Quantum Dynamics of Radical Pairs Reactions in Membranes: Elucidating Magnetic Field Effects in Lipid Autoxidation

膜中自由基对反应的量子动力学：阐明脂质自氧化中的磁场效应

基本信息

批准号：
EP/R021058/1
负责人：
Daniel Kattnig
金额：
$ 12.88万
依托单位：
UNIVERSITY OF EXETER
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2018
资助国家：
英国
起止时间：
2018 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FR021058%2F1
关键词：
Quantum Dynamics Radical Pairs Reactions

项目摘要

Radicals are ubiquitous short-lived reaction intermediates that contain a single unpaired electron and are usually created in pairs in a well-defined electronic spin state, either singlet ("anti-parallel spins") or triplet ("parallel spins"). For chemical reactions involving such pairs of radicals, quantum effects can induce a remarkable sensitivity to the intensity and/or orientation of external static magnetic fields as weak as the Earth's magnetic field. The underlying mechanism, the so-called Radical Pair Mechanism, has attracted widespread interest from the scientific community and general audiences owing to its putative relevance to animal magnetoreception and possibly adverse effects of weak electromagnetic fields on human health. Indeed, a multitude of studies have suggested an association between weak magnetic field exposure and increased levels of oxidative stress, genotoxic effects and apoptosis/necrosis. While detailed interaction models are still lacking - a factor that severely impedes the assessment of partly controversial literature on this subject and the advancement of guidelines for magnetic field exposure - the oxidative degradation of phospholipids appears as an overarching motif in many exposure studies. Indeed, reactive oxygen species and the free radicals they induce are known to attack polyunsaturated fatty acids in phospholipid membranes, thereby initiating lipid peroxidation reactions, which alter membrane characteristics and induce cell damage. Through termination and degenerate chain branching steps of this free-radical chain reaction, magnetosensitivity is feasibly imparted. Unfortunately, mechanistic details and a sound theoretical understanding of these effects are still lacking: the Radical Pair Mechanism has not yet been developed for systems confined to two dimensions, such as lipid bilayers, and the properties of the involved radicals have not been characterized with respect to magnetosensitive pathways and spin relaxation.Here, I propose a theoretical and computational investigation of intricacies of the radical pair mechanism at two-dimensional interfaces and the exploration of related amplification mechanisms beyond the standard Radical Pair Mechanism that I have recently suggested in the field of magnetoreception, but which are utterly unexplored in this context. In particular, I will focus on:a) the effect of confining the diffusion of coupled radical pairs to two dimensions,b) the potential for molecular motion to result in noise-enhanced magnetic field effects (MFEs), andc) the so-called chemical Zeno effect, by which MFEs are amplified by scavenging reactions with spin-carrying reaction partners.I envisage to find support for the hypothesis that unexpectedly large MFEs could ensue in these confined systems, intrinsically and as a consequence of the abovementioned secondary amplification effects. In addition to providing a better, more complete understanding of MFEs, our work will also reveal how subtle quantum effects can be sustained and amplified in noisy environments. These insights are essential to the emerging field of Quantum Biology and could pave the way to enhanced quantum devices and sensors with improved resilience to environmental noise. Furthermore, if such amplification schemes are found to apply to biologically relevant reactions, it could prompt a reassessment of the health risks of weak magnetic field exposure and future research into the use of MFEs as therapeutics to boost the immune response via the radical pair mechanism.Abbreviations: MFE = Magnetic Field Effect; RPM = Radical Pair Mechanism.

自由基是无处不在的短寿命反应中间体，其中包含单个未配对的电子，通常以明确定义的电子自旋状态成对创建，无论是单旋（“反平行旋转”）或三重态（“平行旋转”）。对于涉及此类自由基对的化学反应，量子效应可以引起对像地球磁场一样弱的外部静态磁场强度和/或方向的显着敏感性。所谓的激进对机制的基本机制引起了科学界和一般受众的广泛兴趣，这是由于其与动物磁受伤的假定相关，并且可能对弱电磁场对人类健康的不利影响。实际上，许多研究表明，弱磁场暴露与氧化应激水平增加之间存在关联，遗传毒性作用和凋亡/坏死。尽管仍然缺乏详细的相互作用模型 - 这是一个严重阻碍对该主题的部分有争议的文献评估的因素，并提高了磁场暴露指南的发展 - 在许多暴露研究中，磷脂的氧化降解似乎是一个超大的基础。实际上，已知活性氧和它们诱导的自由基在磷脂膜中攻击多不饱和脂肪酸，从而启动脂质过氧化反应，从而改变膜特性并诱导细胞损伤。通过这种自由基链反应的终止和退化的链分支步骤，磁敏感是可行的。不幸的是，机械细节和对这些效果的合理理论理解仍然缺乏：尚未开发出限制在两个维度（例如脂质双层）的系统（例如脂质双层）的系统，以及所涉及的自由基的特性尚未在磁性敏感的途径和旋转方面表征。我最近在磁体受体领域提出的标准激进对机制的相关放大机制的探索，但在这种情况下却完全没有探索。 In particular, I will focus on:a) the effect of confining the diffusion of coupled radical pairs to two dimensions,b) the potential for molecular motion to result in noise-enhanced magnetic field effects (MFEs), andc) the so-called chemical Zeno effect, by which MFEs are amplified by scavenging reactions with spin-carrying reaction partners.I envisage to find support for the hypothesis that unexpectedly large由于上述次级扩增效应，可能会在这些密闭系统中发生MFE。除了提供对MFE的更好，更完整的了解外，我们的工作还将揭示如何在嘈杂的环境中持续和放大微妙的量子效应。这些见解对于量子生物学的新兴领域至关重要，可以为增强量子设备和传感器铺平道路，并提高对环境噪声的弹性。此外，如果发现这种扩增方案适用于生物学相关的反应，则可以重新评估磁场暴露弱的健康风险和未来对使用MFE作为治疗剂的研究，以通过自由度成对来增强免疫反应，以增强免疫反应。 rpm =激进对机理。