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利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 非共价弱相互作用在生物体系中扮演着重要的角色。最近，我们报道了蓝铜蛋白假天青素(PAZ)的Met16Phe突变体的结构和反应性，以研究蕨类植物花青素异常结构和反应性中观察到的pi-pi相互作用的影响。为了探讨间接弱相互作用对活性中心结构和功能的影响，构建并鉴定了PAZ的Met16取代突变体，其中在His81配体的咪唑附近引入了几个烷基和芳基。Met16Tyr、Met16Trp和Met16Phe突变体的电子吸收光谱显示A460/A598=~0.3，而野生型Paz的A460/A594=0.46。Met16Phe、Met16Tyr和Met16Trp突变体的EPR谱表明轴向信号的贡献增强。在这个方案中，我们将用XAS研究Met16X假天青突变蛋白活性部位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.