Ikeda-Saito M, Inubushi T, McDonald G G, Yonetani T
J Biol Chem. 1978 Oct 25;253(20):7134-7.
The paramagnetically shiftedd proton nuclear magnetic resonance spectra of iron-cobalt hybrid hemoglobins [alpha(Co)2beta(Fe)2 and alpha(Fe)2beta(Co)2], as well as those of deoxy forms of cobalt hemoglobin, iron hemoglobin, and their isolated chains, have been measured at 360 MHz. The proton NMR signals of the deoxy forms of iron and cobalt hemoglobins were individually assigned to each subunit. The NMR spectral characteristics of the alpha subunits in deoxycobalt hemoglobin, as well as those in deoxy-alpha(Co)2beta(Fe)2, were found to be quite different from those of beta(Co)2 subunits or isolated alpha-SH chain. Upon ligation of carbon monoxide to the beta(Fe)2 subunits in alpha(Co)2beta(Fe)2, the spectral properties of deoxy-alpha(Co)2 subunits became similar to those of the deoxy-beta(Co)2 subunits. No significant change in the NMR spectrum of the beta(Co)2 subunits was observed in alpha(Fe)2beta(Co)2 upon ligation of carbon monoxide to the alpha(Fe)2 subunits. These observations show the linkage of the electronic structure of the prosthetic groups with the subunits cooperativity in hemoglobin, as well as the inequivalence of the subunits. This is the first report on the paramagnetically shifte proton NMR spectra of the cobalt-substituted hemoproteins.
在360兆赫下测量了铁 - 钴杂合血红蛋白[α(Co)₂β(Fe)₂和α(Fe)₂β(Co)₂]以及钴血红蛋白、铁血红蛋白及其分离链的脱氧形式的顺磁位移质子核磁共振谱。铁血红蛋白和钴血红蛋白脱氧形式的质子核磁共振信号已分别归属到每个亚基。发现脱氧钴血红蛋白中α亚基以及脱氧α(Co)₂β(Fe)₂中α亚基的核磁共振光谱特征与β(Co)₂亚基或分离的α - SH链的特征有很大不同。当一氧化碳与α(Co)₂β(Fe)₂中的β(Fe)₂亚基结合时，脱氧α(Co)₂亚基的光谱性质变得与脱氧β(Co)₂亚基的相似。当一氧化碳与α(Fe)₂β(Co)₂中的α(Fe)₂亚基结合时，未观察到β(Co)₂亚基的核磁共振谱有明显变化。这些观察结果表明了辅基的电子结构与血红蛋白中亚基协同性之间的联系，以及亚基的不等价性。这是关于钴取代血红蛋白质的顺磁位移质子核磁共振谱的首次报道。
