A unique hetero-hexadecameric architecture displayed by the Escherichia coli O157 PaaA2–ParE2 antitoxin–toxin complex. Issue 8 (24th April 2016)

• Record Type: Journal Article
• Authors: Sterckx, Yann G.-J.; Jové, Thomas; Shkumatov, Alexander V.; Garcia-Pino, Abel; Geerts, Lieselotte; De Kerpel, Maia; Lah, Jurij; De Greve, Henri; Van Melderen, Laurence; Loris, Remy
• Is Part Of: Journal of molecular biology. Volume 428:Issue 8(2016:Apr. 15)
• Page Start: 1589
• Page End: 1603
• Publication Date: 2016-04-24
• Subjects: (TA) Toxin–antitoxin -- ITC isothermal titration calorimetry -- SEC size exclusion chromatography -- DLS dynamic light scattering -- SAXS small-angle X-ray scattering -- SPR surface plasmon resonance -- SeMet selenomethionine -- NMA normal mode analysis; RelE/ParE toxin superfamily -- protein–protein interaction -- molecular recognition -- protein structure; Molecular biology -- Periodicals; Biology -- Periodicals; Biochemistry -- Periodicals; Bacteriology -- Periodicals; Molecular Biology -- Periodicals; Biochemistry -- Periodicals; Biologie moléculaire -- Périodiques; Biologie -- Périodiques; Biochimie -- Périodiques; Moleculaire biologie; Biochemistry; Biology; Molecular biology; Periodicals; 572.805
• DOI: 10.1016/j.jmb.2016.03.007
• Languages: English
• ISSNs: 0022-2836

Abstract

Abstract : Many bacterial pathogens modulate their metabolic activity, virulence and pathogenicity through so-called "toxin–antitoxin" (TA) modules. The genome of the human pathogen Escherichia coli O157 contains two three-component TA modules related to the known parDE module. Here, we show that the toxin EcParE2 maps in a branch of the RelE/ParE toxin superfamily that is distinct from the branches that contain verified gyrase and ribosome inhibitors. The structure of EcParE2 closely resembles that of Caulobacter crescentus ParE but shows a distinct pattern of conserved surface residues, in agreement with its apparent inability to interact with GyrA. The antitoxin EcPaaA2 is characterized by two α-helices (H1 and H2) that serve as molecular recognition elements to wrap itself around EcParE2. Both EcPaaA2 H1 and H2 are required to sustain a high-affinity interaction with EcParE2 and for the inhibition of EcParE2-mediated killing in vivo . Furthermore, evidence demonstrates that EcPaaA2 H2, but not H1, determines specificity for EcParE2. The initially formed EcPaaA2–EcParE2 heterodimer then assembles into a hetero-hexadecamer, which is stable in solution and is formed in a highly cooperative manner. Together these findings provide novel data on quaternary structure, TA interactions and activity of a hitherto poorly characterized family of TA modules. Graphical abstract : Highlights : ParDE and ParDE-like TA modules remain poorly characterized. The EcPaaA2 antitoxin and EcParE2 toxin form a hetero-hexadecamer EcPaaA2 requires its two helices for EcParE2 neutralization. The second EcPaaA2 helix determines interaction specificity. EcParE2 defines a unique phylogenetic branch distinct from the ParE gyrase poisons.