Carbonic anhydrases binding sites

Other reports concerning chemically modified amino acid as metal chelating agents used for the carbonic anhydrase active site model reconstruction are in close agreement with the small contribution of Zn(II) binding to the proton chemical shift variation discussed above. NMR experiments carried out in DMSO-rfg, at 300 K, and the observed... 

Carbonic anhydrase an insight into the zinc binding site and into the active cavity through metal substitution. I. Bertini, C. Luchinat and A. Scozzafava, Struct. Bonding (Berlin), 1982, 48, 46-92 (296). 

Bertini I, Luchinat C, Scozzafava A (1982) Carbonic Anhydrase An Insight into the Zinc Binding Site and into the Active Cavity Through Metal Substitution. 48 45-91 Bertrand P (1991) Application of Electron Transfer Theories to Biological Systems. 75 1-48 Bill E, see Trautwein AX (1991) 78 1-96 Bino A, see Ardon M (1987) 65 1-28 Blanchard M, see Linares C (1977) 33 179-207 Blasse G, see Powell RC (1980) 42 43-96... 

Bertini, /., Luchinat, C., Scozzafava, A. Carbonic Anhydrase An Insight into the Zinc Binding Site and into the Active Cavity Through Metal Substitution. Vol. 48, pp. 45-91. 

B34. Brady, H. J. M., Sowden, J. C Edwards, M., Lowe, N., and Butterworth, P. H. W Multiple GF-1 binding sites flank the erythroid specific transcription unit of the human carbonic anhydrase I gene. FEBS Lett. 257,451-456 (1989). 

Figure 24 shows a possible CO2 diffusion pathway into the carbonic anhydrase II active site, and Fig. 25 shows the binding of CO2 in the hydrophobic pocket (Liang and Lipscomb, 1990). Also in Fig. 25 is the binding of CO2 in this pocket as independently calculated by Merz (1990,... 

The engineering of zinc-binding sites in a-helical peptides, where metal binding stabilizes protein tertiary structure, has been reported by Handel and DeGrado (1990). In these experiments zinc-binding sites are incorporated into a dimeric helix-loop—helix peptide (H3 2) and a protein composed of four helices connected by three short loop sequences (H3 4). a model of one subunit of the H3 2 dimer is found in Fig. 47. In addition to metal complexation by two histidine residues at positions n and n+4 of one a helix, the metal is coordinated by a third histidine residue of an adjacent a helix. The composition of the zinc coordination polyhedron is like that of carbonic anhydrase (i.e., Hiss), and spectroscopic results suggest that all three histidine residues are involved in zinc complexation. This work sets an important foundation... 

The zinc-binding site of carbonic anhydrase serves as a structural paradigm for the incorporation of a de novo zinc-binding site in an antibody (Iverson a/., 1990 Roberts cf a/., 1990 Tainer and Roberts, 1990). Because individual antibody light- and heavy-chain libraries can be com-... 

Thus although a protein can be made very specific for a particular metal, if it has a fold that generates matching properties to those possessed by the cation (e.g., carbonic anhydrase), this degree of matching is not required for the removal of heavy metals as they have such high binding constants to unconstrained sites. Clearly, there is a competition between two types of site for two metal ions ... 

XH NMR data of copper-carbonic anhydrase (CuCA) complexes in the presence of different anions indicated that water is present in the coordination sphere along with the anions (137). The three histidines, the anion, and the coordinated water molecule arrange themselves to maintain essentially a SQPY. His-94 would be in the apical position of the SQPY and two other histidine residues (His-96 and His-119) along with the anion and the coordinated water are positioned in the basal plane. Most likely the anion is present in the hydrophobic pocket or in the site and the coordinated water molecule is present in the C site or the hydrophilic binding site. 

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