Conformationally constrained chemotactic peptide analogs of high biological activity

Abstract

The stereochemically constrained chemotactic peptide analogs, formylmethionyl‐α‐aminoisobutyrylphenylalanine (formyl‐Met‐Aib‐Phe‐OH) and formylmethionylcycloleucinylphenylalanine (formyl‐Met‐Cyl‐Phe‐OH) are highly effective in inducing lysosomal enzyme release from rabbit neutrophils. NMR studies of the Aib² analog in (CD₃)₂SO favor a folded conformation in which the Phe NH group is inaccessible to solvent. Intramolecularly hydrogen‐bonded conformations involving a Met‐Aib‐β‐turn or a γ‐turn centered at Aib² are considered. The results suggest that folded conformations may allow highly active interactions with the neutrophil formylpeptide receptor.