Enabling ion Mobility Spectrometry/Mass Spectrometry Methods to Study Conformational Dynamics of Protein Systems

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Christian Bleiholder and his research group at Florida State University are developing new approaches to characterize the structural dynamics of proteins that play critical roles in chemical reactions occurring within biological cells. These new approaches will combine and enhance the capabilities of tandem-ion mobility spectrometry coupled with mass spectrometry in conjunction with computational chemistry methods. Because these approaches can provide new knowledge on the chemistry associated with both normal and abnormal cell biology, they may offer novel insight into the functioning of cells and cell dysfunction, potentially a relevant new tool to provide insight into the evolution of disease. Impact will be enhanced through interactions with academic and industrial collaborators, and by broad dissemination of ideas and results (including software tools) to potential users through websites and workshops. Students working on the project will be trained in instrumentation, computational methods, biochemistry, and analysis of complex data. The dynamic nature of proteins contributes greatly to the chemical reactions of proteins. However, protein motions are challenging to study in the context of complex samples or heterogenous protein systems. Ion mobility spectrometry methods coupled with mass spectrometry (IMS/MS) are well-suited to handle the complexity arising from presence of proteoforms and enable systematic measurements of proteomes, but suffer from two major shortcomings: (1) It remains unclear which aspects of the solution phase protein motions are retained in the absence of solvent; and (2) it is challenging to unambiguously interpret IMS/MS spectra in terms of protein structures from their measured orientationally-averaged collision cross sections. Dr. Bleiholder and his team will characterize which aspects of solution phase motions of liganded and unliganded protein systems are retained in the absence of solvent. This objective is to be accomplished by means of the experimental tandem-trapped IMS/MS (tandem-TIMS/MS) and the computational Structure Relaxation Approximation (SRA) methods recently developed in the Bleiholder laboratory. 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.