神经红蛋白突变体H64V与叠氮离子的作用

Interaction of Neuroglobin Mutant H64V with Azide Anion

将64位组氨酸(His64)突变为缬氨酸(Val),构建了神经红蛋白(Ngb)突变体H64V基因并进行了蛋白的表达纯化,突变使Ngb的血红素Fe由六配位结构变成五配位结构.利用光谱法研究了突变体H64V与叠氮离子(N_3^-)的相互作用.紫外-可见吸收光谱表明,H64V与N_3^-键合后其Soret带吸收峰由406 nm红移至418 nm;荧光光谱表明N_3^-可使H64V的荧光发生静态猝灭.计算得到了H64V与N_3^-键合的平衡解离常数和热力学参数.另外,还研究了不同阴离子对H64V与N_3^-结合的影响,发现阴离子的存在减弱了N_3^-与H64V之间的结合力.

Mutating the histidine 64 to valine,the gene of Neuroglobin（Ngb） mutant H64V was constructed and its protein was expressed and purified.This mutation changed the coordination geometry of neuroglobin from hexa-to penta-coordinated.The interaction of neuroglobin mutant H64V with azide anion（N_3^-） was investigated by spectroscopy.UV-Vis absorbance spectra showed that the binding of mutant H64V to N_3^- induced the change of the Soret-band absorption peak from 406 nm to 418 nm.Fluorescence spectra indicated that the fluorescence of mutant H64V was quenched by N_3^- through static quenching mechanism.The binding equilibrium dissociation constant and thermodynamic parameters between mutant H64V and N_3^- were calculated.In addition,the effects of different anions on their binding were studied,the results showed that the anions reduced the binding ability between mutant H64V and azide anion.