Yui Eto, K, Kwong, SM, LaBreck, PT, Crow, JE, Traore, DAK, Parahitiyawa, N, Fairhurst, HM, Merrell, DS, Firth, N, Bond, CS and Ramsay, JP (2021) Evolving origin-of-transfer sequences on staphylococcal conjugative and mobilizable plasmids—who’s mimicking whom? Nucleic Acids Research, 49 (9). 5177 - 5188. ISSN 0305-1048

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<jats:title>Abstract</jats:title> <jats:p>In Staphylococcus aureus, most multiresistance plasmids lack conjugation or mobilization genes for horizontal transfer. However, most are mobilizable due to carriage of origin-of-transfer (oriT) sequences mimicking those of conjugative plasmids related to pWBG749. pWBG749-family plasmids have diverged to carry five distinct oriT subtypes and non-conjugative plasmids have been identified that contain mimics of each. The relaxasome accessory factor SmpO, encoded by each conjugative plasmid, determines specificity for its cognate oriT. Here we characterized the binding of SmpO proteins to each oriT. SmpO proteins predominantly formed tetramers in solution and bound 5′-GNNNNC-3′ sites within each oriT. Four of the five SmpO proteins specifically bound their cognate oriT. An F7K substitution in pWBG749 SmpO switched oriT-binding specificity in vitro. In vivo, the F7K substitution reduced but did not abolish self-transfer of pWBG749. Notably, the substitution broadened the oriT subtypes that were mobilized. Thus, this substitution represents a potential evolutionary intermediate with promiscuous DNA-binding specificity that could facilitate a switch between oriT specificities. Phylogenetic analysis suggests pWBG749-family plasmids have switched oriT specificity more than once during evolution. We hypothesize the convergent evolution of oriT specificity in distinct branches of the pWBG749-family phylogeny reflects indirect selection pressure to mobilize plasmids carrying non-cognate oriT-mimics.</jats:p>

Item Type: Article
Additional Information: © The Author(s) 2021. Published by Oxford University Press on behalf of Nucleic Acids Research. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
Subjects: Q Science > Q Science (General)
Q Science > QD Chemistry
Q Science > QR Microbiology
Divisions: Faculty of Natural Sciences > School of Life Sciences
Depositing User: Symplectic
Date Deposited: 27 Jul 2021 11:46
Last Modified: 27 Jul 2021 11:46
URI: https://eprints.keele.ac.uk/id/eprint/9834

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