3m8e

Structural highlights

Function

TUBR_BACTI A DNA-binding protein that is part of the type III plasmid partition system used to ensure correct segregation of the pBtoxis plasmid. Cooperatively binds to the centromere-like site (tubC), which may seed filament formation by the TubZ polymerizing GTPase, stabilizing TubZ filaments. TubR-tubC complexes track the depolymerizing minus end of the filament, probably pulling plasmid within the cell (PubMed:20534443, PubMed:23010931, PubMed:25825718). Required for plasmid replication (PubMed:16936050, PubMed:17873046). Negatively regulates levels of TubZ; its effect on RNA expression has not been shown (Probable). Specifically binds iterons, 12-bp imperfect direct repeats that function as a plasmid origin of replication (PubMed:17873046, PubMed:23010931, PubMed:25825718). Four TubR dimers bind to tubC, forming an extended bent DNA-protein filament with protein wrapping helically around the outside of the DNA (PubMed:20534443, PubMed:23010931).^{[1] [2] [3] [4] [5] [6]}

References

1. ↑ Tang M, Bideshi DK, Park HW, Federici BA. Minireplicon from pBtoxis of Bacillus thuringiensis subsp. israelensis. Appl Environ Microbiol. 2006 Nov;72(11):6948-54. PMID:16936050 doi:10.1128/AEM.00976-06
2. ↑ Tang M, Bideshi DK, Park HW, Federici BA. Iteron-binding ORF157 and FtsZ-like ORF156 proteins encoded by pBtoxis play a role in its replication in Bacillus thuringiensis subsp. israelensis. J Bacteriol. 2007 Nov;189(22):8053-8. PMID:17873046 doi:10.1128/JB.00908-07
3. ↑ Ni L, Xu W, Kumaraswami M, Schumacher MA. Plasmid protein TubR uses a distinct mode of HTH-DNA binding and recruits the prokaryotic tubulin homolog TubZ to effect DNA partition. Proc Natl Acad Sci U S A. 2010 Jun 4. PMID:20534443
4. ↑ Aylett CH, Lowe J. Superstructure of the centromeric complex of TubZRC plasmid partitioning systems. Proc Natl Acad Sci U S A. 2012 Oct 9;109(41):16522-7. doi:, 10.1073/pnas.1210899109. Epub 2012 Sep 25. PMID:23010931 doi:http://dx.doi.org/10.1073/pnas.1210899109
5. ↑ Fink G, Löwe J. Reconstitution of a prokaryotic minus end-tracking system using TubRC centromeric complexes and tubulin-like protein TubZ filaments. Proc Natl Acad Sci U S A. 2015 Apr 14;112(15):E1845-50. PMID:25825718 doi:10.1073/pnas.1423746112
6. ↑ Larsen RA, Cusumano C, Fujioka A, Lim-Fong G, Patterson P, Pogliano J. Treadmilling of a prokaryotic tubulin-like protein, TubZ, required for plasmid stability in Bacillus thuringiensis. Genes Dev. 2007 Jun 1;21(11):1340-52. PMID:17510284 doi:10.1101/gad.1546107