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Stochastic theory of barrier-crossing processes under large thermal fluctuations

大热波动下越障过程的随机理论

基本信息

批准号：
1778174
负责人：
金额：
--
依托单位：
University of Cambridge
依托单位国家：
英国
项目类别：
Studentship
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=studentship-1778174
关键词：
Stochastic theory barrier crossing processes

项目摘要

Formation of bonds in thermally agitated environments is ubiquitous in biological, solid state, and nuclear physics with many engineering applications. Particles or molecular associations form binary complexes when there is an energy gain upon forming a bond. Examples include nanoparticle absorption to membranes, protein-ligand bindings, and atomic force microscopy (AFM) studies of the cellular membrane. The energy gain upon forming the bond, i.e. the binding energy Q, also determines the bond's stability in an environment with thermal fluctuations. When the binding energy is small compared to thermal fluctuations that have energies of the order kBT, i.e. when Q= kBT ~ 1, the bond is unstable and can break on a short time scale. Conversely, for large binding energies, Q >> kBT, the bond is stable, and the dissociation time is very long. Current theories are successful in the latter case of large binding energy, but fail completely in the opposite limit of low energy/large thermal fluctuations. The goal of this PhD is to fill this gap in our understanding of thermally-activated dissociation processes. Stochastic methods will be employed and combined creatively with Zwanzig-Caldeira-Leggett system-bath Hamiltonian methods to properly describe the role of friction. The theory will be applied to selected important problems such as biomolecular receptor-ligand binding, biological filament dissociation, and alike.

在热搅动环境中形成键在生物、固态和核物理中是普遍存在的，具有许多工程应用。当形成键时有能量增益时，粒子或分子缔合物形成二元复合物。例子包括纳米颗粒吸收到膜，蛋白质-配体结合，和原子力显微镜（AFM）研究的细胞膜。在形成键时的能量增益，即结合能Q，也决定了键在具有热波动的环境中的稳定性。当结合能与具有kBT量级能量的热涨落相比很小时，即当Q= kBT ~ 1时，键是不稳定的，并且可以在短时间尺度上断裂。相反，对于大的结合能，Q >> kBT，键是稳定的，并且解离时间非常长。目前的理论在后一种情况下是成功的大结合能，但完全失败的相反限制的低能量/大的热波动。这个博士学位的目标是填补我们对热活化解离过程的理解中的这一空白。随机方法将被采用，并创造性地与Zwanzig-Caldeira-Leggett系统浴哈密顿方法相结合，以适当地描述摩擦的作用。该理论将应用于选定的重要问题，例如生物分子受体-配体结合、生物丝解离等。