NMR studies of prebiotic polypertides.

Several polypeptides prepared by means of pyrocondensation have been the subject of structural investigations. Attention has been focused on the constitutional characterization of homo-and co-polymers containing Asp and Glu residues, whose role is essential for the formation of the so-called proteinoids. Contrary to the literature data based on chemical degradation, nmr studies show conclusively that in thermal poly-aspartic acid only beta-peptide linkages are present. This result casts serious doubt on the role thermal condensation might have played in prebiotic polypeptide syntheses.