Cowan J A, Upmacis R K, Beratan D N, Onuchic J N, Gray H B
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125.
Ann N Y Acad Sci. 1988;550:68-84. doi: 10.1111/j.1749-6632.1988.tb35324.x.
The distance and driving-force dependences of electron transfer (ET) in a set of four surface-ruthenated myoglobins, in which the heme prosthetic group has been systematically replaced by a series of metalloporphyrins of differing excited-state redox potentials, have provided information on the magnitude [Hab(12.7 A) approximately 6.3 x 10(-3) cm-1] and decay [beta approximately 0.8 A-1, where kET alpha exp [-beta(d - do)]] of protein-mediated donor-acceptor electronic coupling. A reorganization energy lambda approximately 1.3 eV, due to coordination and solvation changes both at and between the ET sites, has been estimated using a rate expression that allows electron-vibration coupling to classical and quantum mechanical modes. The contribution to lambda from the porphyrin and peptide matrix is approximately 0.7 eV. Specific electron-tunneling pathways in the protein have been evaluated.
在一组四个表面钌化肌红蛋白中，电子转移（ET）的距离和驱动力依赖性研究提供了有关蛋白质介导的供体 - 受体电子耦合强度[Hab(12.7 Å) 约为6.3 x 10⁻³ cm⁻¹]和衰减[β约为0.8 Å⁻¹，其中kET ∝ exp [-β(d - do)]]的信息。在这些肌红蛋白中，血红素辅基已被一系列具有不同激发态氧化还原电位的金属卟啉系统地取代。由于电子转移位点处及其之间的配位和溶剂化变化，使用允许电子 - 振动耦合到经典和量子力学模式的速率表达式估计了重组能λ约为1.3 eV。卟啉和肽基质对λ的贡献约为0.7 eV。已评估了蛋白质中特定的电子隧穿途径。
