分子动力学衍生的有色噪声介导微管蛋白中色氨酸激子的安德森局域化和环境辅助传输
Molecular Dynamics-Derived Coloured Noise Mediates Anderson Localisation and Environment-Assisted Transport of Tryptophan Excitons in Tubulin
AI总结：
研究微管蛋白中色氨酸激子传输，通过全原子分子动力学模拟表征耦合蛋白质-溶剂浴涨落，其有色噪声使慢蛋白质模式致安德森局域化，快水模式助量子传输，与白噪声模型不同，该流程可推广至其他色素-蛋白质系统。
AI中文摘要：
微管蛋白αβ-二聚体中的色氨酸残基形成有序芳香网络，被认为即使在生理环境噪声下也能支持量子激子传输。现有研究大多假设白噪声退相，但生理条件下与色氨酸位点耦合的蛋白质-溶剂浴的统计特性仍未明确。本文通过在310K下对溶剂化微管蛋白二聚体进行全原子分子动力学模拟来表征该涨落浴，结合高频和长时间轨迹，采样间隔分别为10fs和10ps。位点能量涨落的自相关是三指数的，有三种分离的衰减模式。慢的蛋白质模式引入强准静态无序导致安德森局域化，而两个快的水模式通过共振频繁调节发色团对，实现环境辅助量子传输。在完整的八位点网络上，有色噪声浴将激子主要限制在强耦合的近端色氨酸对中，与标准白噪声哈肯-施特罗布尔模型预测的更均匀离域形成鲜明对比。我们的工作流程可推广到其他有溶剂暴露发色团的色素-蛋白质系统。
英文摘要：
The tryptophan residues in tubulin $αβ$-dimers form an ordered aromatic network that has been proposed to support quantum exciton transport even under physiological environmental noise. Existing studies of this system mostly assume white-noise dephasing, but the statistical properties of the protein-solvent bath coupled to tryptophan sites remain uncharacterised under physiological conditions. Here we characterise this fluctuation bath via all-atom molecular dynamics simulations of a solvated tubulin dimer at 310 K, combining high-frequency and long-time trajectories with 10 fs and 10 ps sampling intervals. The resulting autocorrelation of the site-energy fluctuations is tri-exponential, with three well-separated decay modes: sub-100-fs and picosecond fluctuations driven by water dynamics, and a nanosecond mode originating from protein conformational rearrangements. All three modes fall deep within the non-Markovian regime. We further demonstrate that the slow protein mode introduces strong quasi-static disorder, which results in Anderson localisation, while the two fast water modes frequently tune chromophore pairs through resonance, enabling environment-assisted quantum transport (ENAQT). On the full eight-site network, the coloured-noise bath confines excitons predominantly to strongly coupled proximal tryptophan pairs, in marked contrast to the more uniform delocalisation predicted by the standard white-noise Haken-Strobl model. Our workflow generalises to other pigment-protein systems with solvent-exposed chromophores.
