红螺菌细胞色素c'的穆斯堡尔研究。

Mössbauer studies of cytochrome c' from Rhodospirillum rubrum.

作者信息

Emptage M H, Zimmermann R, Que L, Münck E, Hamilton W D, Orme-Johnson W H

出版信息

Biochim Biophys Acta. 1977 Nov 25;495(1):12-23. doi: 10.1016/0005-2795(77)90235-5.

PMID:199273

Abstract

Cytochrome c' from Rhodospirillum rubrum has been investigated in the ferric form with Mössbauer and EPR spectroscopy. In the pH range from 6 to 9.5, three species are observed which belong to two pH-dependent equilibria with pK values near 6 and 8.5. The pK = 6 transition is resolved only with high-field Mössbauer spectroscopy. For the three species we have determined the zero-field splitting parameters and the hyperfine coupling constants. The data were fitted to a spin Hamiltonian which takes into account a weak mixing of excited S = 3/2 states into the sextet ground manifold. The low temperature spectra clearly show that the quadruple coupling constant deltaEQ is positive for ferricytochrome c' and thus in accord with all other high-spin ferric heme proteins.

摘要

利用穆斯堡尔谱和电子顺磁共振波谱对来自深红红螺菌的细胞色素c'的三价铁形式进行了研究。在pH值为6至9.5的范围内，观察到三种物质，它们属于两个pH依赖性平衡，其pK值接近6和8.5。pK = 6的转变仅通过高场穆斯堡尔谱得以分辨。对于这三种物质，我们测定了零场分裂参数和超精细耦合常数。数据被拟合到一个自旋哈密顿量，该哈密顿量考虑了激发态S = 3/2对六重态基态流形的弱混合。低温光谱清楚地表明，对于三价铁细胞色素c'，四重耦合常数δEQ为正，因此与所有其他高自旋三价铁血红素蛋白一致。