Department of Experimental Physics, Institute of Physics and Technology, Ural Federal University, Ekaterinburg 620002, Russian Federation.
Department of Biochemistry, Jacobs School of Medicine & Medical Sciences, The State University of New York, Buffalo 14214, USA; Department of Biochemistry, University of Delhi South Campus, New Delhi, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2018 Feb 15;191:547-557. doi: 10.1016/j.saa.2017.10.055. Epub 2017 Oct 25.
A comparative study of tetrameric rabbit hemoglobin and monomeric soybean leghemoglobin a in the oxy- and deoxy-forms was carried out using Fe Mössbauer spectroscopy with a high velocity resolution in order to analyze the heme iron electronic structure and stereochemistry in relation to the Mössbauer hyperfine parameters. The Mössbauer spectra of tetrameric rabbit hemoglobin in both forms were fitted using two quadrupole doublets related to the Fe in ɑ- and β-subunits. In contrast, the Mössbauer spectra of monomeric soybean leghemoglobin a were fitted using: (i) two quadrupole doublets for the oxy-form related to two conformational states of the distal His E7 imidazole ring and different hydrogen bonding of oxygen molecule in the oxy-form and (ii) using three quadrupole doublets for deoxy-form related to three conformational states of the proximal His F8 imidazole ring. Small variations of Mössbauer hyperfine parameters related to small differences in the heme iron electronic structure and stereochemistry in tetrameric rabbit hemoglobin and monomeric soybean leghemoglobin a are discussed.
采用高速分辨率的 Fe Mössbauer 光谱法对四聚体兔血红蛋白和单体大豆根瘤血红蛋白 a 的氧合态和脱氧态进行了比较研究，以分析与 Mössbauer 超精细参数相关的血红素铁电子结构和立体化学。使用与 α-和 β-亚基中的 Fe 相关的两个四极子双峰拟合了两种形式的四聚体兔血红蛋白的 Mössbauer 光谱。相比之下，使用以下方法拟合了单体大豆根瘤血红蛋白 a 的 Mössbauer 光谱：（i）两个氧合形式的四极子双峰与远端 His E7 咪唑环的两种构象态以及氧合形式中氧分子不同的氢键有关，（ii）三个氧合形式的四极子双峰与近端 His F8 咪唑环的三种构象态有关。讨论了与四聚体兔血红蛋白和单体大豆根瘤血红蛋白 a 中血红素铁电子结构和立体化学的微小差异相关的 Mössbauer 超精细参数的微小变化。
