Protein-Nanocrystal Conjugates Support a Single Filament Polymerization Model in R1 Plasmid Segregation

To ensure inheritance by daughter cells, many low-copy number bacterial plasmids, including the R1 drug-resistance plasmid, encode their own DNA segregation systems. The par operon of plasmid R1 directs construction of a simple spindle structure that converts free energy of polymerization of an acti...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of biological chemistry 2008-10, Vol.283 (42), p.28081-28086
Main Authors: Choi, Charina L., Claridge, Shelley A., Garner, Ethan C., Alivisatos, A. Paul, Mullins, R. Dyche
Format: Article
Language:English
Subjects:
Actins - metabolism
Bacterial Proteins - metabolism
Colloids - chemistry
Crystallization
DNA - chemistry
DNA Topoisomerase IV - metabolism
DNA, Bacterial - metabolism
Escherichia coli Proteins - metabolism
Gold - chemistry
Metal Nanoparticles - chemistry
Microscopy, Electron, Transmission
Models, Biological
Nanoparticles - chemistry
Plasmids - metabolism
Proteins - chemistry
Repressor Proteins - metabolism
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:To ensure inheritance by daughter cells, many low-copy number bacterial plasmids, including the R1 drug-resistance plasmid, encode their own DNA segregation systems. The par operon of plasmid R1 directs construction of a simple spindle structure that converts free energy of polymerization of an actin-like protein, ParM, into work required to move sister plasmids to opposite poles of rod-shaped cells. The structures of individual components have been solved, but little is known about the ultrastructure of the R1 spindle. To determine the number of ParM filaments in a minimal R1 spindle, we used DNA-gold nanocrystal conjugates as mimics of the R1 plasmid. We found that each end of a single polar ParM filament binds to a single ParR/parC-gold complex, consistent with the idea that ParM filaments bind in the hollow core of the ParR/parC ring complex. Our results further suggest that multifilament spindles observed in vivo are associated with clusters of plasmids segregating as a unit.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M803833200