Faculty, Staff and Student Publications
Publication Date
11-1-2024
Journal
FEBS Letters
DOI
10.1002/1873-3468.15011
PMID
39245885
PMCID
PMC11560498
PubMedCentral® Posted Date
11-1-2025
PubMedCentral® Full Text Version
Author MSS
Abstract
Conjugative dissemination of mobile genetic elements (MGEs) among bacteria is initiated by assembly of the relaxosome at the MGE’s origin-of-transfer (oriT) sequence. A critical but poorly defined step of relaxosome assembly involves recruitment of the catalytic relaxase to its DNA strand-specific nicking site within oriT. Here, we present evidence by AlphaFold modeling, affinity pulldowns, and in vivo site-directed photocrosslinking that the TraK Ribbon-Helix-Helix DNA-binding protein recruits TraI to oriT through a dynamic interaction in which TraI’s C-terminal unstructured domain (TraICTD) wraps around TraK’s C-proximal tetramerization domain. Upon relaxosome assembly, conformational changes disrupt this contact, and TraICTD instead self-associates as a prerequisite for relaxase catalytic functions or substrate engagement with the transfer channel. These findings delineate key early-stage processing reactions required for conjugative dissemination of a model MGE.
Keywords
Escherichia coli Proteins, Conjugation, Genetic, Escherichia coli, Plasmids, DNA-Binding Proteins, Models, Molecular, Protein Binding, DNA Helicases, Conjugation, horizontal DNA transfer, mobile genetic elements, antibiotic resistance, type IV secretion, AlphaFold, photocrosslinking, Ribbon-Helix-Helix, relaxase
Published Open-Access
yes
Recommended Citation
Li, Yang Grace; Breidenstein, Annika; Berntsson, Ronnie P-A; et al., "Conjugative Transfer of the IncN Plasmid pKM101 Is Mediated by Dynamic Interactions Between the TraK Accessory Factor and TraI Relaxase" (2024). Faculty, Staff and Student Publications. 3722.
https://digitalcommons.library.tmc.edu/uthmed_docs/3722