title: Structure of the ParM filament at 8.5Å resolution.
abstract: The actin-like protein ParM forms the cytomotive filament of the ParMRC system, a type II plasmid segregation system encoded by Escherichia coli R1 plasmid. We report an 8.5Å resolution reconstruction of the ParM filament, obtained using cryo-electron microscopy. Fitting of the 3D density reconstruction with monomeric crystal structures of ParM provides insights into dynamic instability of ParM filaments. The structural analysis suggests that a ParM conformation, corresponding to a metastable state, is held within the filament by intrafilament contacts. This filament conformation of ParM can be attained only from the ATP-bound state, and induces a change in conformation of the bound nucleotide. The structural analysis also provides a rationale for the observed stimulation of hydrolysis upon polymerisation into the filament.
authors: MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK.
authors: Pananghat
authors: P
authors: Gayathri
authors: Takashi
authors: T
authors: Fujii
authors: Keiichi
authors: K
authors: Namba
authors: Jan
authors: J
authors: Löwe
mesh_terms: D008841:Actin Cytoskeleton / Q000737:chemistry*; D000199:Actins / Q000737:chemistry*; D020134:Catalytic Domain; D029968:Escherichia coli Proteins / Q000737:chemistry*; D006868:Hydrolysis; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D000199:Actins; D029968:Escherichia coli Proteins; C471255:ParM protein, E coli
keywords: Actin; Bacterial cytoskeleton; Cytomotive; Dynamic instability