Studies on the structure and function of hemeproteins that use advantage of introduction of fluoroalkyl groups

血红素蛋白的功能调节被认为是通过血红素的电子结构和附近氨基酸残基提供的环境来实现的。在本研究中，我将吸电子的氟(F)和全氟甲基(CF3)基团(S)取代为吡咯、卟啉和血红素侧链(S)，以获得血红素电子结构的较大变化，以阐明结构与功能之间的关系。为了定量评价F和CF3取代对高铁血红蛋白血红素铁原子电子密度的影响，我测量了高铁蛋白的~(19)F-核磁共振谱和高铁蛋白的“酸碱转变”平衡常数(PKa)。我已经证实，在血红素侧链上引入F或CF3基团(S)会导致血红素铁原子的电子密度降低，进而降低血红素蛋白的O2亲和力。

Functional regulation of hemeprotein is thought to be achieved through electronic structure of heme, and heme environment furnished by nearby amino acid residues. In this study, I have performed substitution of electron-withdrawing fluoro (F) and perfluoromethyl (CF_3) group(s) as pyrrole, porphyrin and heme side chain(s) to obtain large alteration of the heme electronic structure in order to elucidate the relationship between the structure and function. I have measured the ^<19>F-NMR, and the equilibrium constant (pKa) of the "acid-alkaline transition" in metmyoglobin in order to quantitatively assess the effects of the F and CF_3 substitutions for the electron density of heme Fe atom of the hemeprotein. I have confirmed that the introduction of F or CF_3 group(s) to the heme side chain(s) leads to a decrease in the electron density of the heme Fe atom, which in turn decreases the O_2 affinity of hemeprotein.