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Publication Abstract from PubMed

Exoglucanase/cellobiohydrolase (EC 3.2.1.176) hydrolyzes a beta-1,4-glycosidic bond from the reducing end of cellulose and releases cellobiose as the major product. Three complex crystal structures of the glycosyl hydrolase 48 (GH48) cellobiohydrolase S (ExgS) from Clostridium cellulovorans with cellobiose, cellotetraose and triethylene glycol molecules were solved. The product cellobiose occupies subsites +1 and +2 in the open active-site cleft of the enzyme-cellotetraose complex structure, indicating an enzymatic hydrolysis function. Moreover, three triethylene glycol molecules and one pentaethylene glycol molecule are located at active-site subsites -2 to -6 in the structure of the ExgS-triethylene glycol complex shown here. Modelling of glucose into subsite -1 in the active site of the ExgS-cellobiose structure revealed that Glu50 acts as a proton donor and Asp222 plays a nucleophilic role.

Structures of exoglucanase from Clostridium cellulovorans: cellotetraose binding and cleavage.,Tsai LC, Amiraslanov I, Chen HR, Chen YW, Lee HL, Liang PH, Liaw YC Acta Crystallogr F Struct Biol Commun. 2015 Oct 1;71(Pt 10):1264-72. doi:, 10.1107/S2053230X15015915. Epub 2015 Sep 23. PMID:26457517^[1]

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