title: Domain structure and dynamics in the helical filaments formed by RecA and Rad51 on DNA.
abstract: Both the bacterial RecA protein and the eukaryotic Rad51 protein form helical nucleoprotein filaments on DNA that catalyze strand transfer between two homologous DNA molecules. However, only the ATP-binding cores of these proteins have been conserved, and this same core is also found within helicases and the F1-ATPase. The C-terminal domain of the RecA protein forms lobes within the helical RecA filament. However, the Rad51 proteins do not have the C-terminal domain found in RecA, but have an N-terminal extension that is absent in the RecA protein. Both the RecA C-terminal domain and the Rad51 N-terminal domain bind DNA. We have used electron microscopy to show that the lobes of the yeast and human Rad51 filaments appear to be formed by N-terminal domains. These lobes are conformationally flexible in both RecA and Rad51. Within RecA filaments, the change between the "active" and "inactive" states appears to mainly involve a large movement of the C-terminal lobe. The N-terminal domain of Rad51 and the C-terminal domain of RecA may have arisen from convergent evolution to play similar roles in the filaments.
authors.affiliation: Department of Biochemistry and Molecular Genetics, University of Virginia Health Sciences Center, Box 800733, Charlottesville, VA 22908, USA.
authors.forename: X
authors.initials: X
authors.lastname: Yu
authors.forename: S A
authors.initials: SA
authors.lastname: Jacobs
authors.forename: S C
authors.initials: SC
authors.lastname: West
authors.forename: T
authors.initials: T
authors.lastname: Ogawa
authors.forename: E H
authors.initials: EH
authors.lastname: Egelman
mesh_terms: D004247:DNA / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000737:chemistry*; D006801:Humans; D008958:Models, Molecular; D017434:Protein Structure, Tertiary; D051135:Rad51 Recombinase; D011938:Rec A Recombinases / Q000737:chemistry*
chemical_list: D004268:DNA-Binding Proteins; D004247:DNA; C495153:RAD51 protein, human; D051135:Rad51 Recombinase; D011938:Rec A Recombinases