Title: Mechanisms of helicase activated DNA end resection in bacteria

Ying Xu, Lingyi Xu, Chen Qin, Liangyan Wang, Jiangtao Guo, Yuejin Hua, Ye Zhao

Published: July 15, 2022

DOI: https://doi.org/10.1016/j.str.2022.06.005

Summary

DNA end resection mediated by the coordinated action of nuclease and helicase is a crucial step in initiating homologous recombination. The end-resection apparatus NurA nuclease and HerA helicase are present in both archaea and bacteria. Here, we report the cryo-electron microscopy structure of a bacterial HerA-NurA complex from Deinococcus radiodurans. The structure reveals a barrel-like hexameric HerA and a distinctive NurA dimer subcomplex, which has a unique extended N-terminal region (ENR) involved in bacterial NurA dimerization and activation. In addition to the long protruding linking loop and the C-terminal α helix of NurA, the flexible ENR is close to the HerA-NurA interface and divides the central channel of the DrNurA dimer into two halves, suggesting a possible mechanism of DNA end processing. In summary, this work provides new insights into the structure, assembly, and activation mechanisms of bacterial DNA end resection mediated by a minimal end-resection apparatus.

Link:  https://www.cell.com/structure/fulltext/S0969-2126(22)00236-2