Macromolecular crowding in vitro and in cells

蛋白质-蛋白质相互作用调节所有细胞功能，但它们几乎总是在水中研究，而不是在细胞内复杂而拥挤的环境中研究。这个项目的结果将填补一个关键的空白，阻止代谢的完整描述。将定量生物物理学从简单的解决方案转移到拥挤的环境（包括活细胞内部）的目标是一个重大挑战，具有重要的成果。所获得的知识将增加对生物学的基本理解，并为生产和稳定基于蛋白质的试剂提供信息。这项工作还将促进对本科生和研究生进行尖端研究实践的培训。所有这些努力都是建立美国生物经济的关键。该项目的总体目标是获得有关生理相关条件下蛋白质-蛋白质相互作用的广泛适用知识。重点是在体外同源二聚体的相互作用，在大肠杆菌细胞和斑马鱼（Danio rerio）卵母细胞。总体假设是，在生理相关条件下，溶质和蛋白质复合物之间的静电相互作用主导硬核排除体积的效果。更具体地说，预计共溶质和蛋白质复合物之间的静电吸引会降低复合物的稳定性，而静电排斥会增加稳定性。支持的研究还将为建模者和理论家提供精确模拟细胞过程所需的信息。该项目由生物科学理事会分子和细胞生物科学部的分子生物物理学小组支持。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Protein-protein interactions regulate all cellular functions, yet they are almost always studied in water rather than in the complex and crowded environment that exists inside cells. The results of this project will fill a key gap that prevents a complete description of metabolism. The goal of moving quantitative biophysics from simple solutions to crowded environments, including inside living cells, is a major challenge with important outcomes. The knowledge gained will add to both the fundamental understanding of biology and inform efforts to produce and stabilize protein-based reagents. The work will also facilitate the training of undergraduate and graduate students in the practice of cutting-edge research. All these efforts are key to building the US bioeconomy.The overall goal of the project is to gain broadly-applicable knowledge about protein-protein interactions under physiologically-relevant conditions. The focus is on homodimeric interactions in vitro, in Escherichia coli cells and in zebrafish (Danio rerio) oocytes. The overarching hypothesis is that electrostatic interactions between cosolutes and protein complexes dominate the effect of hard-core excluded volume under physiologically-relevant conditions. More specifically, electrostatic attractions between cosolutes and protein complexes are expected to decrease stability of the complexes, whereas electrostatic repulsions are expected to increase stability. The supported research will also deliver to modelers and theoreticians the information required to produce accurate simulations of cellular processes. This project is supported by the Molecular Biophysics Cluster of the Molecular and Cellular Biosciences Division in the Biological Sciences Directorate.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.