Discovery of a new family of relaxases in Firmicutes bacteria.
Antibiotic resistance is a serious global problem. Antibiotic resistance genes (ARG), which are widespread in environmental bacteria, can be transferred to pathogenic bacteria via horizontal gene transfer (HGT). Gut microbiomes are especially apt for the emergence and dissemination of ARG. Conjugati...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2017-02-01
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| Series: | PLoS Genetics |
| Online Access: | http://europepmc.org/articles/PMC5313138?pdf=render |
| _version_ | 1819132295794130944 |
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| author | Gayetri Ramachandran Andrés Miguel-Arribas David Abia Praveen K Singh Isidro Crespo César Gago-Córdoba Jian An Hao Juan Roman Luque-Ortega Carlos Alfonso Ling J Wu D Roeland Boer Wilfried J J Meijer |
| author_facet | Gayetri Ramachandran Andrés Miguel-Arribas David Abia Praveen K Singh Isidro Crespo César Gago-Córdoba Jian An Hao Juan Roman Luque-Ortega Carlos Alfonso Ling J Wu D Roeland Boer Wilfried J J Meijer |
| author_sort | Gayetri Ramachandran |
| collection | DOAJ |
| description | Antibiotic resistance is a serious global problem. Antibiotic resistance genes (ARG), which are widespread in environmental bacteria, can be transferred to pathogenic bacteria via horizontal gene transfer (HGT). Gut microbiomes are especially apt for the emergence and dissemination of ARG. Conjugation is the HGT route that is predominantly responsible for the spread of ARG. Little is known about conjugative elements of Gram-positive bacteria, including those of the phylum Firmicutes, which are abundantly present in gut microbiomes. A critical step in the conjugation process is the relaxase-mediated site- and strand-specific nick in the oriT region of the conjugative element. This generates a single-stranded DNA molecule that is transferred from the donor to the recipient cell via a connecting channel. Here we identified and characterized the relaxosome components oriT and the relaxase of the conjugative plasmid pLS20 of the Firmicute Bacillus subtilis. We show that the relaxase gene, named relLS20, is essential for conjugation, that it can function in trans and provide evidence that Tyr26 constitutes the active site residue. In vivo and in vitro analyses revealed that the oriT is located far upstream of the relaxase gene and that the nick site within oriT is located on the template strand of the conjugation genes. Surprisingly, the RelLS20 shows very limited similarity to known relaxases. However, more than 800 genes to which no function had been attributed so far are predicted to encode proteins showing significant similarity to RelLS20. Interestingly, these putative relaxases are encoded almost exclusively in Firmicutes bacteria. Thus, RelLS20 constitutes the prototype of a new family of relaxases. The identification of this novel relaxase family will have an important impact in different aspects of future research in the field of HGT in Gram-positive bacteria in general, and specifically in the phylum of Firmicutes, and in gut microbiome research. |
| first_indexed | 2024-12-22T09:29:08Z |
| format | Article |
| id | doaj.art-0bb180600a96476abef56dfac9445a0c |
| institution | Directory Open Access Journal |
| issn | 1553-7390 1553-7404 |
| language | English |
| last_indexed | 2024-12-22T09:29:08Z |
| publishDate | 2017-02-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS Genetics |
| spelling | doaj.art-0bb180600a96476abef56dfac9445a0c2022-12-21T18:30:59ZengPublic Library of Science (PLoS)PLoS Genetics1553-73901553-74042017-02-01132e100658610.1371/journal.pgen.1006586Discovery of a new family of relaxases in Firmicutes bacteria.Gayetri RamachandranAndrés Miguel-ArribasDavid AbiaPraveen K SinghIsidro CrespoCésar Gago-CórdobaJian An HaoJuan Roman Luque-OrtegaCarlos AlfonsoLing J WuD Roeland BoerWilfried J J MeijerAntibiotic resistance is a serious global problem. Antibiotic resistance genes (ARG), which are widespread in environmental bacteria, can be transferred to pathogenic bacteria via horizontal gene transfer (HGT). Gut microbiomes are especially apt for the emergence and dissemination of ARG. Conjugation is the HGT route that is predominantly responsible for the spread of ARG. Little is known about conjugative elements of Gram-positive bacteria, including those of the phylum Firmicutes, which are abundantly present in gut microbiomes. A critical step in the conjugation process is the relaxase-mediated site- and strand-specific nick in the oriT region of the conjugative element. This generates a single-stranded DNA molecule that is transferred from the donor to the recipient cell via a connecting channel. Here we identified and characterized the relaxosome components oriT and the relaxase of the conjugative plasmid pLS20 of the Firmicute Bacillus subtilis. We show that the relaxase gene, named relLS20, is essential for conjugation, that it can function in trans and provide evidence that Tyr26 constitutes the active site residue. In vivo and in vitro analyses revealed that the oriT is located far upstream of the relaxase gene and that the nick site within oriT is located on the template strand of the conjugation genes. Surprisingly, the RelLS20 shows very limited similarity to known relaxases. However, more than 800 genes to which no function had been attributed so far are predicted to encode proteins showing significant similarity to RelLS20. Interestingly, these putative relaxases are encoded almost exclusively in Firmicutes bacteria. Thus, RelLS20 constitutes the prototype of a new family of relaxases. The identification of this novel relaxase family will have an important impact in different aspects of future research in the field of HGT in Gram-positive bacteria in general, and specifically in the phylum of Firmicutes, and in gut microbiome research.http://europepmc.org/articles/PMC5313138?pdf=render |
| spellingShingle | Gayetri Ramachandran Andrés Miguel-Arribas David Abia Praveen K Singh Isidro Crespo César Gago-Córdoba Jian An Hao Juan Roman Luque-Ortega Carlos Alfonso Ling J Wu D Roeland Boer Wilfried J J Meijer Discovery of a new family of relaxases in Firmicutes bacteria. PLoS Genetics |
| title | Discovery of a new family of relaxases in Firmicutes bacteria. |
| title_full | Discovery of a new family of relaxases in Firmicutes bacteria. |
| title_fullStr | Discovery of a new family of relaxases in Firmicutes bacteria. |
| title_full_unstemmed | Discovery of a new family of relaxases in Firmicutes bacteria. |
| title_short | Discovery of a new family of relaxases in Firmicutes bacteria. |
| title_sort | discovery of a new family of relaxases in firmicutes bacteria |
| url | http://europepmc.org/articles/PMC5313138?pdf=render |
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