannanases from the coprophilic ascomycete Podospora anserina contribute to the enzymatic degradation of lignocellulosic biomass. In this study, P. anserina mannanases were further subjected to detailed comparative analysis of their substrate specificities, active site organization and transglycosylation capacity. Although PaMan5A displays a classical mode of action, PaMan26A revealed an atypical hydrolysis pattern with the release of mannotetraose and mannose from mannopentaose resulting from a predominant binding mode involving the -4 subsite. The crystal structures of PaMan5A and PaMan26A were solved at 1.4A and 2.85A resolution, respectively. Analysis of the PaMan26A structure supported strong interaction with substrate at the -4 subsite mediated by two aromatic residues W244 and W245. The PaMan26A structure appended to its family 35 carbohydrate-binding module revealed a short and proline-rich rigid linker that anchored together the catalytic and the binding modules.

Structural and biochemical analyses of glycoside hydrolase families 5 and 26 beta-(1,4)-mannanases from Podospora anserina reveal differences upon manno-oligosaccharides catalysis.,Couturier M, Roussel A, Rosengren A, Leone P, Stalbrand H, Berrin JG J Biol Chem. 2013 Apr 4. PMID:23558681^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.