1b2y

Publication Abstract from PubMed

Crystal structures of human pancreatic alpha-amylase (HPA) in complex with naturally occurring inhibitors have been solved. The tetrasaccharide acarbose and a pseudo-pentasaccharide of the trestatin family produced identical continuous electron densities corresponding to a pentasaccharide species, spanning the -3 to +2 subsites of the enzyme, presumably resulting from transglycosylation. Binding of the acarviosine core linked to a glucose residue at subsites -1 to +2 appears to be a critical part of the interaction process between alpha-amylases and trestatin-derived inhibitors. Two crystal forms, obtained at different values of pH, for the complex of HPA with the protein inhibitor from Phaseolus vulgaris (alpha-amylase inhibitor) have been solved. The flexible loop typical of the mammalian alpha-amylases was shown to exist in two different conformations, suggesting that loop closure is pH-sensitive. Structural information is provided for the important inhibitor residue, Arg-74, which has not been observed previously in structural analyses.

Crystal structures of human pancreatic alpha-amylase in complex with carbohydrate and proteinaceous inhibitors.,Nahoum V, Roux G, Anton V, Rouge P, Puigserver A, Bischoff H, Henrissat B, Payan F Biochem J. 2000 Feb 15;346 Pt 1:201-8. PMID:10657258^[1]

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