4c3t

The Carbonic anhydrase from Thermovibrio ammonificans reveals an interesting intermolecular disulfide contributing to increasing thermal stability of this enzyme

spinqualitylabelsall models 4c3t, resolution 1.69Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4c3t is a 2 chain structure with sequence from Thermovibrio ammonificans. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CL, ZN Activity: Carbonate dehydratase, with EC number 4.2.1.1 Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed Carbonic anhydrase enzymes catalyse the reversible hydration of carbon dioxide to bicarbonate. A thermophilic Thermovibrio ammonificans alpha-carbonic anhydrase (TaCA) has been expressed in Escherichia coli and structurally and biochemically characterized. The crystal structure of TaCA has been determined in its native form and in two complexes with bound inhibitors. The tetrameric enzyme is stabilized by a unique core in the centre of the molecule formed by two intersubunit disulfides and a single lysine residue from each monomer that is involved in intersubunit ionic interactions. The structure of this core protects the intersubunit disulfides from reduction, whereas the conserved intrasubunit disulfides are not formed in the reducing environment of the E. coli host cytosol. When oxidized to mimic the environment of the periplasmic space, TaCA has increased thermostability, retaining 90% activity after incubation at 70 degrees C for 1 h, making it a good candidate for industrial carbon-dioxide capture. The reduction of all TaCA cysteines resulted in dissociation of the tetrameric molecule into monomers with lower activity and reduced thermostability. Unlike other characterized alpha-carbonic anhydrases, TaCA does not display esterase activity towards p-nitrophenyl acetate, which appears to result from the increased rigidity of its protein scaffold. The structure of a tetrameric alpha-carbonic anhydrase from Thermovibrio ammonificans reveals a core formed around intermolecular disulfides that contribute to its thermostability.,James P, Isupov MN, Sayer C, Saneei V, Berg S, Lioliou M, Kotlar HK, Littlechild JA Acta Crystallogr D Biol Crystallogr. 2014 Oct 1;70(Pt 10):2607-18. doi:, 10.1107/S1399004714016526. Epub 2014 Sep 27. PMID:25286845 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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