Dynamic Instability in a DNA-Segregating Prokaryotic Actin Homolog

• DOI: 10.1126/science.1101313
• Publication Date: 2004-11-04T22:23:52Z
• Authors: Ethan C. Garner; Christopher S. Ca...; R. Dyche Mullins
• Keywords: DNA, Bacterial; Kinetics; 0303 health sciences; 03 medical and health sciences; Adenosine Triphosphate; Biopolymers; Bacterial Proteins; Microscopy, Fluorescence; Mutagenesis; Hydrolysis; Fluorescence Resonance Energy Transfer; Actins

Dynamic instability-the switching of a two-state polymer between phases steady elongation and rapid shortening-is essential to the cellular function eukaryotic microtubules, especially during chromosome segregation. Since discovery dynamic instability 20 years ago, no other biological has been found exhibit this behavior. Using total internal reflection fluorescence microscopy resonance energy transfer, we observe that prokaryotic actin homolog ParM, whose assembly is required for segregation large, low-copy number plasmids, displays both symmetrical, bidirectional polymerization. The ParM regulated by adenosine triphosphate (ATP) hydrolysis, filaments are stabilized cap ATP-bound monomers. not related tubulin, so its must have arisen convergent evolution driven set common constraints on polymer-based DNA.