THE BETA-TURN-LIKE CONFORMATION OF TRIPEPTIDES WITH C-TERMINAL PROLINE

On the ground of CD measurements we concluded recently [1] that tripep tides with C-terminal proline demonstrate at neutral and basic pH the tendency to exist in a beta-turn-like conformation. This conclusion is now confirmed by theoretical calculations (conformational energy mini mization and molecular modeling studies) performed for Lys-Arg-Pro tri peptide. The change of configuration of amino acid in position 1 of tr ipeptide does not influence this tendency to a big extent, and in posi tion 2 even enhances it. The corresponding change in position 3 howeve r, leads to the formation of inverse beta-turn-like structure