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Mutant D416A of the CELLOBIOHYDROLASE CEL6A FROM HUMICOLA INSOLENS in complex with methyl-cellobiosyl-4-deoxy-4-thio-beta-D-cellobiosideMutant D416A of the CELLOBIOHYDROLASE CEL6A FROM HUMICOLA INSOLENS in complex with methyl-cellobiosyl-4-deoxy-4-thio-beta-D-cellobioside
Structural highlights
FunctionGUX6_HUMIN Plays a central role in the recycling of plant biomass. The biological conversion of cellulose to glucose generally requires three types of hydrolytic enzymes: (1) Endoglucanases which cut internal beta-1,4-glucosidic bonds; (2) Exocellobiohydrolases that cut the dissaccharide cellobiose from the non-reducing end of the cellulose polymer chain; (3) Beta-1,4-glucosidases which hydrolyze the cellobiose and other short cello-oligosaccharides to glucose.[1] Evolutionary Conservation![]() Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe enzymatic degradation of cellulose continues to be one of the most important enzyme-catalysed reactions. Glycoside hydrolases from family GH-6 hydrolyse cellulose with inversion of the configuration of the anomeric carbon. Whilst the catalytic proton donor has been clearly identified (Asp226 in Humicola insolens Cel6A), the identification and even the existence of a potential Bronsted base remains unclear. Equally controversial is the role of surface-loop flexibility. Here, the structure of the D416A mutant of the H. insolens cellobiohydrolase Cel6A in complex with a non-hydrolysable thiooligosaccharide methyl cellobiosyl-4-thio-beta-cellobioside at 1.9 A resolution is presented. Substrate distortion in the -1 subsite, to a (2)S(0) skew-boat conformation, is observed, similar to that seen in the analogous Trichoderma reesei Cel6A structure [Zou et al. (1999), Structure, 7, 1035-1045], but the active-centre N-terminal loop of the H. insolens enzyme is found in a more open conformation than described for previous structures. Structure of the Humicola insolens cellobiohydrolase Cel6A D416A mutant in complex with a non-hydrolysable substrate analogue, methyl cellobiosyl-4-thio-beta-cellobioside, at 1.9 A.,Varrot A, Frandsen TP, Driguez H, Davies GJ Acta Crystallogr D Biol Crystallogr. 2002 Dec;58(Pt 12):2201-4. Epub 2002, Nov 23. PMID:12454501[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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