Dried Protein Structure Revealed at the Residue Level by Liquid-Observed Vapor Exchange NMR

Biochemistry. 2021 Jan 19;60(2):152-159. doi: 10.1021/acs.biochem.0c00863. Epub 2021 Jan 5.

Abstract

Water is key to protein structure and stability, yet the relationship between protein-water interactions and structure is poorly understood, in part because there are few techniques that permit the study of dehydrated protein structure at high resolution. Here, we describe liquid-observed vapor exchange (LOVE) NMR, a solution NMR-based method that provides residue-level information about the structure of dehydrated proteins. Using the model protein GB1, we show that LOVE NMR measurements reflect the fraction of the dried protein population trapped in a conformation where a given residue is protected from exchange with D2O vapor. Comparisons to solution hydrogen-deuterium exchange data affirm that the dried protein structure is strongly influenced by local solution stability and that the mechanism of dehydration protection exerted by the widely used protectant trehalose differs from its mechanism of stabilization in solution. Our results highlight the need for refined models of cosolute-mediated dehydration protection and demonstrate the ability of LOVE NMR to inform such models.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acids / chemistry*
  • Bacterial Proteins / chemistry*
  • Deuterium / chemistry*
  • Deuterium Exchange Measurement
  • Freeze Drying
  • Hydrogen / chemistry*
  • Magnetic Resonance Spectroscopy / methods*
  • Protein Conformation
  • Streptococcaceae / metabolism*

Substances

  • Amino Acids
  • Bacterial Proteins
  • IgG Fc-binding protein, Streptococcus
  • Hydrogen
  • Deuterium