title: Sequence requirement for peptide recognition by rat brain p21ras protein farnesyltransferase.
abstract: We tested 42 tetrapeptides for their ability to bind to the rat brain p21ras protein farnesyltransferase as estimated by their ability to compete with p21Ha-ras in a farnesyltransfer assay. Peptides with the highest affinity had the structure Cys-A1-A2-X, where positions A1 and A2 are occupied by aliphatic amino acids and position X is occupied by a COOH-terminal methionine, serine, or phenylalanine. Charged residues reduced affinity slightly at the A1 position and much more drastically at the A2 and X positions. Effective inhibitors included tetrapeptides corresponding to the COOH termini of all animal cell proteins known to be farnesylated. In contrast, the tetrapeptide Cys-Ala-Ile-Leu (CAIL), which corresponds to the COOH termini of several neural guanine nucleotide binding (G) protein gamma subunits, did not compete in the farnesyl-transfer assay. Inasmuch as several of these proteins are geranylgeranylated, the data suggest that the two isoprenes (farnesyl and geranylgeranyl) are transferred by different enzymes. A biotinylated heptapeptide corresponding to the COOH terminus of p21Ki-rasB was farnesylated, suggesting that at least some of the peptides serve as substrates for the transferase. The data are consistent with a model in which a hydrophobic pocket in the protein farnesyltransferase recognizes tetrapeptides through interactions with the cysteine and the last two amino acids.
authors.affiliation: Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas 75235.
authors.forename: Y
authors.initials: Y
authors.lastname: Reiss
authors.forename: S J
authors.initials: SJ
authors.lastname: Stradley
authors.forename: L M
authors.initials: LM
authors.lastname: Gierasch
authors.forename: M S
authors.initials: MS
authors.lastname: Brown
authors.forename: J L
authors.initials: JL
authors.lastname: Goldstein
mesh_terms: D019883:Alkyl and Aryl Transferases; D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000201:enzymology*; D006801:Humans; D007202:Indicators and Reagents; D007700:Kinetics; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000138:chemical synthesis / Q000494:pharmacology*; D011485:Protein Binding; D051381:Rats; D013329:Structure-Activity Relationship; D014166:Transferases / Q000037:antagonists & inhibitors*
chemical_list: D007202:Indicators and Reagents; D009842:Oligopeptides; D014166:Transferases; D019883:Alkyl and Aryl Transferases; C064911:p21(ras) farnesyl-protein transferase