A PEPTIDE INHIBITOR OF CHOLESTERYL ESTER TRANSFER PROTEIN IDENTIFIED BY SCREENING A BACTERIOPHAGE DISPLAY LIBRARY

We screened a bacteriophage display library of random decapeptides to identify peptide inhibitors of cholesteryl ester transfer protein (CET P). After affinity selection against CETP, bacteriophage-infected Esch erichia coli were plated at clonal density and 36 random clones were i solated. Analysis of the relevant portion of the bacteriophage DNA fro m a group of 12 clones that had a relatively high affinity for CETP re vealed that the corresponding amino acid sequences of the displayed pe ptides exhibited an... Xaa-Arg-Met-Arg-Tyr-Xaa... composite motif. Bas ed on those results, decapeptides from this group were synthesized and one of them, DP1 (NH2-VTWRMWYVPA-COOH), inhibited CETP-catalyzed tran sfer of cholesteryl esters and triglycerides. Amino-and carboxy-termin al truncations of DP1 demonstrated that the original decapeptide could be reduced to a pentapeptide without loss of either its ability to bi nd to CETP or its ability to inhibit CETP-mediated lipid transfer. Tha t pentapeptide, NH2-WRMWY-COOH (WRMWY, PNU-107368E), binds directly to CETP and its inhibition is consistent with that of a competitive inhi bitor of CETP with a K-i of 164 mu M. WRMWY or modified versions of th is peptide may be useful in studying the interactions between CETP and plasma lipoproteins. (C) Munksgaard 1998.