5hrm

<StructureSection load='5hrm' size='340' side='right' caption='[[5hrm]], [[Resolution|resolution]] 2.05&Aring;' scene=''>

<table><tr><td colspan='2'>[[5hrm]] is a 4 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5HRM OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5HRM FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=MN:MANGANESE+(II)+ION'>MN</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[5ioj|5ioj]]</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5hrm FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5hrm OCA], [http://pdbe.org/5hrm PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5hrm RCSB], [http://www.ebi.ac.uk/pdbsum/5hrm PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5hrm ProSAT]</span></td></tr>

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== Publication Abstract from PubMed ==

A novel phosphotriesterase was recently discovered and purified from Sphingobium sp. TCM1 (Sb-PTE) and shown to catalyze the hydrolysis of a broad spectrum of organophosphate esters with a catalytic efficiency that exceeds 106 M-1 s-1 for the hydrolysis of triphenyl phosphate. The enzyme was crystallized and the three-dimensional structure determined to a resolution of 2.1 A using single-wavelength anomalous diffraction (Protein Data Bank entry 5HRM ). The enzyme adopts a seven-bladed beta-propeller protein fold, and three disulfide bonds were identified between Cys-146 and Cys-242, Cys-411 and Cys-443, and Cys-542 and Cys-559. The active site of Sb-PTE contains a binuclear manganese center that is nearly identical to that of the structurally unrelated phosphotriesterase from Pseudomonas diminuta (Pd-PTE). The two metal ions in the active site are bridged to one another by Glu-201 and a water molecule. The alpha-metal ion is further coordinated to the protein by interactions with His-389, His-475, and Glu-407, whereas the beta-metal ion is further liganded to His-317 and His-258. Computational docking of mimics of the proposed pentavalent reaction intermediates for the hydrolysis of organophosphates was used to provide a model for the binding of chiral substrates in the active site of Sb-PTE. The most striking difference in the catalytic properties of Sb-PTE, relative to those of Pd-PTE, is the enhanced rate of hydrolysis of organophosphate esters with substantially weaker leaving groups. The structural basis for this difference in the catalytic properties between Sb-PTE and Pd-PTE, despite the nearly identical binuclear metal centers for the activation of the substrate and nucleophilic water molecule, is at present unclear.

 

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== References ==

[[Category: Mabanglo, M F]]

[[Category: Raushel, F M]]

[[Category: Beta-propeller]]

[[Category: Hydrolase]]

[[Category: Phosphotriesterase]]