title: Conformation of a heptapeptide substrate bound to protein farnesyltransferase.
abstract: Protein farnesyltransferase catalyzes isoprenylation of the cysteine four residues from the C-terminus of several proteins including p21ras. Farnesylation is required for the transforming activity of Ras, and many efforts are underway to develop inhibitors of farnesyltransferase. We have used nuclear magnetic resonance spectroscopy to determine the farnesyltransferase-bound conformation of a heptapeptide substrate, KTKCVFM, which competes for the modification of p21Ha-ras in an in vitro assay. Analysis of transferred nuclear Overhauser effects reveals that the CVFM sequence of the peptide substrate is directly involved in binding to the enzyme and adopts a type I beta-turn conformation in the bound state. The present structural information should aid in the design of more effective inhibitors of the enzyme and in understanding the nature of the peptide binding site.
authors.affiliation: Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas 75235-9041.
authors.forename: S J
authors.initials: SJ
authors.lastname: Stradley
authors.forename: J
authors.initials: J
authors.lastname: Rizo
authors.forename: L M
authors.initials: LM
authors.lastname: Gierasch
mesh_terms: D019883:Alkyl and Aryl Transferases; D000595:Amino Acid Sequence; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry* / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D017433:Protein Structure, Secondary; D016283:Proto-Oncogene Proteins p21(ras) / Q000737:chemistry / Q000378:metabolism; D014166:Transferases / Q000378:metabolism*
chemical_list: D009842:Oligopeptides; D010446:Peptide Fragments; D014166:Transferases; D019883:Alkyl and Aryl Transferases; C064911:p21(ras) farnesyl-protein transferase; D016283:Proto-Oncogene Proteins p21(ras)