the dutpase enzyme is essential in mycobacterium smegmatisdutpase酶在smegmatis分枝杆菌至关重要.pdf

The dUTPase Enzyme Is Essential in Mycobacterium smegmatis 1,2 1 2 1 2 1,3 Ildiko Pecsi , Rita Hirmondo , Amanda C. Brown , Anna Lopata , Tanya Parish , Beata G. Vertessy *, ´ 1* Judit Toth 1 Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary, 2 Queen Mary University of London, Barts and the London School of Medicine and Dentistry, London, United Kingdom, 3 Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Budapest, Hungary Abstract Thymidine biosynthesis is essential in all cells. Inhibitors of the enzymes involved in this pathway (e.g. methotrexate) are thus frequently used as cytostatics. Due to its pivotal role in mycobacterial thymidylate synthesis dUTPase, which hydrolyzes dUTP into the dTTP precursor dUMP, has been suggested as a target for new antitubercular agents. All mycobacterial genomes encode dUTPase with a mycobacteria-specific surface loop absent in the human dUTPase. Using Mycobacterium smegmatis as a fast growing model for Mycobacterium tuberculosis, we demonstrate that dUTPase knock-out results in lethality that can be reverted by complementation with wild-type dUTPase. Interestingly, a mutant dUTPase gene lacking the genus-specific loop was unable to complement the knock-out phenotype. We also show that deletion of the mycobacteria-specific loop has no major effect on dUTPase enzymatic properties in vitro and thus a yet to be identified loop-specific function seems to be essential within the bacterial cell context. In addition, here we demonstrated that Mycob