EMD-28101

Single-particle
2.97 Å
EMD-28101 Deposition: 09/09/2022
Map released: 10/05/2023
Last modified: 20/11/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-28101

Structure of single homo-hexameric Holliday junction ATP-dependent DNA helicase RuvB motor

EMD-28101

Single-particle
2.97 Å
EMD-28101 Deposition: 09/09/2022
Map released: 10/05/2023
Last modified: 20/11/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Thermus thermophilus HB8
Sample: Single homo-hexameric AAA+ ATPase RuvB motor
Fitted models: 8efv (Avg. Q-score: 0.556)

Deposition Authors: Shen ZF , Rish AD , Fu TM
Molecular mechanisms of Holliday junction branch migration catalyzed by an asymmetric RuvB hexamer.
Rish AD , Shen Z , Chen Z , Zhang N, Zheng Q , Fu TM
(2023) Nat Commun , 14 , 3549 - 3549
PUBMED: 37322069
DOI: doi:10.1038/s41467-023-39250-6
ISSN: 2041-1723
Abstract:
The Holliday junction (HJ) is a DNA intermediate of homologous recombination, involved in many fundamental physiological processes. RuvB, an ATPase motor protein, drives branch migration of the Holliday junction with a mechanism that had yet to be elucidated. Here we report two cryo-EM structures of RuvB, providing a comprehensive understanding of HJ branch migration. RuvB assembles into a spiral staircase, ring-like hexamer, encircling dsDNA. Four protomers of RuvB contact the DNA backbone with a translocation step size of 2 nucleotides. The variation of nucleotide-binding states in RuvB supports a sequential model for ATP hydrolysis and nucleotide recycling, which occur at separate, singular positions. RuvB's asymmetric assembly also explains the 6:4 stoichiometry between the RuvB/RuvA complex, which coordinates HJ migration in bacteria. Taken together, we provide a mechanistic understanding of HJ branch migration facilitated by RuvB, which may be universally shared by prokaryotic and eukaryotic organisms.