The effect of homologous amino acid replacement on the conformation of oligopeptides. II. Synthesis of co-oligopeptides containing methionine and glycine

The synthess of 18 co-oligopeptides of L -methionine and glycine is reported. A series of oligomers, Boc-Gly-Met_n-OMe (n = 1–6), and six hexamers-containing five methionyl and one glycyl residue were synthesized using the mixed anhydride procedure. Polarimetric studies give evidence that oligomers in the Boc-Gly-Met_n-Ome series are essentially disordered in hexafluoroacetone sesquihydrate but begin forming secondry structures at n > 4 in trifluorethanol. Difference in the molar rotation values found for the six hexamers in hexafluoroacetone sesquihydrate may indicate that these compounds, while primirily disordered, are present in slightly different conformations.