Synthesis, NMR spectra and function of peptides with alpha-methylserine attached to the RGD sequence of osteopontin.

The three-dimensional structure of the RGD-adhesion sequence has been studied previously by means of linear and cyclic peptides. These peptides show widely differing affinities to integrins, ascribed to a strong dependence on steric factors in the receptor recognition. Insertion of alpha-methylserine next to the RGD sequence in this investigation resulted in lower affinity for both stereoisomers, and several small changes in chemical shifts and coupling constants relative to the parent serine peptide GRGDSL.