Circular dichroism and conformational analysis of the membrane‐modifying peptide ‐<i>N</i>‐<i>t</i>‐Boc‐(Aib‐<scp>L</scp>‐Ala)₅‐Gly‐Ala‐Aib‐Pro‐Ala‐Aib‐Aib‐Glu‐(OBzl)‐Gln‐OMe with respect to alamethicin

Abstract

Abstract The conformational analysis of the CD spectrum is reported for the synthetic and membrane‐modifying nonadecapeptide analog of alamethicin N ‐ t ‐Boc‐(Aib‐ L ‐Ala) 5 ‐Gly‐Ala‐Aib‐Pro‐Ala‐Aib‐Aib‐Glu(OBzl)‐ Gln‐OMe. The CD data are evaluated according to three different methods and are discussed with respect to those obtained from natural alamethicin and suitable models such as N ‐ t ‐Boc‐(Aib‐ L ‐Ala) 7 ‐OPOE, fragments of the synthetic nonadecapeptide, and the hexadecapeptide N ‐ t ‐Boc‐(Aib‐ L ‐Ala) 5 ‐Pro‐Ala‐Aib‐Aib‐Glu(OBzl)‐Gln‐OMe. The synthetic nonadecapeptide with the longer helical region exhibits membrane activities comparable to those of alamethicin, whereas the hexadecapeptide with the shorter helix is inactive.