- EMDB-23954: Cryo-EM structure of RecBCD with undocked RecBNuc and flexible RecD -
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基本情報
登録情報
データベース: EMDB / ID: EMD-23954
タイトル
Cryo-EM structure of RecBCD with undocked RecBNuc and flexible RecD
マップデータ
試料
複合体: Heterotrimeric complex of RecBCD
タンパク質・ペプチド: RecBCD enzyme subunit RecB
タンパク質・ペプチド: RecBCD enzyme subunit RecC
タンパク質・ペプチド: RecBCD enzyme subunit RecD
キーワード
SF1 helicase / complex / DNA repair / motor protein / HYDROLASE
機能・相同性
機能・相同性情報
exodeoxyribonuclease V / exodeoxyribonuclease V activity / exodeoxyribonuclease V complex / clearance of foreign intracellular DNA / DNA translocase activity / DNA 5'-3' helicase / single-stranded DNA helicase activity / recombinational repair / 3'-5' DNA helicase activity / DNA 3'-5' helicase ...exodeoxyribonuclease V / exodeoxyribonuclease V activity / exodeoxyribonuclease V complex / clearance of foreign intracellular DNA / DNA translocase activity / DNA 5'-3' helicase / single-stranded DNA helicase activity / recombinational repair / 3'-5' DNA helicase activity / DNA 3'-5' helicase / ATP-dependent activity, acting on DNA / DNA helicase activity / DNA endonuclease activity / isomerase activity / helicase activity / double-strand break repair via homologous recombination / response to radiation / 5'-3' DNA helicase activity / DNA recombination / DNA damage response / magnesium ion binding / ATP hydrolysis activity / DNA binding / ATP binding / cytosol 類似検索 - 分子機能
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM045948
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R35 GM136632
米国
引用
ジャーナル: J Mol Biol / 年: 2021 タイトル: Heterogeneity in E. coli RecBCD Helicase-DNA Binding and Base Pair Melting. 著者: Linxuan Hao / Rui Zhang / Timothy M Lohman / 要旨: E. coli RecBCD, a helicase/nuclease involved in double stranded (ds) DNA break repair, binds to a dsDNA end and melts out several DNA base pairs (bp) using only its binding free energy. We examined ...E. coli RecBCD, a helicase/nuclease involved in double stranded (ds) DNA break repair, binds to a dsDNA end and melts out several DNA base pairs (bp) using only its binding free energy. We examined RecBCD-DNA initiation complexes using thermodynamic and structural approaches. Measurements of enthalpy changes for RecBCD binding to DNA ends possessing pre-melted ssDNA tails of increasing length suggest that RecBCD interacts with ssDNA as long as 17-18 nucleotides and can melt at least 10-11 bp upon binding a blunt DNA end. Cryo-EM structures of RecBCD alone and in complex with a blunt-ended dsDNA show significant conformational heterogeneities associated with the RecB nuclease domain (RecB) and the RecD subunit. In the absence of DNA, 56% of RecBCD molecules show no density for the RecB nuclease domain, RecB, and all RecBCD molecules show only partial density for RecD. DNA binding reduces these conformational heterogeneities, with 63% of the molecules showing density for both RecD and RecB. This suggests that the RecB domain is dynamic and influenced by DNA binding. The major RecBCD-DNA structural class in which RecB is docked onto RecC shows melting of at least 11 bp from a blunt DNA end, much larger than previously observed. A second structural class in which RecB is not docked shows only four bp melted suggesting that RecBCD complexes transition between states with different extents of DNA melting and that the extent of melting regulates initiation of helicase activity.