2D NMR-STUDIES OF CHINESE RAPE POLLEN DOD ECAPEPTIDE

The dodecapeptide (RPP) is an active peptide, which we extracted from chinese rape pollen. The dodecapeptide enhances the activity of TNF on murine tumor cells and also shows immunopromotive activities. The pos sible conformation of the RPP, which has been previously studied by ci rcular dichroism, has been studied by one and two dimensional NMR spec troscopy. All resonance assignments were made by use of two dimensiona l correlation spectroscopy. The problem of sequential resonance assign ments was solved by using two dimensional NOE spectroscopy. The dihedr al angles of the amide planes of the RPP, were calculated from the mea sured coupling constants using Karplus equation, The temperature coeff icient and NOE in different solvents together suggest that RPP exists mainly as random coil in aqueous solution and some sections in the RPP exist as gamma-turn.