Comparative study of conformational behaviour of leucine and methionine enkephalinamides by 1H-nuclear magnetic resonance spectroscopy.
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Date
1988-03
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Abstract
The conformational proclivity of leucine and methionine enkephalinamides in
deuterated dimethyl sulphoxide has been investigated using proton magnetic resonance at
500 MHz. The resonances from the spin system of the various amino acid residues have
been assigned from the 2-dimensional correlated spectroscopy spectra. The temperature
variation of the amide proton shifts indicates that none of the amide proton is intramolecularly
hydrogen-bonded or solvent-shielded. The analysis of vicinal coupling constants,
3JHN.C
2
H,along with temperature coefficients and the absence of characteristic nuclear
Overhauser effect cross peaks between the NH protons reveal that there is no evidence of
the chain folding in these molecules. However, the observation of nuclear Overhauser effect
cross peaks between the NH and the CαH of the preceding residue indicates preference for
extended backbone conformation with preferred side chain orientations particularly of Tyr
and Phe in both [Leu5] - and [Met5]-enkephalinamides.
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Keywords
Enkephalinamides, nuclear magnetic resonance, structure-activity relationship, endogenous peptides, temperature coefficients
Citation
Dhingra M M, Saran Anil. Comparative study of conformational behaviour of leucine and methionine enkephalinamides by 1H-nuclear magnetic resonance spectroscopy. Journal of Biosciences. 1988 Mar; 13(1): 9-19.