NMR Approaches to the Characterization of the Interaction of Metal Ions with Proteins
A general interest of our laboratory is the structure, function and biological role of calcium-binding proteins. Calcium ions are very important in the regulation of a wide variety of biological processes. One such process is contractility. The contraction of mammalian skeletal and cardiac muscle is regulated by the level of calcium ions present and the interaction of calcium ions with several proteins. This occurs in the following fashion. The nerve impulse releases calcium ions from the sarcoplasmic reticulum membrane which surrounds the muscle fibers. The increased intracellular calcium level then results in the interaction of calcium with the calcium-specific sites of the thin filament protein, troponin-C. This turns on the muscle. The calcium then migrates to parvalbumin, a soluble protein whose affinity for calcium ions is very high. Since this turns the contraction off, parvalbumin is referred to as a soluble relaxing factor. Eventually, the calcium is pumped back into the sarcoplasmic reticulum by the SR Ca+2 ATPase where it is bound in high concentration to the protein calsequestrin. This process thus involves the interaction of calcium with at least five proteins or membrane channels with varying affinities for calcium.
KeywordsStability Constant Fractional Change Sarcoplasmic Reticulum Membrane Spectroscopic Change Doublet Resonance
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- Corson, D. C., Williams, T. C., and Sykes, B. D., 1983, Biochem. 23:5882.Google Scholar
- Ferguson-Miller, S., and Koppenol, W. H., 1981, TIBS 6: IV.Google Scholar
- Kretzinger, R. H., and Nockolds, C. E., 1973, J. Biol. Chem. 248:3313.Google Scholar
- Shelling, J. G., and Sykes, D. B., 1985, J. Biol. Chem. 260:00000.Google Scholar
- Vogel, H. J., Drakenburg, T., and Forsen, S., in: NMR of Newly Accessible Nuclei, P. Laszlo, ed., Academic Press, N.Y. 157 (1983).Google Scholar
- Williams, T. C., Corson, D. C., Oikawa, K., McCubbin, W. D., Key, C. M., and Sykes, B. D., Biochem. submitted.Google Scholar