BACKGROUND: DnaB is the primary replicative helicase in Escherichia coli. Native DnaB is a hexamer of identical subunits, each consisting of a larger C-terminal domain and a smaller N-terminal domain. Electron-microscopy data show hexamers with C6 or C3 symmetry, indicating large domain movements and reversible pairwise association. RESULTS: The three-dimensional structure of the N-terminal domain of E. coli DnaB was determined by nuclear magnetic resonance (NMR) spectroscopy. Structural similarity was found with the primary dimerisation domain of a topoisomerase, the gyrase A subunit from E. coli. A monomer-dimer equilibrium was observed for the isolated N-terminal domain of DnaB. A dimer model with C2 symmetry was derived from intermolecular nuclear Overhauser effects, which is consistent with all available NMR data. CONCLUSIONS: The monomer-dimer equilibrium observed for the N-terminal domain of DnaB is likely to be of functional significance for helicase activity, by participating in the switch between C6 and C3 symmetry of the helicase hexamer.
BACKGROUND: DnaB is the primary replicative helicase in Escherichia coli. Native DnaB is a hexamer of identical subunits, each consisting of a larger C-terminal domain and a smaller N-terminal domain. Electron-microscopy data show hexamers with C6 or C3 symmetry, indicating large domain movements and reversible pairwise association. RESULTS: The three-dimensional structure of the N-terminal domain of E. coli DnaB was determined by nuclear magnetic resonance (NMR) spectroscopy. Structural similarity was found with the primary dimerisation domain of a topoisomerase, the gyrase A subunit from E. coli. A monomer-dimer equilibrium was observed for the isolated N-terminal domain of DnaB. A dimer model with C2 symmetry was derived from intermolecular nuclear Overhauser effects, which is consistent with all available NMR data. CONCLUSIONS: The monomer-dimer equilibrium observed for the N-terminal domain of DnaB is likely to be of functional significance for helicase activity, by participating in the switch between C6 and C3 symmetry of the helicase hexamer.
Authors: Andrew Robinson; Anthony J Brzoska; Kylie M Turner; Ryan Withers; Elizabeth J Harry; Peter J Lewis; Nicholas E Dixon Journal: Microbiol Mol Biol Rev Date: 2010-06 Impact factor: 11.056
Authors: Stephen J Watt; Margaret M Sheil; Jennifer L Beck; Pavel Prosselkov; Gottfried Otting; Nicholas E Dixon Journal: J Am Soc Mass Spectrom Date: 2007-06-19 Impact factor: 3.109
Authors: Faruck Morcos; Nicholas P Schafer; Ryan R Cheng; José N Onuchic; Peter G Wolynes Journal: Proc Natl Acad Sci U S A Date: 2014-08-11 Impact factor: 11.205
Authors: Argyris Politis; Ah Young Park; Suk-Joon Hyung; Daniel Barsky; Brandon T Ruotolo; Carol V Robinson Journal: PLoS One Date: 2010-08-10 Impact factor: 3.240