6PPJ

Cryo-EM structure of AdnA(D934A)-AdnB(D1014A) in complex with AMPPNP

6PPJ の概要

• エントリーDOI: 10.2210/pdb6ppj/pdb
• EMDBエントリー: 20440
• 分子名称: UvrD/REP helicase, ATP-dependent DNA helicase (UvrD/REP), IRON/SULFUR CLUSTER, ... (4 entities in total)
• 機能のキーワード: dna binding protein
• 由来する生物種: Mycobacterium smegmatis; 詳細
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 226493.34

構造登録者

Jia, N.,Unciuleac, M.,Shuman, S.,Patel, D.J. (登録日: 2019-07-07, 公開日: 2019-11-20, 最終更新日: 2024-03-20)

主引用文献

Jia, N.,Unciuleac, M.C.,Xue, C.,Greene, E.C.,Patel, D.J.,Shuman, S.
Structures and single-molecule analysis of bacterial motor nuclease AdnAB illuminate the mechanism of DNA double-strand break resection.
Proc.Natl.Acad.Sci.USA, 116:24507-24516, 2019

PubMed Abstract: Mycobacterial AdnAB is a heterodimeric helicase-nuclease that initiates homologous recombination by resecting DNA double-strand breaks (DSBs). The AdnA and AdnB subunits are each composed of an N-terminal motor domain and a C-terminal nuclease domain. Here we report cryoelectron microscopy (cryo-EM) structures of AdnAB in three functional states: in the absence of DNA and in complex with forked duplex DNAs before and after cleavage of the 5' single-strand DNA (ssDNA) tail by the AdnA nuclease. The structures reveal the path of the 5' ssDNA through the AdnA nuclease domain and the mechanism of 5' strand cleavage; the path of the 3' tracking strand through the AdnB motor and the DNA contacts that couple ATP hydrolysis to mechanical work; the position of the AdnA iron-sulfur cluster subdomain at the Y junction and its likely role in maintaining the split trajectories of the unwound 5' and 3' strands. Single-molecule DNA curtain analysis of DSB resection reveals that AdnAB is highly processive but prone to spontaneous pausing at random sites on duplex DNA. A striking property of AdnAB is that the velocity of DSB resection slows after the enzyme experiences a spontaneous pause. Our results highlight shared as well as distinctive properties of AdnAB vis-à-vis the RecBCD and AddAB clades of bacterial DSB-resecting motor nucleases.

PubMed: 31740608
DOI: 10.1073/pnas.1913546116

実験手法

ELECTRON MICROSCOPY (3.5 Å)