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Methyl dynamics in crystalline amino acids: MD and NMR
Article first published online: 12 MAY 2003
DOI: 10.1002/jcc.10263
Copyright © 2003 Wiley Periodicals, Inc.
1096-987X/asset/cover.gif?v=1&s=4429aac2462ebd499c13b3d7fe983679c5767778 "Journal of Computational Chemistry")
Additional Information
How to Cite
Chatfield, D. C., Augsten, A., D'Cunha, C. and Wong, S. E. (2003), Methyl dynamics in crystalline amino acids: MD and NMR. Journal of Computational Chemistry, 24: 1052–1058. doi: 10.1002/jcc.10263
Publication History
- Issue published online: 12 MAY 2003
- Article first published online: 12 MAY 2003
- Manuscript Accepted: 6 JAN 2003
- Manuscript Received: 7 OCT 2002
Funded by
- National Institutes of Health. Grant Number: GM08205
- Abstract
- Article
- References
- Cited By
Keywords:
- methyl rotation;
- crystalline amino acids;
- MD simulation;
- MD/NMR;
- correlation time
Graphical Abstract
Abstract
Correlation times for rotation of deuterated methyls in crystalline leucine, valine, and cyclo-L-alanyl-L-alanine are calculated with molecular dynamics and compared with NMR data. The simulations distinguish between methyls having different steric environments in the crystal, yielding correlation times differing by a factor of up to 30 for methyls within a given crystal. MD and NMR correlation times agree to within a factor of 2. However, averaging over nonequivalent methyls can yield correlation functions that, although actually multiexponential, are well fit by single exponentials. This may have significance for interpreting NMR data; previous NMR data did not distinguish between the methyls in these crystals. Adiabatic rotational barriers calculated with the X-ray structure differ from effective barriers during simulation by up to ±1 kcal/mol; the difference indicates that dynamical effects have a significant role in determining rotational correlation times. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 1052–1058, 2003