Membrane Proteins Under High Hydrostatic Pressure Reveal Cooperative and Reversible Rupture of Hydrogen Bonds
Arvi Freiberg Dept. of Biophysics and Plant Physiology
Institute of Physics
University of Tartu
Tartu, Estonia
Abstract:
We report the first clear experimental evidence of cooperative and reversible rupture under high external hydrostatic pressure of multiple hydrogen bonds coordinating native chromophore cofactors to the surrounding protein scaffold in photosynthetic membrane complexes. A detailed knowledge of hydrogen bond properties allows insights into basic biological processes, because the presence and individuality of hydrogen bonds govern not only the structure and dynamics but also the catalytic activity of proteins. We have obtained reliable estimates of the strength of the intra-molecular hydrogen bonds that determine the tertiary structures of integral light harvesting membrane proteins. The present work also demonstrates the validity of high-pressure spectroscopy as an effective tool for analyzing the contributions of hydrogen bonds to the stability and function of membrane proteins, and the usefulness of photosynthetic proteins as model systems for detailed membrane protein stability studies.
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