Cell-free study of F plasmid partition provides evidence for cargo transport by a diffusion-ratchet mechanism

Increasingly diverse types of cargo are being found to be segregated and positioned by ParA-type ATPases. Several minimalistic systems described in bacteria are self-organizing and are known to affect the transport of plasmids, protein machineries, and chromosomal loci. One well-studied model is the...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2013-04, Vol.110 (15), p.5751-5751
Main Authors: Vecchiarelli, Anthony G., Hwang, Ling Chin, Mizuuchi, Kiyoshi
Format: Article
Language:English
Subjects:
Actin Cytoskeleton - chemistry
Actins - metabolism
Adenosine triphosphatase
Adenosine Triphosphatases - metabolism
Adenosine Triphosphate - chemistry
Bacteria
Bacteria - metabolism
Bacterial Proteins - metabolism
Biological Sciences
Biological Transport
Cell-Free System - metabolism
Cells
Chromosomes
Chromosomes - ultrastructure
Deoxyribonucleic acid
Diffusion
DNA
DNA - chemistry
Escherichia coli - metabolism
Green Fluorescent Proteins - metabolism
Microfluidics
Microtubules - metabolism
Motion
Plasmids
Plasmids - metabolism
PNAS Plus
PNAS PLUS: SIGNIFICANCE STATEMENTS
Proteins
Surface Properties
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Summary:Increasingly diverse types of cargo are being found to be segregated and positioned by ParA-type ATPases. Several minimalistic systems described in bacteria are self-organizing and are known to affect the transport of plasmids, protein machineries, and chromosomal loci. One well-studied model is the F plasmid partition system, SopABC. In vivo, SopA ATPase forms dynamic patterns on the nucleoid in the presence of the ATPase stimulator, SopB, which binds to the sopC site on the plasmid, demarcating it as the cargo. To understand the relationship between nucleoid patterning and plasmid transport, we established a cell-free system to study plasmid partition reactions in a DNA-carpeted flowcell. We observed depletion zones of the partition ATPase on the DNA carpet surrounding partition complexes. The findings favor a diffusion-ratchet model for plasmid motion whereby partition complexes create an ATPase concentration gradient and then climb up this gradient toward higher concentrations of the ATPase. Here, we report on the dynamic properties of the Sop system on a DNA-carpet substrate, which further support the proposed diffusion-ratchet mechanism.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.1302745110