Processing of Nonconjugative Resistance Plasmids by Conjugation Nicking Enzyme of Staphylococci
| Autor: | Thomas C. Eakes, Joshua P. Ramsay, Karina Yui Eto, Neville Firth, Rebecca M. Pollet, Stephen M. Kwong, Matthew R. Redinbo, Jeffrey P. Hymes, James D. Ingle |
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| Rok vydání: | 2015 |
| Předmět: |
0301 basic medicine
DNA Bacterial Origin of transfer Staphylococcus aureus Gene Transfer Horizontal 030106 microbiology Replication Origin Biology Relaxase Microbiology 03 medical and health sciences Plasmid Bacterial Proteins DNA Breaks Single-Stranded Molecular Biology Genetics Nicking enzyme Articles Relaxosome Endonucleases Multiple drug resistance Conjugation Genetic Horizontal gene transfer Nucleic Acid Conformation Trans-acting Plasmids Protein Binding |
| Zdroj: | Journal of bacteriology. 198(6) |
| ISSN: | 1098-5530 |
| Popis: | Antimicrobial resistance in Staphylococcus aureus presents an increasing threat to human health. This resistance is often encoded on mobile plasmids, such as pSK41; however, the mechanism of transfer of these plasmids is not well understood. In this study, we first examine key protein-DNA interactions formed by the relaxase enzyme, NES, which initiates and terminates the transfer of the multidrug resistance plasmid pSK41. Two loops on the NES protein, hairpin loops 1 and 2, form extensive contacts with the DNA hairpin formed at the oriT region of pSK41, and here we establish that these contacts are essential for proper DNA cleavage and religation by the full 665-residue NES protein in vitro . Second, pSK156 and pCA347 are nonconjugative Staphylococcus aureus plasmids that contain sequences similar to the oriT region of pSK41 but differ in the sequence predicted to form a DNA hairpin. We show that pSK41-encoded NES is able to bind, cleave, and religate the oriT sequences of these nonconjugative plasmids in vitro . Although pSK41 could mobilize a coresident plasmid harboring its cognate oriT , it was unable to mobilize plasmids containing the pSK156 and pCA347 variant oriT mimics, suggesting that an accessory protein like that previously shown to confer specificity in the pWBG749 system may also be involved in transmission of plasmids containing a pSK41-like oriT . These data indicate that the conjugative relaxase in trans mechanism recently described for the pWBG749 family of plasmids also applies to the pSK41 family of plasmids, further heightening the potential significance of this mechanism in the horizontal transfer of staphylococcal plasmids. IMPORTANCE Understanding the mechanism of antimicrobial resistance transfer in bacteria such as Staphylococcus aureus is an important step toward potentially slowing the spread of antimicrobial-resistant infections. This work establishes protein-DNA interactions essential for the transfer of the Staphylococcus aureus multiresistance plasmid pSK41 by its relaxase, NES. This enzyme also processed variant oriT -like sequences found on numerous plasmids previously considered nontransmissible, suggesting that in conjunction with an uncharacterized accessory protein, these plasmids may be transferred horizontally via a relaxase in trans mechanism. These findings have important implications for our understanding of staphylococcal resistance plasmid evolution. |
| Databáze: | OpenAIRE |
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