Download MendeleyStructural basis of chiral wrap and T-segment capture by Escherichia coli DNA gyrase.
Michalczyk, E., Pakosz-Stepien, Z., Liston, J.D., Gittins, O., Pabis, M., Heddle, J.G., Ghilarov, D.(2024) Proc Natl Acad Sci U S A 121: e2407398121-e2407398121
- PubMed: 39589884
- DOI: https://doi.org/10.1073/pnas.2407398121
- Primary Citation of Related Structures:
9GGQ - PubMed Abstract:
Type II topoisomerase DNA gyrase transduces the energy of ATP hydrolysis into the negative supercoiling of DNA. The postulated catalytic mechanism involves stabilization of a chiral DNA loop followed by the passage of the T-segment through the temporarily cleaved G-segment resulting in sign inversion. The molecular basis for this is poorly understood as the chiral loop has never been directly observed. We have obtained high-resolution cryoEM structures of Escherichia coli gyrase with chirally wrapped 217 bp DNA with and without the fluoroquinolone moxifloxacin (MFX). Each structure constrains a positively supercoiled figure-of-eight DNA loop stabilized by a GyrA β-pinwheel domain which has the structure of a flat disc. By comparing the catalytic site of the native drug-free and MFX-bound gyrase structures both of which contain a single metal ion, we demonstrate that the enzyme is observed in a native precatalytic state. Our data imply that T-segment trapping is not dependent on the dimerization of the ATPase domains which appears to only be possible after strand passage has taken place.
Organizational Affiliation:
Doctoral School of Exact and Natural Sciences, Jagiellonian University, Kraków 30-348, Poland.
