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Updated: Aug 20, 2026

Förster Resonance Energy Transfer Mapping: A New Methodology to Elucidate Global Structural Features
Published on: March 16, 2022
Structure and function of SecA, the preprotein translocase nanomotor
Eleftheria Vrontou1, Anastassios Economou
1Laboratory Unicellular, Organisms Group, Institute of Molecular Biology and Biotechnology, FO.R.T.H. and Department of Biology, University of Crete, Vassilika Vouton, P.O. Box 1527, GR-711 10 Iraklio, Crete, Greece.
Abstract:
Most secretory proteins that are destined for the periplasm or the outer membrane are exported through the bacterial plasma membrane by the Sec translocase. Translocase is a complex nanomachine that moves processively along its aminoacyl polymeric substrates effectively pumping them to the periplasmic space. The salient features of this process are: (a) a membrane-embedded "clamp" formed by the trimeric SecYEG protein, (b) a "motor" provided by the dimeric SecA ATPase, (c) regulatory subunits that optimize catalysis and (d) both chemical and electrochemical metabolic energy. Significant recent strides have allowed structural, biochemical and biophysical dissection of the export reaction. A model incorporating stepwise strokes of the translocase nanomachine at work is discussed.
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