Squeezing Out Secrets: How Pressure Reveals Structural Dynamics Across Whole Proteomes

TL;DR

This paper introduces a new method to study how pressure affects protein structures, revealing hidden conformational states and their functional roles.

Contribution

The novel high-pressure limited proteolysis (HiP-LiP) technique enables proteome-wide detection of pressure-sensitive structural changes.

Findings

Pressure-sensitive regions in proteins correlate with active sites and functional dynamics.

HiP-LiP maps reveal new targets for structural studies and potential binding partners.

Highly charged regions are particularly responsive to pressure changes.

Abstract

The effects of hydrostatic pressure on biomolecules are seemingly paradoxical. Rather than simply shrinking in size, biomolecules often reduce their effective volume using conformational changes that expose natural voids to the solvent. Due to hydrogen bond networks, bulk water itself is a very open structure that when disrupted, can collapse, effectively reducing its own volume. This is most evident in the well-known phenomenon of electrostriction, in which highly charged ions effectively compress surrounding layers of bulk water. Thus, both biomolecules and surrounding layers of water and ions can respond to pressure in potentially revealing ways. For this reason, hydrostatic pressure has recently proven a valuable means of populating physiologically important, but normally invisible conformational states (Wang J, et al. (2023) PNAS 120:e2215556120). Until now, we have had no way to tell, in the vast sea of biomolecules, which are pressure sensitive. To better identify such proteins and to help understand their structural behavior and physiological role, we introduce a novel structural technique: high-pressure limited proteolysis (HiP- LiP), a powerful new tool for detecting subtle conformational changes in response to pressure on a proteome-wide scale (Moran HM, et al. (2024) PRX Life 2:033011). By mapping residue-level changes to both experimental and predicted structures, we find that pressure-sensitive regions correlate with active sites and functionally relevant structural dynamics, particularly involving highly charged species. These maps are a rich source of new targets for structural and biophysical studies, possibly revealing unknown binding partners and associated dynamics under both normal and extreme conditions. This talk will discuss the methodology of HiP-LiP, analyze proteome-wide tends, and present multiple structural examples.