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Updated: Jun 28, 2026

Förster Resonance Energy Transfer Mapping: A New Methodology to Elucidate Global Structural Features
Published on: March 16, 2022
Maximal efficiency of coupling between ATP hydrolysis and translocation of polypeptides mediated by SecB requires two
Chunfeng Mao1, Simon J S Hardy, Linda L Randall
1Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, USA.
Abstract:
SecA is the ATPase that provides energy for translocation of precursor polypeptides through the SecYEG translocon in Escherichia coli during protein export. We showed previously that when SecA receives the precursor from SecB, the ternary complex is fully active only when two protomers of SecA are bound. Here we used variants of SecA and of SecB that populate complexes containing two protomers of SecA to different degrees to examine both the hydrolysis of ATP and the translocation of polypeptides. We conclude that the low activity of the complexes with only one protomer is the result of a low efficiency of coupling between ATP hydrolysis and translocation.
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