Peptide Models for Type III Copper Sites in Proteins

描述(申请人提供)：建议的研究包括检测铜(I)和铜(II)在三个多肽中的结合位置，以期建立金属离子的配位环境。在项目的第一阶段，将检查在铜(I)和铜(11)离子存在和不存在的情况下制备的多肽的溶液构象，以确定铜的络合所需的构象变化的程度。用EPR、Endor、ESEEM、核磁共振和FTIR光谱进一步确定铜肽络合物中铜的结合位置。将其中两个制备的多肽与适当的铜盐以2：1的铜(I)/多肽的比例反应，以产生双铜络合物。二铜络合物将通过与分子氧的反应转化为氧加合物。用电子吸收光谱和核磁共振光谱研究了每个配体的氧络合物。将考察氧气络合物对水和其他质子性溶剂的稳定性。建议对所有氧或脱氧形式的孤立络合物进行物理研究，包括X射线结构分析。

DESCRIPTION (provided by applicant): The proposed study involves examining the binding sites of copper (I) and copper (ll) in three peptides with a view to establishing the coordination environment of the metal ion. In the first stage of the project, the solution conformation of the prepared peptides will be examined with and without the presence of copper (I) and copper (ll) ions in order to establish the extent of conformational change that is necessary for complexation of copper. The binding sites of copper in the copper-peptide complexes will be further determined with EPR, ENDOR, ESEEM, NMR and FTIR spectroscopy. Two of the prepared peptides will be reacted with an appropriate copper salt in a 2:1 copper (I)/peptide ratio in order to produce a dicopper complex. The dicopper complex will be transformed into a dioxygen adduct through reaction with molecular oxygen. The dioxygen complex for each ligand will be investigated by the use of electronic absorption spectroscopy and NMR spectroscopy. Stability of the dioxygen complex towards water and other protic solvents will be examined. Physical studies, including X-ray structural analysis, are proposed for all isolated complexes of the oxy or deoxy forms.