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Proton magnetic resonance studies of actinomycin‐related peptides containing N‐methyl groups
Author(s) -
Mauger A. B.,
Rzeszotarski W. J.,
Ford R. A.
Publication year - 1973
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270050508
Subject(s) - dipeptide , steric effects , conformational isomerism , chemistry , proton magnetic resonance , spectral line , chemical shift , lanthanide , crystallography , stereochemistry , resonance (particle physics) , peptide , reagent , methyl group , proton , nuclear magnetic resonance , molecule , group (periodic table) , organic chemistry , biochemistry , ion , physics , particle physics , astronomy , quantum mechanics
Abstract The PMR spectra of several cyclic and acyclic dipeptide derivatives representing portions of the actinomycin structure have been studied. In the spectra of the acyclic compounds temperature‐dependent duplicity resulted from the equilibration of conformers possessing cis and trans peptide bonds. The lanthanide shift reagent Eu(FOD) 3 was utilized to distinguish N‐methyl groups in the two conformations and observations were made on the steric dependence of the observed shifts. The origin of the wide variation in chemical shift of N‐methylvalyl α‐protons is discussed in relation to the conformation of actinomycin.