Research Abstract |
1) We prepared the mercury peptide, [(Boc-Cys-Pro-Leu-Cys-Gly-Ala-OMe)Hg], and studied the coordination and conformation structures by EXAFS, ROESY, distance geometry (DG), restrained molecular dynamics (RMD) calculations, -. Comparison of the structure with that of [(Boc-Cys-Pro-Leu-Cys-OMe)Hg] revealed that both of these have a mirror type gamma-tum structure. 2) We clarified the structure of [(Boc-Cys-Pro-Leu-Cys-OMe)(S-tert-C_4H_9)Hg] by the same way as above. This study clarified that the conformation of Cys-X_2-Cys does not depend on the kinds of metal ions, but depends on the S-M-S bite angle, and the peptide conformation obtained for this compound agreed with that of the zinc binding sites of zinc finger motifs 3)We synthesized [(Boc-Cys-Pro-Leu-Cys-OMe)Zn] and [(Boc-Cys-Pro-Leu-Cys-Gly-Ala-OMe)Zn] in terms of zinc finger motifs. We studied the substitution reactions of the zinc sites of these compounds. The structure of the former was discussed by molecular orbital calculations, MD calculations, EXAFS, NMR. 4) We studied the complex formation between Boc-Glu-Thr-Ile-His-OMe and Zn^<2+> with respect to the zinc binding sites of proteases. The structural study by ROESY, RMD and MO suggested that this system generates a species which is structurally similar to the corresponding sites of proteases. 5) We de novo designed and synthesized an artificial protein, which is capable of incorporating multiple porphyrins into its His sites, on the basis of template assisted synthetic protein approach, where a picket fence porphyrin was adopted as the template. This peptide porphyrin incorporated another types of porphyrins into the His sites forming a series of trimeric aggregates, thus achieved a 12 hetero-porphyrin system.
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