Working Paper Article Version 2 This version is not peer-reviewed

Functional Analysis of the Acinetobacter baumannii XerC and XerD Site-Specific Recombinases: Potential Role in Dissemination of Resistance Genes

Version 1 : Received: 12 June 2020 / Approved: 14 June 2020 / Online: 14 June 2020 (03:51:54 CEST)
Version 2 : Received: 9 July 2020 / Approved: 10 July 2020 / Online: 10 July 2020 (02:10:07 CEST)

A peer-reviewed article of this Preprint also exists.

Lin, D.L.; Traglia, G.M.; Baker, R.; Sherratt, D.J.; Ramirez, M.S.; Tolmasky, M.E. Functional Analysis of the Acinetobacter baumannii XerC and XerD Site-Specific Recombinases: Potential Role in Dissemination of Resistance Genes. Antibiotics 2020, 9, 405. Lin, D.L.; Traglia, G.M.; Baker, R.; Sherratt, D.J.; Ramirez, M.S.; Tolmasky, M.E. Functional Analysis of the Acinetobacter baumannii XerC and XerD Site-Specific Recombinases: Potential Role in Dissemination of Resistance Genes. Antibiotics 2020, 9, 405.

Journal reference: Antibiotics 2020, 9, 405
DOI: 10.3390/antibiotics9070405

Abstract

Modules composed of a resistance gene flanked by Xer site-specific recombination sites, the vast majority of which were found in Acinetobacter baumannii, are thought to behave as elements that facilitate horizontal dissemination. The A. baumannii xerC and xerD genes were cloned, and the recombinant clones used to complement the cognate Escherichia coli mutants. The complemented strains supported resolution of plasmid dimers, and, as is the case with E. coli and Klebsiella pneumoniae plasmids, the activity was enhanced when cells were growing in low osmolarity growth medium. Binding experiments showed that partially purified A. baumannii XerC and XerD proteins (XerCAb and XerDAb) bound synthetic Xer site-specific recombination sites, some of them with a nucleotide sequence deduced from existing A. baumannii plasmids. Incubation with suicide substrates resulted in covalent attachment of DNA to a recombinase, probably XerCAb, indicating that the first step in the recombination reaction took place. The results described show that XerCAb and XerDAb are functional proteins and support the hypothesis that they participate in horizontal dissemination of resistant genes among bacteria.

Subject Areas

site-specific recombination; carbapenemase; ESKAPE; Acinetobacter; plasmid; Xer; dif; pdif; Re27; gene transfer; gene dissemination; horizontal transfer; horizontal dissemination

Comments (1)

Comment 1
Received: 10 July 2020
Commenter: Marcelo Tolmasky
Commenter's Conflict of Interests: Author
Comment: Modifications to respond to reviewers' questions and suggestions.
Addition of Supplemental Material containing a comparative analysis of the xerC and xerD genes from A> baumannii strains and SDS-PAGE gels of the partial purification of XerC and XerD
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