Collaborative Research - Materials World Network: Protein Phase Behavior - Experiments and Simulations

技术摘要：这个由英国布兰迪斯大学、特拉华大学和剑桥大学教职员工参与的合作材料世界网络项目的目标是将蛋白质的分子结构与它们的相互作用能量和相行为联系起来。研究团队将对纯化的蛋白质进行综合实验，并基于现实的模型表示进行模拟，以便进行直接比较。他们将构建两类蛋白质的分子模型，一类基于原子结构信息用于与实验进行定量比较，另一类以此类信息为指导，但提供了一个最小模型来阐明蛋白质溶液的平衡相图和相分离动力学的一般性质。能量和自由能景观将被模拟，相互比较，并通过相行为和渗透第二维里系数的测量进行比较。成核速率的测量和模拟将在经典成核模型的背景下解释，而对单个亚临界核生长的测量和模拟将检验该模型的假设。动力学阻滞态，如非平衡凝胶和沉淀物，将通过实验和模拟来研究。蛋白质溶液的时间处理方案将在模拟和实验中开发，以绕过介于液体和晶体之间的停滞状态。非技术摘要：在生物学中，由于生物环境的复杂性，哪些分子特性导致某些蛋白质结合，哪些阻止相同的蛋白质在集中的细胞内环境中聚集，这一问题在很大程度上仍然没有答案。从生物材料自组装的角度来看，蛋白质-蛋白质相互作用与相行为之间的关系是根本的。如果材料界要将蛋白质用于工程应用，这个问题必须直接面对。这个合作的材料世界网络项目的目标是将蛋白质的分子结构与它们的相互作用能量和相行为联系起来。更广泛的影响将是提高结构生物学中蛋白质结晶的成功率，控制药物应用中的蛋白质聚集，并开发用于药物输送的新型蛋白质凝聚相，这是具有重大科学和工业意义的问题。该项目得到生物材料计划和材料研究部特殊计划办公室的支持。

TECHNICAL SUMMARY:The goal of this collaborative Materials World Network project involving faculty at Brandeis University, the University of Delaware, and the University of Cambridge in the United Kingdom is to relate the molecular structure of proteins to their interaction energies and phase behavior. The research teams will undertake an integrated program of experiment on purified proteins and simulations based on realistic model representations that will allow direct comparisons. They will construct two classes of molecular models of proteins, one based on atomistic structural information for quantitative comparison with experiment and the other guided by such information but providing a minimal model to elucidate generic properties of the equilibrium phase diagrams and phase separation kinetics of protein solutions. The energy and free energy landscapes will be simulated, compared with each other and with measurements of phase behavior and of osmotic second virial coefficients. Measurements and simulations of nucleation rates will be interpreted in the context of the classical nucleation model, while measurements and simulations of the growth of individual precritical nuclei will test the assumptions of that model. Kinetically arrested states, such as non-equilibrium gels and precipitates, will be studied by experiment and simulation. Protocols for the temporal processing of protein solutions will be developed in simulations and experiment in order to navigate around the arrested states that intervene between the liquid and crystal phases.NON-TECHNICAL SUMMARY:In biology, the question of which molecular properties lead some proteins to associate and which prevent the same proteins from aggregating in the concentrated intracellular environment remains largely unanswered because of the complexity of the biological milieu. From the perspective of self-assembly of biomaterials, the relationship between protein-protein interactions and phase behavior is fundamental. If the materials community is going to engineer proteins for applications, this problem must be directly confronted. The goal of this collaborative Materials World Network project is to relate the molecular structure of proteins to their interaction energies and phase behavior. The broader impact will be to improve the success rate of protein crystallization for structural biology, to control protein aggregation for pharmaceutical applications and to develop novel condensed phases of proteins for applications of drug delivery, problems of significant scientific and industrial importance.This project is supported by the Biomaterials program and the Office of Special Programs, Division of Materials Research.