title: ATPase activity tightly regulates RecA nucleofilaments to promote homologous recombination.
abstract: Homologous recombination (HR), catalyzed in an evolutionarily conserved manner by active RecA/Rad51 nucleofilaments, maintains genomic integrity and promotes biological evolution and diversity. The structures of RecA/Rad51 nucleofilaments provide information critical for the entire HR process. By exploiting a unique capillary electrophoresis-laser-induced fluorescence polarization assay, we have discovered an active form of RecA nucleofilament, stimulated by ATP hydrolysis, that contains mainly unbound nucleotide sites. This finding was confirmed by a nuclease protection assay and electron microscopy (EM) imaging. We further found that these RecA-unsaturated filaments promote strand exchangein vitroand HRin vivo. RecA mutants (P67D and P67E), which only form RecA-unsaturated nucleofilaments, were able to mediate HRin vitroandin vivo, but mutants favoring the formation of the saturated nucleofilaments failed to support HR. We thus present a new model for RecA-mediated HR in which RecA utilizes its intrinsic DNA binding-dependent ATPase activity to remodel the nucleofilaments to a less saturated form and thereby promote HR.
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing, China.
authors.forename: Bailin
authors.initials: B
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing, China.
authors.forename: Dapeng
authors.initials: D
authors.lastname: Zhang
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences , Beijing, China.
authors.forename: Chengmin
authors.initials: C
authors.lastname: Li
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Yuan
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing, China.
authors.forename: Fangzhi
authors.initials: F
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing, China.
authors.forename: Shangwei
authors.initials: S
authors.lastname: Zhong
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing, China.
authors.forename: Guibin
authors.initials: G
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Genomics and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences , Beijing, China.
authors.forename: Yun-Gui
authors.identifier: 0000-0002-2821-8541
authors.initials: YG
authors.lastname: Yang
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta , Edmonton, AB, Canada.
authors.forename: X Chris
authors.initials: XC
authors.lastname: Le
authors.affiliation: Experimental Oncology, Cross Cancer Institute and University of Alberta , Edmonton, AB, Canada.
authors.forename: Michael
authors.identifier: 0000-0002-8773-1425
authors.initials: M
authors.lastname: Weinfeld
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences , Beijing, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing, China.
authors.forename: Hailin
authors.initials: H
authors.lastname: Wang
keywords: ATPase activity; RecA; capillary electrophoresis; homologous recombination; laser-induced fluorescence polarization; strand exchange