STEREOCHEMICAL STUDIES ON CYCLIC-PEPTIDES .10. CONFORMATIONAL-ANALYSIS OF HYDROGEN-BONDED CYCLIC PENTAPEPTIDES

  • 1 January 1979
    • journal article
    • research article
    • Vol. 13  (3) , 353-362
Abstract
Conformational aspects of 4 .fwdarw. 1 H-bonded cyclic pentapeptides are considered from the point of view of contact criteria and potential energy calculations. Three types of such H-bonded conformations, designated A1, A2 and B, are possible, involving some amount of strain on the bond angles. The energy of H-bonded cyclopentaglycyl is somewhat less than that of the 5-fold symmetrical conformation. The stereochemical feasibility of introducing L- and D-alanyl residues in these structures was studied and the possible types for different sequences of alanyl residues were determined. The results are discussed further in the light of the limited data available from crystal structure and NMR studies on cyclic pentapeptides.