Understanding and Manipulating Electrostatic Fields at the Protein鈥揚rotein Interface Using Vibrational Spectroscopy and Continuum Electrostatics Calculations

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• 作者：Andrew W. Ritchie ; Lauren J. Webb
• 刊名：Journal of Physical Chemistry B
• 出版年：2015
• 出版时间：November 5, 2015
• 年：2015
• 卷：119
• 期：44
• 页码：13945-13957
• 全文大小：691K
• ISSN：1520-5207

文摘

Biological function emerges in large part from the interactions of biomacromolecules in the complex and dynamic environment of the living cell. For this reason, macromolecular interactions in biological systems are now a major focus of interest throughout the biochemical and biophysical communities. The affinity and specificity of macromolecular interactions are the result of both structural and electrostatic factors. Significant advances have been made in characterizing structural features of stable protein鈥損rotein interfaces through the techniques of modern structural biology, but much less is understood about how electrostatic factors promote and stabilize specific functional macromolecular interactions over all possible choices presented to a given molecule in a crowded environment. In this Feature Article, we describe how vibrational Stark effect (VSE) spectroscopy is being applied to measure electrostatic fields at protein鈥損rotein interfaces, focusing on measurements of guanosine triphosphate (GTP)-binding proteins of the Ras superfamily binding with structurally related but functionally distinct downstream effector proteins. In VSE spectroscopy, spectral shifts of a probe oscillator鈥檚 energy are related directly to that probe鈥檚 local electrostatic environment. By performing this experiment repeatedly throughout a protein鈥損rotein interface, an experimental map of measured electrostatic fields generated at that interface is determined. These data can be used to rationalize selective binding of similarly structured proteins in both in vitro and in vivo environments. Furthermore, these data can be used to compare to computational predictions of electrostatic fields to explore the level of simulation detail that is necessary to accurately predict our experimental findings.