Measuring and Manipulating how Proteins Control their Net Charge: Redox Enzymes, Crowded Enzymes, and Aggregated Proteins.

在化学系生命过程化学项目的支持下，贝勒大学的Bryan F.Shaw教授将研究测量和操纵蛋白质静电性质的新方法。与蛋白质的其他性质不同，净静电电荷(表示为“Z”)通常不会被测量或研究。因此，当电子转移到蛋白质或从蛋白质转移时，蛋白质的净电荷如何变化或变化幅度如何，以及细胞内的分子拥挤如何影响这种变化，目前尚不清楚。这种知识差距可能会限制人们对活细胞如何工作的理解。肖博士的研究小组正在使用毛细管电泳法测量不同蛋白质在蛋白质聚集和电子转移过程中的净电荷变化。Shaw研究团队将评估小分子或突变如何控制或改变蛋白质的静电特性，最终影响催化和蛋白质自组装。在这些研究活动的同时，将开发、测试和实施新的工具，使失明大学生能够获得化学图像和数据。肖博士的研究团队将2D数据和图像转换成“石纸”格式。石板是一种触觉图形，当举着环境光时，它会发出类似视频的分辨率。盲人可以通过触摸(触觉感知)来可视化石板数据，而有视力的人可以使用视力来可视化完全相同的石板数据。这种Lithophane数据格式(LDF)通过允许有视力的科学家和盲人科学家之间的数据共享来促进多样性和包容性。拟议的研究重点是蛋白质的净电荷在质子耦合电子转移(PCET)时的变化幅度，而不是与质子转移不耦合的电子转移。将进行实验，以确定在这些氧化还原过程中，某些金属蛋白中的哪些氨基酸残基会影响净电荷的变化。这项拟议的研究还将测量一种酶(例如，核糖核酸酶)的活性如何受到距离长达8？的拥挤蛋白质邻居的净电荷的影响。研究酶的催化活性如何通过最近的拥挤邻居的净电荷来改变，可能会提高我们对细胞蛋白质定位和功能的理解。这项研究还涉及设计和合成小分子，这些小分子可以静电破坏蛋白质和生物表面之间的库仑相互作用。这项研究在生物化学方面具有潜在的影响，包括酶学、生物无机化学和蛋白质生物物理学，因为它检查了基于蛋白质的电子转移、蛋白质拥挤和自组装以及对催化剂的基本静电效应。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With the support from the Chemistry of Life Processes Program in the Division of Chemistry, Professor Bryan F. Shaw from Baylor University will investigate new ways to measure and manipulate the electrostatic properties of proteins. In contrast to other properties of proteins, the net electrostatic charge (denoted “Z”) is not typically measured or studied. Consequently, it is not known how or by what magnitude the net charge of a protein changes when electrons are transferred to or from a protein and how molecular crowding within a cell may affect this change. This knowledge gap may limit the understanding of how living cells work. Dr. Shaw’s research group is using capillary electrophoresis to measure how the net charges of different proteins change during protein crowding and electron transfer. The Shaw research team will evaluate how the electrostatic properties of proteins may be controlled or altered by small molecules or mutations, to ultimately affect catalysis and protein self-assembly. In parallel with these research activities, new tools will be developed, tested, and implemented, to make chemical imagery and data accessible to college students with blindness. Dr. Shaw’s research team converts 2D data and imagery into “lithophane” format. Lithophanes are tactile graphics that glow with video-like resolution when held up to ambient light. Persons with blindness can visualize the lithophane data by touch (tactile sensing), whereas sighted persons can visualize the exact same lithophane data using eyesight. This Lithophane Data Format (LDF) promotes diversity and inclusion by enabling data sharing between sighted and blind scientists.The proposed research focuses on the magnitude of the change in net charge of a protein upon proton-coupled electron transfer (PCET), as opposed to electron transfer that is not coupled to proton transfer. Experiments will be performed to identify which amino acid residues in certain metalloproteins affect the change in net charge during these redox processes. The proposed research will also measure how the activity of an enzyme (e.g., RNase) is affected by the net charge of a crowded protein neighbor at distances up to 8 Å. Investigating how the catalytic activity of enzymes can be altered by the net charge of its nearest crowded neighbor has the potential to improve our understanding of cellular protein localization and function. The research also involves the design and synthesis of small molecules that electrostatically disrupt coulombic interactions between proteins and biological surfaces. The research has potential impact in biochemistry, including enzymology, bioinorganic chemistry, and protein biophysics because it examines fundamental electrostatic effects upon protein-based electron transfer, protein crowding and self-assembly, and upon catalysis.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.