1s0y

The structure of trans-3-chloroacrylic acid dehalogenase, covalently inactivated by the mechanism-based inhibitor 3-bromopropiolate at 2.3 Angstrom resolution

spinqualitylabelsall models 1s0y, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1s0y is a 12 chain structure with sequence from Pseudomonas pavonaceae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: MLA Resources: FirstGlance, OCA, RCSB, PDBsum 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 Isomer-specific 3-chloroacrylic acid dehalogenases function in the bacterial degradation of 1,3-dichloropropene, a compound used in agriculture to kill plant-parasitic nematodes. The crystal structure of the heterohexameric trans-3-chloroacrylic acid dehalogenase (CaaD) from Pseudomonas pavonaceae 170 inactivated by 3-bromopropiolate shows that Glu-52 in the alpha-subunit is positioned to function as the water-activating base for the addition of a hydroxyl group to C-3 of 3-chloroacrylate and 3-bromopropiolate, whereas the nearby Pro-1 in the beta-subunit is positioned to provide a proton to C-2. Two arginine residues, alphaArg-8 and alphaArg-11, interact with the C-1 carboxylate groups, thereby polarizing the alpha,beta-unsaturated acids. The reaction with 3-chloroacrylate results in the production of an unstable halohydrin, 3-chloro-3-hydroxypropanoate, which decomposes into the products malonate semialdehyde and HCl. In the inactivation mechanism, however, malonyl bromide is produced, which irreversibly alkylates the betaPro-1. CaaD is related to 4-oxalocrotonate tautomerase, with which it shares an N-terminal proline. However, in 4-oxalocrotonate tautomerase, Pro-1 functions as a base participating in proton transfer within a hydrophobic active site, whereas in CaaD, the acidic proline is stabilized in a hydrophilic active site. The altered active site environment of CaaD thus facilitates a previously unknown reaction in the tautomerase superfamily, the hydration of the alpha,beta-unsaturated bonds of trans-3-chloroacrylate and 3-bromopropiolate. The mechanism for these hydration reactions represents a novel catalytic strategy that results in carbon-halogen bond cleavage. The X-ray structure of trans-3-chloroacrylic acid dehalogenase reveals a novel hydration mechanism in the tautomerase superfamily.,de Jong RM, Brugman W, Poelarends GJ, Whitman CP, Dijkstra BW J Biol Chem. 2004 Mar 19;279(12):11546-52. Epub 2003 Dec 29. PMID:14701869 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Dehalogenase

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