Conformation of a model peptide of the tandem repeat decapeptide in mussel adhesive protein by NMR and MD simulations.

The conformation of a model peptide (Ala-Lys-Pro-Ser-Tyr-Hyp-Hyp-Thr-Tyr-Lys) of the tandem repeat decapeptide sequence of Mytilus edulis foot protein-1 (mefp-1) has been studied by 1H and 13C 2D-NMR in three diverse media-DMSO-d6, water (pH 3.5) and 40% hexafluoroacetone (HFA). Various NMR parameters that were used to deduce the secondary structure were chemical shift (1H and 13C) temperature coefficients of NH chemical shifts, 3J(NH alpha) coupling constants and the pattern of intra and inter-residue NOEs. Molecular dynamics simulations making integral use of the NMR data shows that the conformation of the peptide is conserved in all the three media. The structure in the three solvents is best defined as a left-handed polyproline II helix (PPII).