Structural highlights
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 PubMedGA (glucoamylase) hydrolyses starch and polysaccharides to beta-D-glucose. RoGA (Rhizopus oryzae GA) consists of two functional domains, an N-terminal SBD (starch-binding domain) and a C-terminal catalytic domain, which are connected by an O-glycosylated linker. In the present study, the crystal structures of the SBD from RoGA (RoGACBM21) and the complexes with beta-cyclodextrin (SBD-betaCD) and maltoheptaose (SBD-G7) were determined. Two carbohydrate binding sites, I (Trp(47)) and II (Tyr(32)), were resolved and their binding was co-operative. Besides the hydrophobic interaction, two unique polyN loops comprising consecutive asparagine residues also participate in the sugar binding. A conformational change in Tyr(32) was observed between unliganded and liganded SBDs. To elucidate the mechanism of polysaccharide binding, a number of mutants were constructed and characterized by a quantitative binding isotherm and Scatchard analysis. A possible binding path for long-chain polysaccharides in RoGACBM21 was proposed. Crystal structures of the starch-binding domain from Rhizopus oryzae glucoamylase reveal a polysaccharide-binding path.,Tung JY, Chang MD, Chou WI, Liu YY, Yeh YH, Chang FY, Lin SC, Qiu ZL, Sun YJ Biochem J. 2008 Nov 15;416(1):27-36. PMID:18588504[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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