1ur5

Stabilization of a Tetrameric Malate Dehydrogenase by Introduction of a Disulfide Bridge at the Dimer/Dimer Interface

spinqualitylabelsall models 1ur5, resolution 1.75Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1ur5 is a 2 chain structure with sequence from Chloroflexus aurantiacus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.75Å Ligands: CD, CL, NA, NAD Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function MDH_CHLAA Catalyzes the reversible oxidation of malate to oxaloacetate.[HAMAP-Rule:MF_00487] 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 Malate dehydrogenase (MDH) from the moderately thermophilic bacterium Chloroflexus aurantiacus (CaMDH) is a tetrameric enzyme, while MDHs from mesophilic organisms usually are dimers. To investigate the potential contribution of the extra dimer-dimer interface in CaMDH with respect to thermal stability, we have engineered an intersubunit disulfide bridge designed to strengthen dimer-dimer interactions. The resulting mutant (T187C, containing two 187-187 disulfide bridges in the tetramer) showed a 200-fold increase in half-life at 75 degrees C and an increase of 15 deg. C in apparent melting temperature compared to the wild-type. The crystal structure of the mutant (solved at 1.75 A resolution) was essentially identical with that of the wild-type, with the exception of the added inter-dimer disulfide bridge and the loss of an aromatic intra-dimer contact. Remarkably, the mutant and the wild-type had similar temperature optima and activities at their temperature optima, thus providing a clear case of uncoupling of thermal stability and thermoactivity. The results show that tetramerization may contribute to MDH stability to an extent that depends strongly on the number of stabilizing interactions in the dimer-dimer interface. Stabilization of a tetrameric malate dehydrogenase by introduction of a disulfide bridge at the dimer-dimer interface.,Bjork A, Dalhus B, Mantzilas D, Eijsink VG, Sirevag R J Mol Biol. 2003 Dec 5;334(4):811-21. PMID:14636605 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Malate Dehydrogenase 3D structures

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