TY - JOUR
T1 - Volume and compressibility differences between protein conformations revealed by high-pressure NMR
AU - Xu, Xingjian
AU - Gagné, Donald
AU - Aramini, James M.
AU - Gardner, Kevin H.
N1 - Funding Information:
We thank Bruce Johnson (CUNY ASRC) for developing new extensions of the NvFX software package (44,45) for pressure NMR analysis and members of the Gardner laboratory for constructive comments. This work was supported by National Science Foundation grant MCB 1818148 (K.H.G.) and Fonds de Recherche Québec – Nature et Technologie fellowship B3X (D.G.).
Funding Information:
This work was supported by National Science Foundation grant MCB 1818148 (K.H.G.) and Fonds de Recherche Québec – Nature et Technologie fellowship B3X (D.G.).
Publisher Copyright:
© 2021 Biophysical Society
PY - 2021/3/2
Y1 - 2021/3/2
N2 - Proteins often interconvert between different conformations in ways critical to their function. Although manipulating such equilibria for biophysical study is often challenging, the application of pressure is a potential route to achieve such control by favoring the population of lower volume states. Here, we use this feature to study the interconversion of ARNT PAS-B Y456T, which undergoes a dramatic +3 slip in the β-strand register as it switches between two stably folded conformations. Using high-pressure biomolecular NMR approaches, we obtained the first, to our knowledge, quantitative data testing two key hypotheses of this process: the slipped conformation is both smaller and less compressible than the wild-type equivalent, and the interconversion proceeds through a chiefly unfolded intermediate state. Data collected in steady-state pressure and time-resolved pressure-jump modes, including observed pressure-dependent changes in the populations of the two conformers and increased rate of interconversion between conformers, support both hypotheses. Our work exemplifies how these approaches, which can be generally applied to protein conformational switches, can provide unique information that is not easily accessible through other techniques.
AB - Proteins often interconvert between different conformations in ways critical to their function. Although manipulating such equilibria for biophysical study is often challenging, the application of pressure is a potential route to achieve such control by favoring the population of lower volume states. Here, we use this feature to study the interconversion of ARNT PAS-B Y456T, which undergoes a dramatic +3 slip in the β-strand register as it switches between two stably folded conformations. Using high-pressure biomolecular NMR approaches, we obtained the first, to our knowledge, quantitative data testing two key hypotheses of this process: the slipped conformation is both smaller and less compressible than the wild-type equivalent, and the interconversion proceeds through a chiefly unfolded intermediate state. Data collected in steady-state pressure and time-resolved pressure-jump modes, including observed pressure-dependent changes in the populations of the two conformers and increased rate of interconversion between conformers, support both hypotheses. Our work exemplifies how these approaches, which can be generally applied to protein conformational switches, can provide unique information that is not easily accessible through other techniques.
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U2 - 10.1016/j.bpj.2020.12.034
DO - 10.1016/j.bpj.2020.12.034
M3 - Article
C2 - 33524371
AN - SCOPUS:85100814012
SN - 0006-3495
VL - 120
SP - 924
EP - 935
JO - Biophysical journal
JF - Biophysical journal
IS - 5
ER -