Aliphatic groups of sperm whale myoglobin: 13C NMR study.
- 1 March 1979
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 76 (3) , 1059-1063
- https://doi.org/10.1073/pnas.76.3.1059
Abstract
The aliphatic region of the 13C NMR spectrum of sperm whale cyanoferrimyoglobin was examined at 67.9 MHz. Fifty partially resolved or well-resolved resonances, representing at least 1/2 of the aliphatic C in the molecule, are observed in the spectral region from 9-29 ppm downfield of tetramethylsilane. Analyses of the spin lattice relaxation times (T1) and nuclear Overhauser enhancements for these resonances reveal considerable motional freedom of the aliphatic side chains. In the spectral region from 9-15 ppm, 8 single C resonances are observed and tentatively assigned to C.delta.1 of 8 of the 9 isoleucine residues. In at least 5 cases the reorientational motion of the isoleucine side chains could not be characterized solely by rotation of the C.delta.1 methyl groups. The simplest model consistent with the data is a restricted diffusion model with 2 degrees of internal rotation. In light of the packing densities within the myoglobin molecule these results imply concerted motions of the buried aliphatic residues.This publication has 25 references indexed in Scilit:
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