Related Experiment Video
Updated: May 12, 2026

Assessment of Dictyostelium discoideum Response to Acute Mechanical Stimulation
Published on: November 9, 2017
SpoIIIE mechanism of directional translocation involves target search coupled to sequence-dependent motor stimulation
Diego I Cattoni1, Osvaldo Chara, Cédric Godefroy
1Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Université de Montpellier I & II, 34090 Montpellier, France.
Abstract:
SpoIIIE/FtsK are membrane-anchored, ATP-fuelled, directional motors responsible for chromosomal segregation in bacteria. Directionality in these motors is governed by interactions between specialized sequence-recognition modules (SpoIIIE-γ/FtsK-γ) and highly skewed chromosomal sequences (SRS/KOPS). Using a new combination of ensemble and single-molecule methods, we dissect the series of steps required for SRS localization and motor activation. First, we demonstrate that SpoIIIE/DNA association kinetics are sequence independent, with binding specificity being uniquely determined by dissociation. Next, we show by single-molecule and modelling methods that hexameric SpoIIIE binds DNA non-specifically and finds SRS by an ATP-independent target search mechanism, with ensuing oligomerization and binding of SpoIIIE-γ to SRS triggering motor stimulation. Finally, we propose a new model that provides an entirely new interpretation of previous observations for the origin of SRS/KOPS-directed translocation by SpoIIIE/FtsK.
Related Concept Videos
Cotranslational Protein Translocation
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
The Movement of Organelles and Vesicles
Mechanism of Ciliary Motion
The cilia are made up of microtubules in a 9+2 arrangement, with nine microtubule doublet ring bundles, surrounding a pair of central singlet microtubule bundles. The doublet microtubule bundles are...
Energy to Drive Translocation
Generally, polypeptides are unfolded by two distinct...
Bacterial Translocation and Protein Secretion
Protein Transport to the Thylakoids
