Synthesis of Peptides Containing C-Terminal Esters Using Trityl Side-Chain Anchoring: Applications to the Synthesis of C-Terminal Ester Analogs of the Saccharomyces cerevisiae Mating Pheromone a-Factor.
Peptides containing C-terminal esters are an important class of bioactive molecules that includes a-factor, a farnesylated dodecapeptide, involved in the mating of Saccharomyces cerevisiae. Here, results that expand the scope of solid-phase peptide synthetic methodology that uses trityl side-chain anchoring for the preparation of peptides with C-terminal cysteine alkyl esters are described. In this method, Fmoc-protected C-terminal cysteine esters are anchored to trityl chloride resin and extended by standard solid-phase procedures followed by acidolytic cleavage and HPLC purification. Analysis using a Gly-Phe-Cys-OMe model tripeptide revealed minimal epimerization of the C-terminal cysteine residue under basic conditions used for Fmoc deprotection. (1)H NMR analysis of the unfarnesylated a-factor precursor peptide confirmed the absence of epimerization. The side-chain anchoring method was used to produce wild-type a-factor that contains a C-terminal methyl ester along with ethyl-, isopropyl-, and benzyl-ester analogs in good yield. Activity assays using a yeast-mating assay demonstrate that while the ethyl and isopropyl esters manifest near-wild-type activity, the benzyl ester-containing analog is ca. 100-fold less active. This simple method opens the door to the synthesis of a variety of C-terminal ester-modified peptides that should be useful in studies of protein prenylation and other structurally related biological processes.
Veronica
V
Diaz-Rodriguez
Department of Microbiology, University of Tennessee , Knoxville, Tennessee 37996, United States.
Elena
E
Ganusova
Todd M
TM
Rappe
Department of Microbiology, University of Tennessee , Knoxville, Tennessee 37996, United States.
Jeffrey M
JM
Becker
Mark D
MD
Distefano
D000595:Amino Acid Sequence; D001686:Biological Phenomena; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000737:chemistry*; D004151:Dipeptides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry; D010675:Pheromones / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000737:chemistry*; D013329:Structure-Activity Relationship
D004151:Dipeptides; D010455:Peptides; D010675:Pheromones; C029660:glycylphenylalanine; D003545:Cysteine