Moser Christopher C, Farid Tammer A, Chobot Sarah E, Dutton P Leslie
The Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania, 1005, Stellar-Chance Laboratories, 422, Curie Boulevard, Philadelphia, PA 19104-6059, USA.
Biochim Biophys Acta. 2006 Sep-Oct;1757(9-10):1096-109. doi: 10.1016/j.bbabio.2006.04.015. Epub 2006 May 5.
The single, simple concept that natural selection adjusts distances between redox cofactors goes a long way towards encompassing natural electron transfer protein design. Distances are short or long as required to direct or insulate promiscuously tunneling single electrons. Along a chain, distances are usually 14 A or less. Shorter distances are needed to allow climbing of added energetic barriers at paired-electron catalytic centers in which substrate and the required number of cofactors form a compact cluster. When there is a short-circuit danger, distances between shorting centers are relatively long. Distances much longer than 14 A will support only very slow electron tunneling, but could act as high impedance signals useful in regulation. Tunneling simulations of the respiratory complexes provide clear illustrations of this simple engineering.
自然选择调节氧化还原辅因子之间距离这一单一、简单的概念，对于涵盖天然电子传递蛋白设计大有帮助。距离可根据需要缩短或延长，以引导或隔离随意隧穿的单个电子。在一条链上，距离通常为14埃或更小。在成对电子催化中心，需要更短的距离以跨越额外的能垒，在这些中心中，底物和所需数量的辅因子形成紧密簇。当存在短路危险时，短路中心之间的距离相对较长。远超过14埃的距离仅支持非常缓慢的电子隧穿，但可作为调节中有用的高阻抗信号。呼吸复合体的隧穿模拟清晰地说明了这一简单的工程原理。
