XAS STUDIES OF THE STRUCTURE AND FUNCTION OF WEAK CHEMICAL INTERACTIONS IN PSEUD

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 非共价弱相互作用在生物体系中起着重要的作用。最近，我们报道了Met 16 Phe突变体的蓝铜蛋白pseudoazurin（PAz）的结构和反应性，以研究在蕨类质体蓝蛋白的不寻常结构和反应性中观察到的π-π相互作用的影响。的Met 16取代的突变体的PAz，其中几个烷基和芳香族基团被引入接近咪唑的His 81配体，已被构建和表征，以探测间接弱相互作用的活性位点的结构和功能的影响。Met 16 Tyr、Met 16 Trp和Met 16 Phe突变体的电子吸收光谱表明，与野生型PAz的A460/A594 = 0.46相比，A460/A598 = ~0.3的比率较小。Met 16 Phe、Met 16 Tyr和Met 16 Trp突变体的EPR谱表明轴向信号贡献增强。在本研究中，我们将通过XAS技术研究Met 16 X pseudoazurin突变蛋白活性位点的详细结构和电子结构信息。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Non-covalent weak interactions play important roles in biological systems. Very recently, we reported the structure and reactivity of the Met16Phe mutant of the blue copper protein pseudoazurin (PAz) to investigate the effects of the pi-pi interaction observed in the unusual structure and reactivity of fern plastocyanin. The Met16 substituted mutants of PAz, in which several alkyl and aromatic groups are introduced close to the imidazole of the His81 ligand, have been constructed and characterized in order to probe the effects of the indirect weak interaction on the structure and function of the active site. Electronic absorption spectra of Met16Tyr, Met16Trp, and Met16Phe mutants indicated the smaller ratio of A460/A598 = ~0.3 as compared to that of wild type PAz, A460/A594 = 0.46. EPR spectra of the Met16Phe, Met16Tyr and Met16Trp mutants indicated the enhancement of the axial signal contribution. In this proposal, we will investigate the detailed structural and electronic structural information at the active site of Met16X pseudoazurin mutant proteins by XAS.