Journal:Acta Cryst D:S2059798318014900
From Proteopedia
Structure of the AmyC GH13 alpha-amylase from Alicyclobacillus sp, reveals accommodation of starch branching points in the alpha-amylase familyJon Agirre, Olga Moroz, Sebastian Meier, Jesper Brask, Astrid Munch, Tine Hoff, Carsten Andersen, Keith S. Wilsona and Gideon J. Davies [1] Molecular Tour The complex of α-amylase from Alicyclobacillus sp. 18711 (AliC) with acarbose was solved by molecular replacement, with two molecules of AliC in the asymmetric unit, at a resolution of 2.1 Å (6gxv). The fold, as expected, is a canonical with the A, B and C domains defined approximately as A, residues 4–104 and 210–397 (in deepskyblue), B, residues 105–209 (in yellow), and C, residues 398–484 (in white). A classical Ca2+–Na+–Ca2+ [2],[3] is found at the A/B-domain interface. The structure of AliC was determined in the presence of the (colored in green). As with many (retaining) α-amylase complexes, the acarbose is observed as a transglycosylated species, here a hexasaccharide which contains two of the acarviosin disaccharide motifs. The , -4 to +2, with the expected catalytic GH13 signature triad of Asp234 (nucleophile), Glu265 (acid/base) and all disposed for catalysis, here around the 2H3 half-chair of the unsaturated cyclohexitol moiety. AliC must also be able to accommodate branching in the +2 subsite, which is consistent with the . The (6gya, oligosaccharide colored in green).
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