Metal complexes binding

Macropolycyclic ligands, 2,942 classification, 2,917 metal complexes binding sites, 2, 922 cavity size, 2,924 chirality, 2, 924 conformation, 2,923 dimensionality, 2, 924 electronic effects, 2, 922 shaping groups, 2,923 structural effects, 2,922 molecular cation complexes, 2,947 molecular neutral complexes, 2,952 multidentate, 2,915-953 nomenclature, 2,920 Macro tetrolide actins metal complexes, 2,973 Macrotricycles anionic complexes, 2,951 cylindrical... 

Tris(phenanthroline) complexes of ruthenium(II), cobalt(III), and rhodium(III) are octahedral, substitutionally inert complexes, and as a result of this coordina-tive saturation the complexes bind to double-helical DNA through a mixture of noncovalent interactions. Tris(phenanthroline) metal complexes bind to the double helix both by intercalation in the major groove and through hydrophobic association in the minor groove. " " Intercalation and minor groove-binding are, in fact, the two most common modes of noncovalent association of small molecules with nucleic acids. In addition, as with other small molecules, a nonspecific electrostatic interaction between the cationic complexes and the DNA polyanion serves to stabilize association. Overall binding of the tris(phenanthroline) complexes to DNA is moderate (log K = 4)." ... 

A great diversity exists in the design of nucleic acid probes upon transition metal chemistry in part because of the abundance of different binding interactions to nucleic acids that may be exploited. Metal complexes bind to DNA through both covalent and noncovalent modes as illustrated in Fig. 2. 

Ru(TMP)3] A distinctive characteristic of the A conformation is its shallow and wide minor-groove surface. Tris(phenanthroline)metal complexes bind to DNA both through intercalation in the major groove and through a surface-bound interaction in the minor groove (18-20) (see above). It is this surface-bound interaction that has been exploited in the construction of a complex, a derivative of tris(phenanthroline)ruthenium(II) that selectively targets A-form helical structures (30, 75). 

Metal cofactors do not always bind to the enzyme but rather bind to the primary substrate. The resulting substrate-metal complex binds to the enzyme and facilitates its activity. Creatine kinase catalyses the transfer of phosphoryl groups from adenosine triphosphate (ATP), which is broken down to adenosine diphosphate (ADP). The reaction requires the presence of magnesium ions. These, however, do not bind to the enzyme but bind to ATP, forming an ATP Mg complex. It is this complex that binds to the enzyme and allows transfer of the phosphoryl group ... 

Tang, C.C., Davalian, D., Huang, P. and Breslow, R., Models for metal binding sites in zinc enzymes. Syntheses of Tris[4(5) imidazoyl]carbinol (4-TIC), Tris(2-imidazolyl)carbinol (2-TIC), and related hgands, and studies on metal complex binding constants and spectra, /. Am. Chem. Soc., 1978,100,3918-3922. 

Since many metal complexes bind to DNA, those that show luminescence in fluid media have the potential to act as probes of biological structure. Such a feature is particularly useful if the luminescent probe is site specific on the DNA chain. Complexes that can be chemically modified at the ligand periphery, or whose photophysical properties are sensitive to medium effects, have the best potential for use in biological applications. 

White, J. R. Streptonigrin-Transition Metal Complexes Binding to DNA and Biological Activity. Biochem. Biophys. Res. Comm. 77, 387 (1977). 

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