Convergent evolution involving dimeric and trimeric dUTPases in pathogenicity island mobilization.

24 páginas, 6 figuras, 3 tablasThe dUTPase (Dut) enzymes, encoded by almost all free-living organisms and some viruses, prevent the misincorporation of uracil into DNA. We previously proposed that trimeric Duts are regulatory proteins involved in different cellular processes; including the phage-mediated transfer of the Staphylococcus aureus pathogenicity island SaPIbov1. Recently, it has been shown that the structurally unrelated dimeric Dut encoded by phage ϕNM1 is similarly able to mobilize SaPIbov1, suggesting dimeric Duts could also be regulatory proteins. How this is accomplished remains unsolved. Here, using in vivo, biochemical and structural approaches, we provide insights into the signaling mechanism used by the dimeric Duts to induce the SaPIbov1 cycle. As reported for the trimeric Duts, dimeric Duts contain an extremely variable region, here named domain VI, which is involved in the regulatory capacity of these enzymes. Remarkably, our results also show that the dimeric Dut signaling mechanism is modulated by dUTP, as with the trimeric Duts. Overall, our results demonstrate that although unrelated both in sequence and structure, dimeric and trimeric Duts control SaPI transfer by analogous mechanisms, representing a fascinating example of convergent evolution. This conserved mode of action highlights the biological significance of Duts as regulatory molecules.This work was supported by grants, BIO2013-42619-P and BIO2016-78571-P, from the Ministerio de Economia y Competitividad (Spain) and grant Prometeo II/2014/029 from Valencian Government (Spain) to AM, and grants MR/M003876/1 from the Medical Research Council (UK), BB/N002873/1, from the Biotechnology and Biological Sciences Research Council (BBSRC, UK), and ERC-ADG-2014 Proposal n° 670932 Dut-signal from EU to JRP. EM was supported by CSIC JAE-Doc postdoctoral contract (Programa «Junta para la Ampliación de Estudios») co-funded by the European Social Fund. JRC and CA were supported by FPU13/02880 and FPI BES-2014-068617 predoctoral fellowships respectively. X-ray diffraction data collection was supported by Diamond Light Source block allocation group (BAG) Proposal, MX14739, and Spanish Synchrotron Radiation Facility ALBA Proposal 2016071762. The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under BioStruct-X, grant agreement N°283570. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewe