title: Multiple enzymatic activities of ParB/Srx superfamily mediate sexual conflict among conjugative plasmids.
abstract: Conjugative plasmids are typically locked in intergenomic and sexual conflicts with co-resident rivals, whose translocation they block using fertility inhibition factors (FINs). We describe here the first crystal structure of an enigmatic FIN Osa deployed by the proteobacterial plasmid pSa. Osa contains a catalytically active version of the ParB/Sulfiredoxin fold with both ATPase and DNase activity, the latter being regulated by an ATP-dependent switch. Using the Agrobacterium tumefaciens VirB/D4 type IV secretion system (T4SS), a relative of the conjugative T4SS, we demonstrate that catalytically active Osa blocks T-DNA transfer into plants. With a partially reconstituted T4SS in vitro, we show that Osa degrades T-DNA in the T-DNA-VirD2 complex before its translocation. Further, we present evidence for conservation and interplay between ATPase and DNase activities throughout the ParB/Sulfiredoxin fold, using other members of the family, namely P1 ParB and RK2 KorB, which have general functional implications across diverse biological contexts.
authors.affiliation: Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Priyank
authors.initials: P
authors.lastname: Maindola
authors.affiliation: Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Rahul
authors.initials: R
authors.lastname: Raina
authors.affiliation: Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Parveen
authors.initials: P
authors.lastname: Goyal
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin St, Houston, Texas 77030, USA.
authors.forename: Krishnamohan
authors.initials: K
authors.lastname: Atmakuri
authors.affiliation: Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Ojha
authors.affiliation: Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Sourabh
authors.initials: S
authors.lastname: Gupta
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin St, Houston, Texas 77030, USA.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Christie
authors.affiliation: National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, 8600 Rockville Pike, Bethesda, Maryland 20894-6075, USA.
authors.forename: Lakshminarayan M
authors.initials: LM
authors.lastname: Iyer
authors.affiliation: National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, 8600 Rockville Pike, Bethesda, Maryland 20894-6075, USA.
authors.forename: L
authors.initials: L
authors.lastname: Aravind
authors.affiliation: Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Arulandu
authors.initials: A
authors.lastname: Arockiasamy
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000378:metabolism; D003851:Deoxyribonucleases / Q000378:metabolism; D005298:Fertility; D010957:Plasmids / Q000502:physiology*; D055503:Protein Multimerization; D000069319:Type IV Secretion Systems
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; C036483:T-DNA; D000069319:Type IV Secretion Systems; D003851:Deoxyribonucleases; D000251:Adenosine Triphosphatases