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Publication Abstract from PubMed

Recombinant Bacillus halmapalus alpha-amylase (BHA) was studied in two different crystal forms. The first crystal form was obtained by crystallization of BHA at room temperature in the presence of acarbose and maltose; data were collected at cryogenic temperature to a resolution of 1.9 A. It was found that the crystal belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 47.0, b = 73.5, c = 151.1 A. A maltose molecule was observed and found to bind to BHA and previous reports of the binding of a nonasaccharide were confirmed. The second crystal form was obtained by pH-induced crystallization of BHA in a MES-HEPES-boric acid buffer (MHB buffer) at 303 K; the solubility of BHA in MHB has a retrograde temperature dependency and crystallization of BHA was only possible by raising the temperature to at least 298 K. Data were collected at cryogenic temperature to a resolution of 2.0 A. The crystal belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 38.6, b = 59.0, c = 209.8 A. The structure was solved using molecular replacement. The maltose-binding site is described and the two structures are compared. No significant changes were seen in the structure upon binding of the substrates.

Structure of Bacillus halmapalus alpha-amylase crystallized with and without the substrate analogue acarbose and maltose.,Lyhne-Iversen L, Hobley TJ, Kaasgaard SG, Harris P Acta Crystallogr Sect F Struct Biol Cryst Commun. 2006 Sep 1;62(Pt, 9):849-54. Epub 2006 Aug 26. PMID:16946462^[1]

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