A novel DNA primase-helicase pair encoded by SCCmec elements
- The University of Chicago, United States
Abstract
Mobile genetic elements (MGEs) are a rich source of new enzymes, and conversely, understanding the activities of MGE-encoded proteins can elucidate MGE function. Here we biochemically characterize 3 proteins encoded by a conserved operon carried by the Staphylococcal Cassette Chromosome (SCCmec), an MGE that confers methicillin resistance to Staphylococcus aureus, creating MRSA strains. The first of these proteins, CCPol, is an active A-family DNA polymerase. The middle protein, MP, binds tightly to CCPol and confers upon it the ability to synthesize DNA primers de novo. The CCPol-MP complex is therefore a unique primase-polymerase enzyme unrelated to either known primase family. The third protein, Cch2, is a 3'-to-5' helicase. Cch2 additionally binds specifically to a dsDNA sequence downstream of its gene that is also a preferred initiation site for priming by CCPol-MP. Taken together, our results suggest that this is a functional replication module for SCCmec.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files.
Article and author information
Author details
Ignacio Mir-Sanchis
Funding
National Institute of General Medical Sciences (R01 GM121655)
- Aleksandra Bebel
- Melissa A Walsh
- Ignacio Mir-Sanchis
- Phoebe A Rice
European Molecular Biology Organization (Long-Term Fellowship ALTF 65-2017)
- Aleksandra Bebel
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2020, Bebel et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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A novel DNA primase-helicase pair encoded by SCCmec elements
eLife 9:e55478.
https://doi.org/10.7554/eLife.55478
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