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Internet Electronic Journal of Molecular Design - IEJMD, ISSN 1538-6414, CODEN IEJMAT
| ABSTRACT - Internet Electron. J. Mol. Des. February 2003, Volume 2, Number 2, 55-69 |
A Computer Program for the Simulation of the NOE Effect in
NMR Spectroscopy, and Its Implementation into the CICADA
Conformational Search Program
Zdenek Kriz, Jaroslav Koca, and Per H. J. Carlsen
Internet Electron. J. Mol. Des. 2003, 2, 55-69
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Abstract:
Three-dimensional structure plays increasing role in the design
of molecules with predefined features. Therefore, further
development of methods that give 3-D information is necessary.
Many molecules of interest are conformationally flexible and
difficulties with interpretation of experimental (for example,
Nuclear Magnetic Resonance) data may occur. Computational
methods are promising tools that can assist to eliminate the
above problems. To begin with, however, computational
methods and computer programs must be developed that are able
to reproduce data for conformationally rigid molecules. The
previously developed computer program CICADA was used to
describe conformational Potential Energy Surfaces (PESs) of
selected molecules. The conformational flexibility of these
molecules was deduced from the PESs. Equations describing the
NMR technique termed Nuclear Overhauser Enhancement
(NOE) were used to characterize NOE for different
conformations. The computer program NOESIM for NOE
enhancement calculation has been developed. This program is
implemented as part of the CICADA computer program package.
Five different models have been implemented, tested for
relaxation rate calculation of methyl groups, and their results
compared. It is shown that NOESIM adequately predicts the
experimental NOE effects for rigid molecules. The effort in the
future will be improve its performance also for use with flexible
systems, for example, Boltzmann distribution of conformers or
flexibility of conformers. The program is available upon request
by E-mail from zdenek@chemi.muni.cz.
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