Methyl Motions in 13C-Methylated Concanavalin as Studied by 13C Magnetic Resonance Relaxation Techniques

A. D. Sherry, J. Keepers, T. L. James, J. Teherani

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

The carbon-13 spin-lattice relaxation times and nuclear Overhauser enhancements of the N∊-monomethyllysine, N∊,N∊-dimethyllysine, and Nα,Nα-dimethylalanine resonances of 13C-methylated concanavalin A have been measured at three carbon frequencies and compared to the relaxation parameters predicted by several motional models. The experimental parameters cannot be reproduced by a simple dipolar relaxation model which includes isotropic reorientation of the protein plus free internal rotational diffusion of the methyl groups but are well predicted by a wobble in a cone model which includes isotropic reorientation of the protein at 33 ns, free internal rotational diffusion of the methyl groups, and a wobble diffusion which reflects the net motion of the amino acid side chains. The analysis indicates that the methylated ∊-amino side chains exhibit only slightly more motional freedom than does the methylated N-terminal α-amino group and suggests some restriction of methyl group rotation in the dimethylamino residues.

Original languageEnglish (US)
Pages (from-to)3181-3185
Number of pages5
JournalBiochemistry
Volume23
Issue number14
DOIs
StatePublished - Jul 1984

ASJC Scopus subject areas

  • Biochemistry

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