期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1971
卷号：68
期号：6
页码：1199-1202
DOI：10.1073/pnas.68.6.1199
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The 220 MHz spectrum of the cyclic nonapeptide Phe-Phe-Leu-Ile-Ile-Leu-Val-Pro-Pro (all L), designated cyclolinopeptide A, is analyzed by decoupling, exchange of peptide NH protons with deuterium, and measurement of the temperature dependence of the NH chemical shift. Measurement of the NH doublet spacings gives values of JN[α], the vicinal coupling of [α]-CH and NH protons of specific amino acid residues. These in turn provide estimates of the rotation angles [unk] about the HN--C[α]H[α] bonds, which in combination with energy minimization studies, allow the determination of the conformation of the main chain. It is concluded that this polypeptide in dimethylsulfoxide solution does not contain intramolecular hydrogen bonds. Deuterium-exchange rates and temperature-dependence studies indicate that of the seven peptide NH protons, five are exposed to solvent, while two, which exchange somewhat more slowly than the others, may be situated in the interior of the ring.
