title: Structure of ethanol-inhibited porcine pepsin at 2-A resolution and binding of the methyl ester of phenylalanyl-diiodotyrosine to the enzyme.
abstract: An account of x-ray crystallographic studies of monoclinic porcine pepsin crystals is presented. The chain fold specific for aspartyl proteases is described in detail. As the results of 2-A refinement have shown, the actual structure is that of ethanol-inhibited pepsin. The structure, although close to those of fungal aspartyl proteases, has some specific features: one of them is an insertion near the S'1 site which restricts the position of dipeptide substrates and makes their productive binding more probable than in the fungal enzymes. 3-A resolution data on the binding of the dipeptide phenylalanyl-diiodotyrosine methyl ester are discussed.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016282:Aspartic Acid Endopeptidases; D004151:Dipeptides / Q000378:metabolism*; D010450:Endopeptidases / Q000032:analysis; D004723:Endorphins; D000431:Ethanol / Q000494:pharmacology*; D005583:Fourier Analysis; D008958:Models, Molecular; D010434:Pepsin A / Q000032:analysis* / Q000037:antagonists & inhibitors; D010446:Peptide Fragments; D011487:Protein Conformation; D013552:Swine; D014961:X-Ray Diffraction
chemical_list: D004151:Dipeptides; D004723:Endorphins; D010446:Peptide Fragments; D000431:Ethanol; C050079:lysyl-lysyl-glycyl-glutamic acid; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; D010434:Pepsin A