TY - JOUR
T1 - In-Cell Titration of Small Solutes Controls Protein Stability and Aggregation
AU - Sukenik, Shahar
AU - Salam, Mohammed
AU - Wang, Yuhan
AU - Gruebele, Martin
N1 - Publisher Copyright:
Copyright © 2018 American Chemical Society.
PY - 2018/8/22
Y1 - 2018/8/22
N2 - The components of the intracellular environment vary widely in size: from large multiprotein complexes to atomic ions. Besides water, low-molecular-weight solutes (<1 kDa) such as electrolytes, metabolites, and carbohydrates are by far the most abundant of these components. Small solutes are thus key contributors to the solvation environment in the cell. Small solutes have been known for decades to alter protein structure or activity in vitro, through their interactions with protein surfaces or hydration shells. Here we use the cell itself as our test tube, by titrating its hydration, ion, or carbohydrate composition systematically. We trigger the selective uptake of specific solutes by exposing cells to hyperosmotic media. We then measure protein structure, stability, unfolding kinetics, and aggregation in these different intracellular environments by using fast relaxation imaging. We compare these results with controls where solutes cannot enter the cell and only hydration is altered. Protein structure, thermal stability, and aggregation onset all depend on the concentration and chemical nature of the solute titrated into the cell. Our work highlights the important contributions of small solutes in defining how proteins interact within the cell and suggests that intracellular variation of the solute composition could be an important regulator of protein function.
AB - The components of the intracellular environment vary widely in size: from large multiprotein complexes to atomic ions. Besides water, low-molecular-weight solutes (<1 kDa) such as electrolytes, metabolites, and carbohydrates are by far the most abundant of these components. Small solutes are thus key contributors to the solvation environment in the cell. Small solutes have been known for decades to alter protein structure or activity in vitro, through their interactions with protein surfaces or hydration shells. Here we use the cell itself as our test tube, by titrating its hydration, ion, or carbohydrate composition systematically. We trigger the selective uptake of specific solutes by exposing cells to hyperosmotic media. We then measure protein structure, stability, unfolding kinetics, and aggregation in these different intracellular environments by using fast relaxation imaging. We compare these results with controls where solutes cannot enter the cell and only hydration is altered. Protein structure, thermal stability, and aggregation onset all depend on the concentration and chemical nature of the solute titrated into the cell. Our work highlights the important contributions of small solutes in defining how proteins interact within the cell and suggests that intracellular variation of the solute composition could be an important regulator of protein function.
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U2 - 10.1021/jacs.8b04809
DO - 10.1021/jacs.8b04809
M3 - Article
C2 - 30044620
AN - SCOPUS:85050778494
SN - 0002-7863
VL - 140
SP - 10497
EP - 10503
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 33
ER -