Description:

Abstract:  All proteins dynamically sample diverse folded, unfolded, and excited states with differing free energies. Although energy landscapes have been studied for decades, existing methods have been restricted to assaying one protein per sample, limiting the development of quantitative, global models of protein energy landscapes. We developed a new experimental approach to rapidly characterize hundreds to thousands of protein energy landscapes simultaneously by hydrogen exchange mass spectrometry. In this approach, the target protein library is expressed as a mixture from custom-synthesized DNA oligos, and individual intact proteins are resolved by LC-IMS-MS to measure the overall exchange at each timepoint. We applied this approach to examine the energy landscapes of over 1,000 de novo designed miniproteins (43 residues in length) and found wide variation in landscapes, even among designs with similar topologies. The size of our dataset enabled us to statistically analyze the structural origins of the varied landscapes, revealing how different interaction types modulate both stability and conformational fluctuations. Combining these new large-scale experiments with computational modeling should ultimately lead to a quantitative understanding of the structural determinants of protein energy landscapes.

Gabriel Rocklin, PhD
Assistant Professor, Pharmacology
Northwestern University, Feinberg School of Medicine