Magnesium binding

FIGURE 8. Current model for the gating mechanism in the CorA transporter. Left closed conformation with the magnesium binding sites in the sensor occupied. Right postulated open conformation allowing ion transport into the ceU. Adapted by permission of MacmiUan Publishers Ltd. from Reference 71... 

Magnesium binding in COMT. The magnesium ligands are Aspl41, Aspl69, Asnl70, both hydroxyls of 3, 5-dinitrocatechol (DNC) and a water molecule (W). 

Electrophoretic mobility and 31P-NMR measurements were made to investigate the binding of the alkaline earth cations to membranes formed from phosphatidyl choline molecules with either saturated or unsaturated hydrocarbon chains. Calcium and magnesium bind to the same degree to membranes formed from lipids with unsaturated chains. These phosphatidylcholine molecules are present in the liquid crystalline state at all temperatures under consideration. Calcium binds more strongly than magnesium to membranes formed from lipids with saturated chains, even when the lipids are in the liquid crystalline state. The selectivity is enhanced when the temperature is lowered and the saturated chain lipids are in the gel state. 

Potts, R.O., Ford, Jr., N.C. and Fournier, M.J. (1981) Changes in the solution structure of yeast phenylalanine transfer ribonucleic acid associated with aminoacylation and magnesium binding. Biochemistry, 20, 1653-1659. 

Potter, J. D., and Gergely, J. (1975). The calcium and magnesium binding sites on troponin and their role in the regulation of myofibrillar adenosine triphosphatase. / Biol. Chem. 250, 4628-4633. 

Note that the effect of magnesium binding is larger than the first term and has the opposite sign in this case (Alberty and Goldberg, 1993). 

Romer, R., and Hach, R. (1975). tRNA conformation and magnesium binding. A study of a yeast phenylalanine-specific tRNA by a fluorescent indicator and differential melting curves. Eur.J. Biochem. 55(1), 271—284. 

Rialdi, G., Levy, J., andBiltonen, R. (1972). Thermodynamic studies of transfer ribonucleic acids. I. Magnesium binding to yeast phenylalanine transfer ribonucleic acid. Biochemistry... 

Magnesium is the fourth most abundant cation in the body after sodium, potassium, and calcium, and is the second most abundant cation in intracellular fluid after K+ Mg + is needed in many enzymatic reactions, particularly those in which ATP Mg + is a substrate. Magnesium binds to other nucleotide phosphates and to nucleic acids and is required for DNA replication, transcription, and translation. The DNA helix is stabilized by binding... 

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