151. The structure of bacterial ParM filaments
- Author
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Albina Orlova, John E. Heuser, Edward H. Egelman, R. Dyche Mullins, Vitold E. Galkin, and Ethan C. Garner
- Subjects
Models, Molecular ,Cell division ,Escherichia coli Proteins ,Protein subunit ,Cryoelectron Microscopy ,Molecular Sequence Data ,ParM ,DNA replication ,macromolecular substances ,Protein degradation ,Biology ,Actins ,Article ,Cell biology ,Protein filament ,Protein Subunits ,Structural Biology ,Escherichia coli ,Protein folding ,Protein Structure, Quaternary ,Molecular Biology ,Actin - Abstract
Bacterial ParM is a homolog of eukaryotic actin and is involved in moving plasmids so that they segregate properly during cell division. Using cryo-EM and three-dimensional reconstruction, we show that ParM filaments have a different structure from F-actin, with very different subunit-subunit interfaces. These interfaces result in the helical handedness of the ParM filament being opposite to that of F-actin. Like F-actin, ParM filaments have a variable twist, and we show that this involves domain-domain rotations within the ParM subunit. The present results yield new insights into polymorphisms within F-actin, as well as the evolution of polymer families.
- Published
- 2007