PROTEIN DYNAMIC EFFECTS ON BIOLOGICAL ELECTRON TRANSFER

蛋白质对生物电子传递的动态影响

• 批准号: 2625781
• 负责人: ALEXEI A STUCHEBRUKHOV
• 金额: $ 2.26万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-04-01 至 2001-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2625781
• 关键词: analytical chemistry; bioenergetics; biophysics; chemical bond; computer simulation; cytochromes; elasticity; electron transport; extracellular matrix proteins; hydrogen bond; hydrogen ions; intermolecular interaction; mathematical model; protein structure function

DESCRIPTION Tunneling is a quantum mechanical effect. It is only important for small particles such as protons and electrons. Standard transition state theory can be successfully applied to most reactions, except for those which transfer small particles (protons or electrons). In reactions that transfer protons or electrons tunneling can make reaction rates appear faster than would be expected from standard transition state theory. This is because the proton or electron can avoid going over the standard transition state barrier and can instead go beneath it to directly appear on the other side of the barrier. Thi is possible because small particles are strongly affected by the uncertainty principle and there is a nonzero probability that the particle can be found at a position where the potential energy exceeds the particle's total energy. For an electron transfer reaction the wave function describing the position and energy of the electron can reach beyond (or beneath) the higher energy barrier for electron transfer. There is a finite probability that the electron will appear on the other side of the barrier, without ever going over the barrier, because its wave function dictates that there is a finite probability that it can be there. Inelastic tunneling, the main topic of the proposed research for this FIRCA, includes the motion of the matrix (it doesn't make the Condon assumption). For inelastic tunneling there is the possibility that nuclear motions can be coupled with the electron transfer process to facilitate the electron transfer This gives additional energy to the electron, through electron-phonon coupling to help it complete the transfer. Figure 2 on page 21 of the proposal illustrates how the inelastic tunneling model (including effects of nuclear motion) is superior to elastic tunneling model (not including effects of nuclear motion) in describing the rate of long-range electron transfers in Ru-modified cytochromes. In summary, it appears that inelastic tunneling (including effects of nuclear motion) is important for long-range biological electron transfers such as thos in photosynthesis and electron transport in oxidative metabolism.

描述 量子力学是一种量子力学效应。 它只对小 粒子，如质子和电子。 标准过渡态理论 可以成功地应用于大多数反应，除了那些 转移小粒子（质子或电子）。 在反应中， 质子或电子隧穿可以使反应速率看起来比 从标准的过渡态理论中可以看出。 这是因为 质子或电子可以避免越过标准过渡态 障碍，而不是去它下面，直接出现在另一边 的屏障。 这是可能的，因为小颗粒是强烈的。 受测不准原理的影响，存在非零概率 粒子可以在势能 超过了粒子的总能量 对于电子转移反应， 描述电子位置和能量的波函数可以达到 超过（或低于）电子转移的较高能量势垒。 那里 是电子出现在另一边的有限概率 而不会越过势垒，因为它的波函数 它存在的概率是有限的 非弹性隧道效应是本次FIRCA拟议研究的主要主题， 包括矩阵的运动（它不做Condon假设）。 对于非弹性隧穿，核运动有可能 与电子转移过程相结合， 这给了额外的能量给电子，通过 电子-声子耦合来帮助它完成转移。 第页上的图2 该提案的第21段说明了非弹性隧道模型（包括 原子核运动的影响）比弹性隧穿模型（不考虑原子核运动的影响）优越上级 包括核运动的影响）， Ru修饰的细胞色素中的电子转移。 总之，似乎非弹性隧穿（包括 核运动）对于长距离生物电子转移是重要的 例如光合作用中Thos和氧化过程中的电子传递 新陈代谢.