OXYTOCIN AND NEUROHYPOPHYSEAL PEPTIDES: SPECTRAL ASSIGNMENT AND CONFORMATIONAL ANALYSIS BY 220 MHz NUCLEAR MAGNETIC RESONANCE*,†
Abstract
Magnetic resonance peaks have been assigned to individual protons of the constituent amino acids in the neurohypophyseal hormone, oxytocin, and in related peptides. The assignments were made possible by operation at 220 MHz with the use of variable temperature studies, proton homonuclear spin-decoupling, and comparison of spectra of oxytocin analogs. Some of the observed chemical shifts, and NH-CHα coupling constants were studied in relation to the conformation of the hormone.
Footnotes
-
↵ ‡ To whom reprint requests should be addressed.
-
↵ * This work was supported, in part, by U.S. Public Health Service grant AM 10080 of the National Institute of Arthritis and Metabolic Diseases and by the U.S. Atomic Energy Commission.
-
↵ † Neurohypophyseal hormones are denoted in accordance with the IUPAC-IUB Tentative Rules (Biochemistry, 6, 362 (1967)) and standard abbreviations are used for amino acid residues (Biochemistry, 5, 2485 (1966)). The amino acids (except glycine) are of the L-configuration.
