Comparison of compuational methods for simulating nuclear Overhauser effects in NMR spectroscopy

✍ Scribed by Mark J. Forster

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 922 KB
• Volume: 12
• Category: Article
• ISSN: 0192-8651
• DOI: 10.1002/jcc.540120303

✦ Synopsis

Various algorithms for solving the Solomon equations describing nuclear Overhauser effects (noes) in NMR spectroscopy have been compared. The applicability of the eigenvalue/eigenvector and the numerical integration approaches have been investigated. The eigenvalue/eigenvector approach is not a computationally efficient means of simulating nOe experiments in which a saturating radiofrequency field is applied during the time course. For experiments in which noes develop in the absence of an RF field, this approach should only be used in simulating a full NOESY spectrum. Integration schemes have been found to be more efficient at simulating nOe experiments in which the nOe evolves in the presence of a saturating field, at simulating a partial set of initial perturbation experiments and at simulating a few rows or columns in a NOESY spectrum. Various integration schemes were applied to a two-spin system for which an analytic solution is available and to a model B-DNA oligonucleotide hexamer. The previously unused Taylor series algorithm was found to be superior to the Euler, midpoint, and fourth-order Runge-Kutta methods with regard to integration accuracy/computation time. An adaptive step size control routine for the Taylor series integration scheme was developed. Integration schemes can be speeded up in a simple fashion by introducing a distance cutoff for the dipolar interaction. Using a cutoff of 8 A the Taylor series algorithm was able to compute the NOESY spectrum more rapidly than the eigenvalue/eigenvector algorithm for large spin systems at short mixing times. At longer mixing times the eigenvalue/eigenvector approach becomes the more efficient scheme.