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Mode of operation and low-resolution structure of a multi-domain and hyperthermophilic endo-β-1,3-glucanase from Thermotoga petrophila

Cota, Junio, Alvarez, Thabata M., Citadini, Ana P., Santos, Camila Ramos, de Oliveira Neto, Mario, Oliveira, Renata R., Pastore, Glaucia M., Ruller, Roberto, Prade, Rolf A., Murakami, Mario T., Squina, Fabio M.
Biochemical and biophysical research communications 2011 v.406 no.4 pp. 590-594
Thermotoga, X-radiation, active sites, beta-glucans, biofuels, carbohydrate binding, drugs, enzymes, glucose
1,3-β-Glucan depolymerizing enzymes have considerable biotechnological applications including biofuel production, feedstock-chemicals and pharmaceuticals. Here we describe a comprehensive functional characterization and low-resolution structure of a hyperthermophilic laminarinase from Thermotoga petrophila (TpLam). We determine TpLam enzymatic mode of operation, which specifically cleaves internal β-1,3-glucosidic bonds. The enzyme most frequently attacks the bond between the 3rd and 4th residue from the non-reducing end, producing glucose, laminaribiose and laminaritriose as major products. Far-UV circular dichroism demonstrates that TpLam is formed mainly by beta structural elements, and the secondary structure is maintained after incubation at 90°C. The structure resolved by small angle X-ray scattering, reveals a multi-domain structural architecture of a V-shape envelope with a catalytic domain flanked by two carbohydrate-binding modules.