Metal-Binding Sites in Proteins

The experimental observation that there is a high probability that the metal ion lies in the plane of a neighboring carboxylate ion provides a mechanism for 

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Tainer, J.A., Roberts, V.A. and Getzoff, E D. (1991) Metal binding sites in Proteins. 

Table 11 Metal Binding Sites in Proteins Established by X-ray Crystallography...

Sugai et al. (1988), Nitta and Sugai (1989), and Acharya et al. (1991) have discussed the evolution of metal binding sites in proteins. We leave... 

FIGURE 17.11. Probes of metal-binding sites in proteins, deduced from studies of crystal structures of small molecules. Shown are likely in-plane sites for a metal ions with respect to a carboxyl group or an imidazole. 

As with histidine, cysteine is a major metal binding site in proteins. Penicillamine (j8, -di-methylcysteine), a degradation product of penicillin, finds use as a therapeutic chelating agent (see Volume 6, Chapter 62.2). Both Cys and Pen have three dissociable protons (pAT values approximately 2, 8 and 10) with Pen being the slightly more basic. Both amino acids undergo oxidation to the disulfide form (equation 6), a reaction which is catalyzed by metal ions, notably Cu and Fe . 

The first structural elucidation of a naturally occurring vanadium compound has been achieved. Amavadine, which has been isolated from the fly Amanita muscaria, has been shown by degradative, synthetic, and spectroscopic studies to have the structure (32) (p.54). The use of the vanadyl group as a new spectroscopic probe of metal binding sites in proteins has been demonstrated by its incorporation into insulin. E.s.r., optical, and i.r. spectra of the protein-bound have indicated that it is held on two types of site the co-ordination geometry about the metal was determined in each case. This approach should be valuable in the study of other metalloproteins. ... 

Lu Y. Valentine J.S., 1997, Engineering metal-binding sites in proteins. Curr Opin Struct Biol 7 495-500. Nayal, M. Di Cera, E., 1994, Predicting Ca(2+)-binding sites in proteins. Proc Natl Acad Sci USA, 91(2) 817-21. 

Regan, L. 1993, The design of metal-binding sites in proteins.. 4/otm Rev Biopl s Biomol Struct, 22 257-87. Regan, L., 1995, Protein design novel metal-binding sites. Trends Biochem Set, 20(7) 280-5. 

Rare Earth Ion as Probe for Metal Binding Sites in Proteins... 

Besides direct probing, another approach utilized to study metalloproteins is the use of nuclear resonance of metal nuclei to probe the metal binding sites in proteins and many sueh investigations were eondueted upon Zn(II), Ca (II), and Cu(I) metalloproteins. ... 

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