title: Structure of the product complex of acetyl-Ala-Pro-Ala with porcine pancreatic elastase at 1.65 A resolution.
abstract: A single crystal of porcine pancreatic elastase was mounted in a thin-walled capillary and allowed to react with acetyl-Ala-Pro-Ala-paranitroanalide. Diffraction data to 1.65 A resolution were measured and the isomorphous structure was solved from the difference Fourier map. The structure contains two surprises. Two molecules of the product: acetyl-Ala-Pro-Ala molecule are bound in the extended binding site. Both molecules are bound backwards with respect to the established mode of peptide binding.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D006860:Hydrogen Bonding; D009842:Oligopeptides; D010196:Pancreatic Elastase; D011487:Protein Conformation; D013552:Swine; D014961:X-Ray Diffraction
chemical_list: D009842:Oligopeptides; C051030:N-acetyl-alanyl-prolyl-alaninamide; D010196:Pancreatic Elastase