Electrostatic effects in hemoglobin: hydrogen ion equilibria in human deoxy- and oxyhemoglobin A.
Electrostatic effects in hemoglobin: hydrogen ion equilibria in human deoxy- and oxyhemoglobin A.
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DOI：
10.1021/bi00577a011
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发表时间：
1979-05
期刊：
影响因子：
2.9
通讯作者：
J. B. Matthew;G. Hanania;F. Gurd
中科院分区：
文献类型：
--
作者：
J. B. Matthew;G. Hanania;F. Gurd
Shire等人的修正的Tanford-Kirkwood理论。[Shire，S.J.，Hanania，G.I.H.，&Gurd，F.R.N.(1974)生物化学13,2967]将静电相互作用应用于人脱氧血红蛋白和氧合血红蛋白的氢离子平衡。氧合血红蛋白的原子坐标是通过对脱氧血红蛋白结构的α和β链应用适当的刚性旋转函数来产生的[Fermi，G.(1975)J.Mol。比奥尔。97,237]。该模型使用了从蛋白质晶体结构、带电氨基酸残基的原子坐标和静态溶剂可及性因子得出的两组参数来反映它们各自在溶剂中的暴露程度。基于一组一致的pKint值的理论滴定曲线与实验电位曲线非常接近。半滴定各蛋白质位置的理论pk值与两个四元状态的可用观测值相对应。结果揭示了四聚体结构中大量静电相互作用的累积效应，以及某些可电离基团的静态溶剂可及性的变化导致的四元转变的主要效应。
The modified Tanford-Kirkwood theory of Shire et al. [Shire, S. J., Hanania, G.I.H., & Gurd, F.R.N. (1974) Biochemistry 13, 2967] for electrostatic interactions was applied to the hydrogen ion equilibria of human deoxyhemoglobin and oxyhemoglobin. Atomic coordinates for oxyhemoglobin were generated by the application of the appropriate rigid rotation function to alpha and beta chains of the deoxyhemoglobin structure [Fermi, G. (1975) J. Mol. Biol. 97, 237]. The model employs two sets of parameters derived from the crystalline protein structures, the atomic coordinates of charged amino acid residues and static solvent accessibility factors to reflect their individual degrees of exposure to solvent. Theoretical titration curves based on a consistent set of pKint values compared closely with experimental potentiometric curves. Theoretical pK values at half-titration for individual protein sites corresponded to available observed values for both quaternary states. The results bring out the cumulative effects of numerous electrostatic interactions in the tetrameric structures and the major effects of the quaternary transition that result from changes in static solvent accessibility of certain ionizable groups.