title: Structural basis for DNA 5´-end resection by RecJ.
abstract: The resection of DNA strand with a 5´ end at double-strand breaks is an essential step in recombinational DNA repair. RecJ, a member of DHH family proteins, is the only 5´ nuclease involved in the RecF recombination pathway. Here, we report the crystal structures of Deinococcus radiodurans RecJ in complex with deoxythymidine monophosphate (dTMP), ssDNA, the C-terminal region of single-stranded DNA-binding protein (SSB-Ct) and a mechanistic insight into the RecF pathway. A terminal 5´-phosphate-binding pocket above the active site determines the 5´-3´ polarity of the deoxy-exonuclease of RecJ; a helical gateway at the entrance to the active site admits ssDNA only; and the continuous stacking interactions between protein and nine nucleotides ensure the processive end resection. The active site of RecJ in the N-terminal domain contains two divalent cations that coordinate the nucleophilic water. The ssDNA makes a 180° turn at the scissile phosphate. The C-terminal domain of RecJ binds the SSB-Ct, which explains how RecJ and SSB work together to efficiently process broken DNA ends for homologous recombination.
authors.affiliation: Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Kaiying
authors.initials: K
authors.lastname: Cheng
authors.affiliation: Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
authors.affiliation: Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Xuanyi
authors.initials: X
authors.lastname: Chen
authors.affiliation: Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Liangyan
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Tian
authors.affiliation: Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Ye
authors.identifier: http://orcid.org/0000-0002-5455-2586
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Yuejin
authors.initials: Y
authors.lastname: Hua
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D004269:DNA, Bacterial / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D034301:Deinococcus / Q000201:enzymology*; D005090:Exodeoxyribonucleases / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D013938:Thymidine Monophosphate / Q000737:chemistry / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D013938:Thymidine Monophosphate; D005090:Exodeoxyribonucleases; C070765:recJ protein, Bacteria
keywords: DNA end resection; Deinococcus radiodurans; RecF pathway; RecJ; biophysics; single-strand-DNA binding protein; structural biology; two-metal-ion catalysis