Cryo-EM structure and evolutionary history of the conjugation surface exclusion protein TraT

作者：Chloe Seddon, Sophia David, Joshua L. C. Wong, Naito Ishimoto, Shan He, Jonathan Bradshaw, Wen Wen Low, Gad Frankel, Konstantinos Beis · 发表于：Nature Communications · 年份：2025 · DOI：10.1038/s41467-025-55834-w · 被引用次数：13 · 研究领域：Antibiotic Resistance in Bacteria、Legionella and Acanthamoeba research、Infections and bacterial resistance

Abstract Conjugation plays a major role in dissemination of antimicrobial resistance genes. Following transfer of IncF-like plasmids, recipients become refractory to a second wave of conjugation with the same plasmid via entry (TraS) and surface (TraT) exclusion mechanisms. Here, we show that TraT from the pKpQIL and F plasmids (TraT pKpQIL and TraT F ) exhibits plasmid surface exclusion specificity. The cryo-EM structures of TraT pKpQIL and TraT F reveal that they oligomerise into decameric champagne bottle cork-like structures, which are anchored to the outer membrane via a diacylglycerol and palmitic acid modified α-helical barrel domain. Unexpectedly, we identify chromosomal TraT homologues from multiple Gram-negative phyla which form numerous divergent lineages in a phylogenetic tree of TraT sequences. Plasmid-associated TraT sequences are found in multiple distinct lineages, including two separate clades incorporating TraT from Enterobacteriaceae IncF/F-like and Legionellaceae F-like plasmids. These findings suggest that different plasmid backbones have acquired and co-opted TraT on independent occasions.