University of the Pacific
A fourier transform proton magnetic resonance study of the molecular conformation of S-adenosyl-L-methionine
Abstract
dc:description.abstract<p>Contrary to a previous report, S-adenosyl-L-methionine (SAM) affords stable solutions in D<sub>2</sub>O and the <sup>1</sup>H NMR spectrum can be determined. Comparison with the spectra of the model compounds adenosine, L-methionine and L-methionine-S-methyl sulfonium iodide allows complete assignment of the proton resonances. Coupling constants were determined by homonuclear decoupling and graphical analysis and were confined by computer simulation.</p><p>Details of the molecular conformation were determined by application of the Karplus equation and calculation of relative rotational isomer populations. Evidence indicates that the ribose ring is puckered preferentially in the C<sub>3</sub>'-exo conformation and that the C<sub>4</sub>'-C<sub>5</sub>' bond is constrained to a rotamer in which the sulfonium center is gauche to H<sub>4</sub>'. No conformational constraints were detected for the C<sub>α</sub>-C<sub>β</sub> and C<sub>β</sub>-C<sub>α</sub> bonds of the methionine side chain. The purine ring was shown to be oriented preferentially anti by intermolecular association studies with adenosine 5'-phosphate in the presence of MN(II).</p><p>Spectra of samples of (-)S-adenosyl-L-methionine of biological origin, differing in activity, counter ion and commercial source, have consistently revealed the presence of a small amount of the (+) sulfonium diastereomer. Arguments are presented to explain the failure of previous workers to detect (+)S-adenosyl-L-methionine in biological preparations.</p>
Degree
thesis:*- Name thesis:degree_name
- Master of Science (M.S.)
- Level thesis:degree_level
- Thesis
- Discipline thesis:degree_discipline
- Graduate School
- Year dc:date.available
- 1979
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Stolowitz, Mark Lewis
- Contributors dc:contributor
-
- Michael J. Minch
Subjects
dc:subject × 3Rights
dc:rightsIdentifiers
dc:identifier.*- Repository record dc:identifier
- https://scholarlycommons.pacific.edu/uop_etds/451
- OAI identifier oai:identifier
- oai:scholarlycommons.pacific.edu:uop_etds-1450