Chemotactic peptides: fMLF-OMe analogues incorporating proline–methionine chimeras as N-terminal residue

Abstract The new fMLF analogues 1 – 4 , incorporating chimeric S -proline–methionine residues (namely the homochiral cis -4( S )-methylthio-( S )-proline ( 10 ) and the heterochiral trans -4( R )-methylthio-( S )-proline) ( 17 ) in place of the native S -methionine, have been prepared; their solution conformation and activity as agonists or antagonists of formylpeptide receptors have been studied. In addition to peptides 1 – 4 , which maintain the Met γ-thiomethyl-ether function, the analogues Boc-PLF-OMe ( 18 ) and For-PLF-OMe ( 19 ) devoid, as compared with 1 – 4 , of position 1 side chain, have been synthesized and their activity examined.