Ralaxation analysis of ligand binding to the myoglobin reconstituted with cobartic heme.
Ralaxation analysis of ligand binding to the myoglobin reconstituted with cobartic heme.
复制标题
配体与用钴血红素重构的肌红蛋白结合的松弛分析。
DOI：
10.1021/ic400078w
复制
发表时间：
2013
影响因子：
4.6
通讯作者：
Kawaguchi AT.
中科院分区：
文献类型：
--
作者：
Neya S;Suzuki M;Hoshino T;Kawaguchi AT.
由氧化的Co(III)亚铁血红素重组的肌红蛋白与CN-、N3-、SCN-、吡啶和咪唑表现出较大的亲和力，与早期的理论相反。与Fe(III)肌红蛋白相比，配体引起的电子光谱变化不明显，这是因为配体结合上没有伴随的自旋态跃迁。松弛动力学分析表明，配体的缔合率很小，解离速率仍然很小。在Co(III)肌红蛋白中发现较大的配基亲和力是由于较小的缔合率和较小的解离率的补偿。这与Fe(III)肌红蛋白的连接情况形成鲜明对比，在那里通常可以观察到大的结合率和小的解离率。根据Co(III)具有额外的负电荷并形成比Fe(III)更强的金属-配位键的性质，提出了Co(III)肌红蛋白具有独特的配体结合行为的理论基础。
Myoglobin reconstituted with oxidized Co(III) deuteroheme was found to exhibit relatively large affinities to CN–, N3–, SCN–, pyridine, and imidazole contrary to the early proposal. The ligand-induced changes in electronic spectra were less obvious than those of Fe(III) myoglobin owing to the absence of accompanied spin-state transition on the ligand binding. The relaxation kinetic analysis revealed that the ligand association rates were small and that the dissociation rates were still much smaller. The relatively large ligand affinities in Co(III) myoglobin were found due to the compensation of small association rates with fairly smaller dissociation rates. This is in marked contrast with the ligation profile in Fe(III) myoglobin where large association rates and small dissociation rates are generally observed. The rationale for the characteristic ligand-binding behavior of Co(III) myoglobin was provided on the basis of the properties of Co(III) which has an additional negative charge and forms stronger metal–ligand bonds than Fe(III).