The effect of hydration on the dynamics of trimethoprim bound to dihydrofolate reductase. A deuterium NMR study.
To determine the effect of hydration on the dynamics of a protein complex, we used deuterium nuclear magnetic resonance (NMR) techniques to examine a trimethoprim (TMP)/E. coli dihydrofolate reductase (DHFR) complex in its lyophilized, partially hydrated, polycrystalline, and ammonium sulfate-precipitated states. The results indicate that TMP is rigid in the lyophilized powder state. The dynamic behavior could be restored by partial rehydration. At 30 wt% hydration the deuterium spectrum of the partially hydrated sample was indistinguishable from that of the polycrystalline and ammonium sulfate-precipitated samples, suggesting that the structure of the protein/TMP complex is similar in the three physical states. Furthermore, we found that the para- and meta-methoxyl groups have very different dynamical behavior.
Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, Rep. of China.
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Yang
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Huang
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Huang
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Gelbaum
D055592:Biophysical Phenomena; D001703:Biophysics; D004926:Escherichia coli / Q000201:enzymology; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D013762:Tetrahydrofolate Dehydrogenase / Q000737:chemistry / Q000378:metabolism*; D014295:Trimethoprim / Q000378:metabolism*; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
D046911:Macromolecular Substances; D014867:Water; D014295:Trimethoprim; D013762:Tetrahydrofolate Dehydrogenase