# Nuclear overhauser effects as probes of peptide structure. A diagnostic for left-handed helical conformations

Ramakrishnan, C and Sukumar, M and Balaram, P (1987) Nuclear overhauser effects as probes of peptide structure. A diagnostic for left-handed helical conformations. In: Biochemical and Biophysical Research Communications, 149 (3). pp. 953-959.

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Official URL: http://dx.doi.org/10.1016/0006-291X(87)90501-8

## Abstract

The conformational dependence of the interresidue interproton distances in peptides, $C^{\alpha}_iH$ \cdots $N_{i+1}H$ and $N_iH$ \cdots $N_{i+1}H$, have been used to identify zones of sterically allowed \varphi, \psi space, where both distances are < 3\AA and expected to yield nuclear Overhauser effects (NOEs). L-residues in left-handed helical conformations are expected to yield both interresidue NOEs and also an appreciable intraresidue $N_H$\longleftrightarrow$C^{\alpha}_iH$ NOE. The effect of cutoff distances has been evaluated. Experimental results on three model peptides illustrate the utility of these NOEs in identifying L-residues at the i+2 position of Type II and I'\beta-turns. Simultaneous observation of both interresidue NOEs may also be indicative of conformational heterogeneity in specific cases, as illustrated for a single residue in a decapeptide.

Item Type: Journal Article Copyright of this article belongs to Elsevier Science. Division of Biological Sciences > Molecular Biophysics Unit 22 Feb 2005 22 Oct 2010 06:13 http://eprints.iisc.ernet.in/id/eprint/2832