量子相干对生物电子转移的贡献
Quantum coherent contributions in biological electron transfer
摘要：
许多生物电子转移（ET）反应是由蛋白质中的金属中心介导的。NADH：泛醌氧化还原酶（复合物I）包含7个铁硫（FeS）簇的分子内链，是生物学中最长的金属中心链之一，也是分子内ET物理模型的测试案例。在生物学中，根据Marcus和Hopfield的半经典理论，分子内ET通常被描述为扩散跳跃过程。然而，最近的研究提出了非平凡量子力学效应在某些生物分子过程中发挥作用的可能性。在这里，我们扩展了半经典模型的生物ET纳入半经典和相干的量子现象，使用量子主方程的基础上的Holstein哈密顿量。我们测试我们的模型上的结构定义的链的FeS簇在复杂的I。通过探索广泛的现实参数，我们发现，当沿链的ET的能量分布是相对平坦的，只是一个小的相干贡献可以提供一个强大的和显着的增加ET率（以上的半经典的扩散跳跃率），即使在生理相关的温度。相反地，当在位能量沿链显著变化时，相干贡献可忽略不计。对于复合物I，一种与许多神经肌肉和退行性疾病相关的关键呼吸酶，我们的研究结果表明，对确保分子内ET不会限制催化速率做出了新的贡献。对于新兴的量子生物学领域，我们的模型旨在作为一个基础，阐明生物ET反应中的相干ET的一般作用。
英文摘要：
Many biological electron transfer (ET) reactions are mediated by metal centres in proteins. NADH:ubiquinone oxidoreductase (complex I) contains an intramolecular chain of seven iron-sulphur (FeS) clusters, one of the longest chains of metal centres in biology and a test case for physical models of intramolecular ET. In biology, intramolecular ET is commonly described as a diffusive hopping process, according to the semi-classical theories of Marcus and Hopfield. However, recent studies have raised the possibility that non-trivial quantum mechanical effects play a functioning role in certain biomolecular processes. Here, we extend the semi-classical model for biological ET to incorporate both semi-classical and coherent quantum phenomena using a quantum master equation based on the Holstein Hamiltonian. We test our model on the structurally-defined chain of FeS clusters in complex I. By exploring a wide range of realistic parameters we find that, when the energy profile for ET along the chain is relatively flat, just a small coherent contribution can provide a robust and significant increase in ET rate (above the semi-classical diffusive-hopping rate), even at physiologically-relevant temperatures. Conversely, when the on-site energies vary significantly along the chain the coherent contribution is negligible. For complex I, a crucial respiratory enzyme that is linked to many neuromuscular and degenerative diseases, our results suggest a new contribution towards ensuring that intramolecular ET does not limit the rate of catalysis. For the emerging field of quantum biology, our model is intended as a basis for elucidating the general role of coherent ET in biological ET reactions.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
