2026-10-15T17:13:56Z https://data.mendeley.com/oai

oai:data.mendeley.com/8cw3ygfssy.1 2024-11-28T16:00:00Z

McLean, Thomas KorB switching from DNA-sliding clamp to repressor mediates long-range gene silencing in a multi-drug resistance plasmid Mendeley Data Examples of long-range gene regulation in bacteria are rare and generally thought to involve DNA looping. Here, using a combination of biophysical approaches including X-ray crystallography and single-molecule analysis for the KorB-KorA system in Escherichia coli, we show that long-range gene silencing on the plasmid RK2, a source of multi-drug resistance across diverse Gram-negative bacteria, is achieved cooperatively by a DNA-sliding clamp, KorB, and a clamp-locking protein, KorA. We show that KorB is a CTPase clamp that can entrap and slide along DNA to reach distal target promoters up to 1.5 kb away. We resolved the tripartite crystal structure of a KorB-KorA-DNA co-complex, revealing that KorA latches KorB into a closed clamp state. DNA-bound KorA thus stimulates repression by stalling KorB sliding at target promoters to occlude RNA polymerase holoenzymes. Together, our findings explain the mechanistic basis for KorB role switching from a DNA-sliding clamp to a co-repressor, and provide an alternative mechanism for long-range regulation of gene expression in bacteria. Biochemistry Structural Biology Mass Spectrometry Plasmid Single Molecule Imaging Molecular Microbiology Balaguer Pérez, Francisco Chandanani, Joshua Thomas, Christopher Aicart-Ramos, Clara Burick, Sophia Olinares, Paul Gobbato, Giulia Mundy, Julia Chait, Brian Lawson, David Darst, Seth Campbell, Elizabeth Moreno-Herrero, Fernando Le, Tung Dataset doi:10.17632/8cw3ygfssy.1 oai:data.mendeley.com/8cw3ygfssy.1 Creative Commons Attribution 4.0 International http://creativecommons.org/licenses/by/4.0 https://data.mendeley.com/datasets/8cw3ygfssy 2024-11-28T16:00:00Z