Publication Date

4-12-2024

Journal

Science

DOI

10.1126/science.adl5899

PMID

38603484

PMCID

PMC11108255

PubMedCentral® Posted Date

5-21-2024

PubMedCentral® Full Text Version

Author MSS

Published Open-Access

yes

Keywords

Cryoelectron Microscopy, DNA, DNA Gyrase, DNA, Superhelical, Escherichia coli, Escherichia coli Proteins, Protein Domains

Abstract

DNA supercoiling must be precisely regulated by topoisomerases to prevent DNA entanglement. The interaction of type IIA DNA topoisomerases with two DNA molecules, enabling the transport of one duplex through the transient double-stranded break of the other, remains elusive owing to structures derived solely from single linear duplex DNAs lacking topological constraints. Using cryo–electron microscopy, we solved the structure of Escherichia coli DNA gyrase bound to a negatively supercoiled minicircle DNA. We show how DNA gyrase captures a DNA crossover, revealing both conserved molecular grooves that accommodate the DNA helices. Together with molecular tweezer experiments, the structure shows that the DNA crossover is of positive chirality, reconciling the binding step of gyrase-mediated DNA relaxation and supercoiling in a single structure.

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