title: Listeria's right-handed helical rocket-tail trajectories: mechanistic implications for force generation in actin-based motility.
abstract: Listeria monocytogenes forms right-handed helical rocket tail trajectories during actin-based motility in cell-free extracts, and this stereochemical feature is consistent with actoclampin's affinity-modulated, clamped-filament elongation model [Dickinson and Purich, 2002: Biophys J 82:605-617]. In that mechanism, right-handed torque is generated by an end-tracking molecular motor, each comprised of a filament barbed end and clamping protein that processively traces the right-handed helix of its filament partner. By contrast, torque is not a predicted property of those models (e.g., elastic propulsion, elastic Brownian ratchet, tethered ratchet, and insertional polymerization models) requiring filament barbed ends to depart/detach from the motile object's surface during/after each monomer-addition step. Helical trajectories also explain why Listeria undergoes longitudinal-axis rotation on a length-scale matching the helical periodicity of Listeria's rocket tails.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610-0245, USA.
authors.forename: William L
authors.initials: WL
authors.lastname: Zeile
authors.forename: Fangliang
authors.initials: F
authors.lastname: Zhang
authors.forename: Richard B
authors.initials: RB
authors.lastname: Dickinson
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Purich
mesh_terms: D000199:Actins / Q000502:physiology*; D000818:Animals; D008089:Listeria monocytogenes / Q000502:physiology*; D009068:Movement / Q000502:physiology; D051381:Rats
chemical_list: D000199:Actins