Crystallization and preliminary X-ray analysis of pig pancreatic alpha-amylase in complex with a bean lectin-like inhibitor.
Pig pancreatic alpha-amylase (PPA, E.C. 3.2. 1. 17, 496 amino-acid residues) has been crystallized as a complex with a lectin-like inhibitor from bean Phaseolus vulgaris (224 amino-acid residues for the inhibitor monomer). The hanging-drop vapour-diffusion method was used to grow crystals from solutions containing 2-methyl-2,4-pentanediol as precipitant. The crystals belong to monoclinic space group C2 with a = 152.5, b = 80.3, c = 68.8 A, beta = 91.4 and diffract to 2.9 A resolution. A molecular-replacement solution of the structure has been obtained using the refined PPA and LoLl (Lathyrus ochrus isolectin I) atomic coordinates as starting models. Low-resolution refinement of the model is underway. The analysis reveals that the functional inhibitor molecule is dimeric and interacts with two molecules of enzyme.
LCCMB-IFRCI-CNRS, Marseille, France.
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Gilles
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Rousseau
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Rougé
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Payan