Charge regulation in metalloproteins: from electron transfer to self-assembly.

有了这个奖项，化学部门的生命过程化学项目资助了贝勒大学的Bryan Shaw博士，研究蛋白质的净静电荷Z是如何受到电子转移等生化过程的影响的。大多数天然存在的蛋白质在中性pH值下具有净静电荷，这是蛋白质中带正电荷和带负电荷的化学基团数量的不平衡。这种净电荷可能影响许多涉及蛋白质的化学过程，如电子转移或蛋白质聚集。然而，很少有蛋白质在生理pH值下的电荷Z被测量。缺乏对Z的精确测量可能会模糊对基础生物化学的严格理解；对Z的了解可能会创造机会，用化学方法操纵活细胞内的静电力。肖博士的研究小组正在使用为数不多的工具之一来快速测量Z，以研究蛋白质的净电荷如何受到电子转移、分子拥挤和蛋白质聚集的影响，同时也在设计可以影响活细胞内蛋白质静电特性的小分子。肖博士开发了“口腔模型”，使盲人学生能够使用他们的触觉和味觉来可视化蛋白质的结构和电荷（专利号10043413 B2）。口腔模型是由可食用材料制成的已知蛋白质的一口大小的精确3D复制品。学生们通过将模型放入口中来感知模型的结构，而不是用手指感知模型。本研究项目旨在回答以下科学问题：金属蛋白如何以及为什么在单电子转移过程中调节净电荷？当两种蛋白质在溶液中相互接近形成稳定的或短暂的复合物（或聚集）时，每一种蛋白质的净电荷是否按理论预测的大小影响另一种蛋白质的净电荷？高电荷蛋白质的电场能改变与其相互作用的金属酶的活性吗？这些问题正在通过使用“蛋白质电荷阶梯”和毛细管电泳测量不同条件下折叠蛋白质的净电荷Z来解决。这些新知识被应用于芳基酯分子的设计和化学合成，这些芳基酯分子可以通过赖氨酸酰化选择性地放大蛋白质的净电荷。这些“电荷增强”分子被设计用来使静电控制蛋白质自组装成淀粉样原纤维成为可能。这项研究的结果将加深我们对生物化学中静电力的基本理解，并测试这些力在活细胞内被化学操纵的可能性。该奖项反映了美国国家科学基金会的法定使命，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。

With this award, the Chemistry of Life Processes Program in the Chemistry Division is funding Dr. Bryan Shaw from Baylor University to investigate how the net electrostatic charge of proteins, Z, is affected by biochemical processes such as electron transfer. Most naturally-occurring proteins have a net electrostatic charge at neutral pH, that is an imbalance in the number of positively- and negatively-charged chemical groups of the protein. This net charge may affect many chemical processes involving proteins, such as electron transfer or protein aggregation. However, the charge Z at physiological pH has been measured for very few proteins. The lack of accurate measurements of Z may obscure a rigorous understanding of basic biochemistry; the knowledge of Z may create opportunities to chemically manipulate electrostatic forces inside living cells. Dr. Shaw's research group is using one of the very few tools available to rapidly measure Z to study how the net charge of a proteins is affected by electron transfer, molecular crowding, and protein aggregation and is also designing small molecules that can affect the electrostatic properties of proteins inside living cells. Dr. Shaw develops "mouth models" to enable students who are blind to use their touch and taste to visualize the structure and charge of proteins (Patent No. 10,043,413 B2). The mouth models are bite-sized exact 3D replicas of known proteins made of edible material. Students sense the structure of the model by placing the model in their mouth instead of sensing the model with their fingers.This research project seeks to answer the following scientific questions: how and why do metalloproteins regulate net charge during single electron transfer? When two proteins approach one another in solution to form a stable or transient complex (or to crowd), does the net charge of each protein affect the other's net charge by the magnitude predicted by theory? Can the electric field of a highly-charged protein alter the activity of a metalloenzyme with which it interacts? These questions are being addressed by measuring the net charge Z of folded proteins under various conditions using "protein charge ladders" and capillary electrophoresis. The new knowledge is applied to the design and chemical synthesis of aryl ester molecules that can selectively amplify the net charge of proteins via lysine acylation. These "charge boosting" molecules are designed to make possible electrostatic control the self-assembly of proteins into amyloid-like fibrils. The results of this research will deepen our fundamental understanding of the electrostatic forces in biological chemistry and to test the possibility that these forces can be chemically manipulated inside living cells.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.