Soldatov A V, Ialovega G E, Smolentsev G Iu, Kovtun A P, Della Longa S
Department of Physics, Rostov State University, B. Sadovaya 105, Rostov-na-Donu, 344006 Russia.
Biofizika. 2001 Jul-Aug;46(4):595-600.
The spin transition of Fe in the active center of a myoglobin molecule, stimulated by a temperature variation, was studied by the theoretical multiple scattering analysis of experimental X-ray absorption data. The spin transition was followed by the movement of the Fe ion out of the plane of the heme without substantial changes in the Fe-N distance. It was shown that the X-ray absorption fine structure above the Fe K-edge is sensitive to both local geometry changes near the Fe ion in the active site of the protein and the spin state of the Fe ion itself. The change in the symmetry of Fe coordination lead to modifications of the spectrum shape in the entire interval up to 40 eV above the main edge. It was found that the spin state effects mostly the rising edge, and at energies above 15 eV becomes negligibly small.
通过对实验X射线吸收数据进行理论多重散射分析，研究了温度变化刺激下肌红蛋白分子活性中心铁的自旋转变。自旋转变之后是铁离子移出血红素平面，而铁-氮距离没有实质性变化。结果表明，铁K边以上的X射线吸收精细结构对蛋白质活性位点中铁离子附近的局部几何变化以及铁离子本身的自旋状态均敏感。铁配位对称性的变化导致主边以上整个40 eV区间内光谱形状的改变。结果发现，自旋状态主要影响上升边，在15 eV以上的能量处其影响变得微不足道。
