NMR studies of novel inhibitors bound to farnesyl-protein transferase.
Farnesyl-protein transferase (FPTase) catalyzes the posttranslational farnesylation of the cysteine residue located in the carboxyl-terminal tetrapeptide of the Ras oncoprotein. Prenylation of this residue is essential for the membrane association and cell-transforming activities of ras. Inhibitors of FPTase have been demonstrated to inhibit ras-dependent cell transformation and thus represent a potential therapeutic strategy for the treatment of human cancers. The FPTase-bound conformation of a tetrapeptide inhibitor, CVWM, and a novel pseudopeptide inhibitor, L-739,787, have been determined by NMR spectroscopy. Distance constraints were derived from two-dimensional transferred nuclear Overhauser effect experiments. Ligand competition experiments identified the NOEs that originate from the active-site conformation. Structures were calculated with the combination of distance geometry and restrained energy minimization. Both peptide backbones are shown to adopt nonideal reverse-turn conformations most closely approximating a type III beta-turn. These results provide a basis for understanding the spatial arrangements necessary for inhibitor binding and selectivity and may aid in the design of therapeutic agents.
Koblan
K S
KS
Department of Cancer Research, Merck Research Laboratories, West Point, Pennsylvania 19486, USA.
Culberson
J C
JC
Desolms
S J
SJ
Giuliani
E A
EA
Mosser
S D
SD
Omer
C A
CA
Pitzenberger
S M
SM
Bogusky
M J
MJ
D019883:Alkyl and Aryl Transferases; D000577:Amides / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D000595:Amino Acid Sequence; D003196:Computer Graphics; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009842:Oligopeptides / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D011485:Protein Binding; D011487:Protein Conformation; D017368:Protein Prenylation; D011994:Recombinant Proteins / Q000737:chemistry; D014166:Transferases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism
D000577:Amides; C089417:L 739750; C094720:L 739787; D009842:Oligopeptides; D011994:Recombinant Proteins; C094719:cysteinyl-valyl-tryptophyl-methionine; D014166:Transferases; D019883:Alkyl and Aryl Transferases; C064911:p21(ras) farnesyl-protein transferase