(19) F NMR spectroscopy as a probe of cytoplasmic viscosity and weak protein interactions in living cells.
Protein mobility in living cells is vital for cell function. Both cytosolic viscosity and weak protein-protein interactions affect mobility, but examining viscosity and weak interaction effects is challenging. Herein, we demonstrate the use of (19) F NMR spectroscopy to measure cytoplasmic viscosity and to characterize nonspecific protein-protein interactions in living Escherichia coli cells. The origins of resonance broadening in Escherichia coli cells were also investigated. We found that sample inhomogeneity has a negligible effect on resonance broadening, the cytoplasmic viscosity is only about 2-3 times that of water, and ubiquitous transient weak protein-protein interactions in the cytosol play a significant role in governing the detection of proteins by using in-cell NMR spectroscopy.
Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071 (P.R. China), Fax: (+86) 27-87199291; Graduate University of Chinese Academy of Sciences, Beijing, 100029 (P.R. China).
Yansheng
Y
Ye
Xiaoli
X
Liu
Zeting
Z
Zhang
Qiong
Q
Wu
Bin
B
Jiang
Ling
L
Jiang
Xu
X
Zhang
Maili
M
Liu
Gary J
GJ
Pielak
Conggang
C
Li
D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism; D005462:Fluorine Radioisotopes / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular; D054730:Protein Interaction Domains and Motifs; D025801:Ubiquitin / Q000737:chemistry / Q000378:metabolism; D014783:Viscosity
D029968:Escherichia coli Proteins; D005462:Fluorine Radioisotopes; D025801:Ubiquitin
NMR spectroscopy; cytoplasmic viscosity; fluorine; transient weak interactions