一个密度函数理论调查Fe-N-O结合在血红蛋白和模型系统的密度函数理论调查
Yong Zhang1, William Gossman, Eric Oldfield
1Department of Chemistry, 600 South Mathews Avenue, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Journal of the American Chemical Society
|December 25, 2003
概括
密度函数理论准确地计算了Mössbauer光谱学和EPR高精度合常数,用于化化合物. 这使得能够精确地确定金属蛋白中的铁-酸盐键几何结构.
科学领域:
- 计算化学计算化学
- 生物物理学的生物物理.
- 量子力学就是量子力学.
背景情况:
- 亚基复合物在生物系统中至关重要.
- 准确地确定铁-酸盐几何结构对于理解蛋白质功能至关重要.
- 以前的计算方法在预测这些几何形状方面存在局限性.
研究的目的:
- 为了执行密度函数理论 (DFT) 对Mössbauer四极分裂和NO模型化合物中的异构体移位的计算.
- 计算一个模型Fe (II) (NO) (imidazole) 复合体的Mössbauer参数和电子磁共振 (EPR) 超精密合常量.
- 通过采用Z表面方法来确定尼特血红素中最可能的Fe-NO键长和Fe-NO键角.
主要方法:
- 密度函数理论 (DFT) 的计算.
- 莫斯巴乌尔四极分裂和同位素转移计算.
- 电子磁共振 (EPR) 超精密合常数的计算.
- 属性表面和Z-表面计算以确定债券几何概率.
主要成果:
- DFT的计算显示了NO模型的理论和实验Mössbauer数据之间的良好一致.
- 采用Z表面方法的结果是,对于基血红蛋白,Fe-NO键的最可能长度为1.79 Å,Fe-NO键的角度为136°137°.
- 结合复合体的计算几何与蛋白质中发现的几何相一致.
- 在蛋白质中,高度曲的Fe-N-O角度或非常长的Fe-NO键长被发现是能量不利的.
结论:
- 在Mössbauer光谱和EPR超精密合常量可以准确地计算酸胺系统.
- 计算方法允许精确确定金属蛋白中的Fe-N-O几何形状.
- Z-表面方法适用于二磁性 (CO) 和二磁性 (NO) 血红蛋白.
- 蛋白质中的金属-联体结合几何形状与模型系统中观察到的几何形状非常相似.
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