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Stabilization of SecA ATPase by the primary cytoplasmic salt of Escherichia coli
Author(s) -
Roussel Guillaume,
Lindner Eric,
White Stephen H.
Publication year - 2019
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.3619
Subject(s) - periplasmic space , escherichia coli , biochemistry , atpase , chemistry , maltose binding protein , secretion , cytoplasm , biophysics , biology , enzyme , fusion protein , gene , recombinant dna
Much is known about the structure, function, and stability of the SecA motor ATPase that powers the secretion of periplasmic proteins across the inner membrane of Escherichia coli . Most studies of SecA are carried out in buffered sodium or potassium chloride salt solutions. However, the principal intracellular salt of E. coli is potassium glutamate (KGlu), which is known to stabilize folded proteins and protein‐nucleic acid complexes. Here we report that KGlu stabilizes SecA, including its dimeric state, and increases its ATPase activity, suggesting that SecA is likely fully folded, stable, and active in vivo at 37°C. Furthermore, KGlu also stabilizes a precursor form of the secreted maltose‐binding protein.