title: The structure of bacterial ParM filaments.
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.
authors.affiliation: Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22908-0733, USA.
authors.forename: Albina
authors.initials: A
authors.lastname: Orlova
authors.forename: Ethan C
authors.initials: EC
authors.lastname: Garner
authors.forename: Vitold E
authors.initials: VE
authors.lastname: Galkin
authors.forename: John
authors.initials: J
authors.lastname: Heuser
authors.forename: R Dyche
authors.initials: RD
authors.lastname: Mullins
authors.forename: Edward H
authors.initials: EH
authors.lastname: Egelman
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D020285:Cryoelectron Microscopy; D004926:Escherichia coli / Q000737:chemistry; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020836:Protein Structure, Quaternary; D021122:Protein Subunits / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D000199:Actins; D029968:Escherichia coli Proteins; C471255:ParM protein, E coli; D021122:Protein Subunits