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用电子转移的半经典模型和量子化学半经验方法对色氨酸-酪氨酸二肽体系进行电子转移动力学参数计算.用AM1方法分别优化给体、受体和桥体的几何构型,用线性反应坐标构造了给体和受体分子间电子转移的双势阱,得到两透热势能面交叉处的反应坐标为R≈0.10,并确定了反应的内重组能及反应热.对色氨酰酪氨酸和酪氨酰色氨酸体系进行闭壳层HF自洽场计算,按Koopmans定理计算体系分子轨道分裂能值△,在R约为O处发现了△的极小值,从而获得色氨酰酪氨酸及酪氨酰色氨酸体系分子内电子转移的电子转移矩阵元V_(DA)分别为0.96kJ·mol~(-1)和0.87kJ·mol~(-1).采用Marcus双球模型估算反应的溶剂重组能为64.60kJ·mol~(-1).
The electron transfer kinetic parameters of the tryptophan-tyrosine dipeptide system were calculated using the semiclassical model of electron transfer and the semicircle method of quantum chemistry. The geometries of donor, acceptor and pontic were optimized by AM1 method. The double-well of electron transfer between donor and acceptor molecule was constructed by linear reaction coordinate, and the reaction coordinate at the intersection of two diathermal potential energy surfaces was R≈0.10, and the internal recombination energy and heat of reaction were determined. Tyrosine and tyrosyl tryptophan closed shell HF self-consistent field calculation, according to the Koopmans theorem to calculate the molecular orbital split energy △, in the R about O minimum △ found, thus The electron transfer matrix elements V DA with intramolecular transfer of tryptophan and tyrosyltryptophan were 0.96 kJ · mol -1 and 0.87 kJ · mol -1, respectively. Solvent recombination energy estimated by Marcus double sphere model was 64.60 kJ · mol ~ (-1).