含二硫键蛋白质折叠和聚集的动力学和物理机制

Disulfide-containing protein is one of the most important components in protein family and plays a vital role in various biological systems. However, due to the extensive involvement of the formation and rupture of disulfide bonds, it is difficult to study the folding of disulfide-containing proteins experimentally. There still lacks a general mechanism for the oxidative folding process. Moreover, due to the lack of an effective potential in describing the formation and rupture of disulfide bonds, theoretical work concerning the folding process of disulfide-containing proeins is also very rare. In this project, we plan to build a theoretical model to describe the formation and rupture of disulfide bonds, which can be used to characterize the realistic oxidative folding processes of several typical disulfide-containing proteins, such as BPTI and hirudin. In addition, we also plan to use a novel method to control the self-assembly of disulfide-containing proteins under physiological condition by using UV illumination. Combining with the simulation results, we try to obtain a physical mechanism of the self-assembling process of disulfide-containing proteins under UV illumination. This will be helpful for the engineering of protein-based drug delivery system suitable for drug delivery and cancer therapy. Our studies on disulfide-containing proteins will be important for the understanding of the physical mechanism of their folding and aggregation, for the synthesis of the novel biomaterials, and for the interpretation of the potential mechanism of these vital diseases induced by protein misfolding and aggregation.

含有二硫键蛋白质是蛋白质家族中一类含量众多的成员，在生物体许多功能的执行中扮演了极其重要的角色。其折叠和聚合过程中由于牵涉到大量的硫键形成和断裂，实验上迄今仍没有一个统一的机制。而理论上由于缺乏一个描述硫键形成和断裂的模型，很少研究涉及含有二硫键的蛋白质。本项目拟构建一个包含二硫键形成和打开的理论模型，运用简化的分子动力学模拟方法，研究BPTI等几个典型含有硫键蛋白质的氧化折叠过程，探索其折叠和聚合过程的动力学和物理机制。同时，本项目还在实验上利用紫外光照办法研究在生理环境中含有二硫键蛋白质自组装聚集的动力学过程，并结合计算机模拟，揭示其自组装的物理机制。另外,根据自组装原理探索具有肿瘤靶向功能的蛋白质载药体系合成，并研究其在肿瘤治疗上的功效。这些研究，对于理解含硫键蛋白质的氧化折叠机制、探究蛋白质自组装聚集、研制新型生物功能材料和理解蛋白质聚集相关疾病的致病机理，均有着十分重要的作用。

在项目资助下，我们根据项目计划安排，构建了可以刻画含二硫键蛋白质氧化折叠过程的分子动力学方法，在国际上首次成功模拟了典型含二硫键蛋白质牛胰核糖核酸酶抑制剂（BPTI）的氧化折叠过程，并结合实验手段研究了含有二硫键蛋白质自组装的物理机制以及其在靶向功能载药纳米粒子体系中的应用，还对蛋白质功能运动的力学调控等和项目相关方面进行了深入的研究，取得了一系列重要的研究结果，项目共发表高水平文章17篇（其中包括第一作者发表的PNAS 1篇，参与完成的Nature Communications 1篇和Angew Chemie Int Ed 1篇），项目在站培养了博士后2人（均已出站），培养了博士生3人，硕士生3名。项目资助下，项目人员多次出国参参加国际会议及和项目相关的相关学术交流，和国外一流专家学者建立了很好的合作关系。总之，我们如期完成了项目的计划任务，实现了预期目标。