2a5v

Crystal structure of M. tuberculosis beta carbonic anhydrase, Rv3588c, tetrameric form

spinqualitylabelsall models 2a5v, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2a5v is a 4 chain structure with sequence from Mycobacterium tuberculosis H37Rv. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.2Å Ligands: SCN, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function MTCA2_MYCTU Catalyzes the reversible hydration of carbon dioxide to form bicarbonate. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Carbonic anhydrases catalyze the reversible hydration of carbon dioxide to form bicarbonate, a reaction required for many functions, including carbon assimilation and pH homeostasis. Carbonic anhydrases are divided into at least three classes and are believed to share a zinc-hydroxide mechanism for carbon dioxide hydration. beta-carbonic anhydrases are broadly spread among the domains of life, and existing structures from different organisms show two distinct active site setups, one with three protein coordinations to the zinc (accessible) and the other with four (blocked). The latter is believed to be inconsistent with the zinc-hydroxide mechanism. The Mycobacterium tuberculosis Rv3588c gene, shown to be required for in vivo growth of the pathogen, encodes a beta-carbonic anhydrase with a steep pH dependence of its activity, being active at pH 8.4 but not at pH 7.5. We have recently solved the structure of this protein, which was a dimeric protein with a blocked active site. Here we present the structure of the thiocyanate complexed protein in a different crystal form. The protein now forms distinct tetramers and shows large structural changes, including a carboxylate shift yielding the accessible active site. This structure demonstrated for the first time that a beta-carbonic anhydrase can switch between the two states. A pH-dependent dimer to tetramer equilibrium was also demonstrated by dynamic light scattering measurements. The data presented here, therefore, suggest a carboxylate shift on/off switch for the enzyme, which may, in turn, be controlled by a dimer-to-tetramer equilibrium. Structural mechanics of the pH-dependent activity of beta-carbonic anhydrase from Mycobacterium tuberculosis.,Covarrubias AS, Bergfors T, Jones TA, Hogbom M J Biol Chem. 2006 Feb 24;281(8):4993-9. Epub 2005 Dec 1. PMID:16321983 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Carbonic anhydrase 3D structures

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