TraN variants mediate conjugation species specificity of IncA/C, IncH and Acinetobacter baumannii plasmids
Author(s)
Type
Journal Article
Abstract
IncA/C and IncH plasmids commonly carry antimicrobial resistance genes, notably blaNDM-1. Although these plasmids disseminate among Gram-negative pathogens via conjugation, the mechanisms underlying mating pair stabilisation (MPS) and conjugation species specificity
remain poorly understood. In IncF plasmids, MPS is mediated by interactions between outer membrane proteins (OMP) encoded by the plasmids in the donor (TraN) and by the chromosome in the recipient. Using the Plascad database, we extracted 1,436 TraN sequences from 1517 plasmids: 62.5% (898/1,436), mainly in IncF plasmids, are 550–660aa (we renamed TraN short, TraNS); 15% (216/1,436), in IncA/C plasmids, are 880–950aa (TraN medium, TraNM); and 11% (160/1,436), in IncH plasmids, are 1,050–1,070aa (TraN long, TraNL). One TraN, found in six plasmids from Acinetobacter baumannii (891aa), was designated TraN V-shaped (TraNV). Like TraNS, TraNM and TraNL contain a base and one distal tip domain essential for conjugation, whereas TraNV has a base and two distinct tip domains forming a V-shaped structure. TraNM, TraNL and TraNV determine conjugation species specificity, with TraNL cooperating with OmpA. Tip swapping reverses conjugation specificity, revealing how TraNM and TraNL diversity influence plasmid host range and AMR dissemination. Our new data reveal the molecular basis of plasmid host specificity and broaden our understanding of how conjugation drives the dissemination of antimicrobial resistance genes among clinically relevant bacteria.
remain poorly understood. In IncF plasmids, MPS is mediated by interactions between outer membrane proteins (OMP) encoded by the plasmids in the donor (TraN) and by the chromosome in the recipient. Using the Plascad database, we extracted 1,436 TraN sequences from 1517 plasmids: 62.5% (898/1,436), mainly in IncF plasmids, are 550–660aa (we renamed TraN short, TraNS); 15% (216/1,436), in IncA/C plasmids, are 880–950aa (TraN medium, TraNM); and 11% (160/1,436), in IncH plasmids, are 1,050–1,070aa (TraN long, TraNL). One TraN, found in six plasmids from Acinetobacter baumannii (891aa), was designated TraN V-shaped (TraNV). Like TraNS, TraNM and TraNL contain a base and one distal tip domain essential for conjugation, whereas TraNV has a base and two distinct tip domains forming a V-shaped structure. TraNM, TraNL and TraNV determine conjugation species specificity, with TraNL cooperating with OmpA. Tip swapping reverses conjugation specificity, revealing how TraNM and TraNL diversity influence plasmid host range and AMR dissemination. Our new data reveal the molecular basis of plasmid host specificity and broaden our understanding of how conjugation drives the dissemination of antimicrobial resistance genes among clinically relevant bacteria.
Date Issued
2026-04-23
Date Acceptance
2026-02-11
Citation
Journal of Bacteriology, 2026, 208 (4)
ISSN
0021-9193
Publisher
American Society for Microbiology
Journal / Book Title
Journal of Bacteriology
Volume
208
Issue
4
Copyright Statement
© 2026 He et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.
License URL
Identifier
10.1128/jb.00536-25
Publication Status
Published
Article Number
ARTN e00536-25
Date Publish Online
2026-03-19