3f8d | pdb_00003f8d

Structure of Sulfolobus solfataricus Thioredoxin reductase Mutant C147A

spinqualitylabelsall models 3f8d, resolution 1.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3f8d is a 4 chain structure with sequence from Atcc 35091. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ACY, FAD, SO4 Related: 3f8p, 3f8r Activity: Thioredoxin-disulfide reductase, with EC number 1.8.1.9 Resources: FirstGlance, OCA, PDBe, 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 Recent investigations have demonstrated that disulfide bridges may play a crucial role in the stabilization of proteins in hyperthermophilic organisms. A major role in the process of disulfide formation is played by ubiquitous proteins belonging to the thioredoxin superfamily, which includes thioredoxins (Trx), thioredoxin reductases (TrxR), and disulfide oxidases/isomerases (PDO/PDI). Here we report a characterization of the structure and stability of the TrxR (SsTrxRB3) isolated from the archaeon Sulfolobus solfataricus. This protein is particularly interesting since it is able to process different substrates (Trxs and PDO) and it is endowed with an additional NADH oxidase activity. The crystal structure of the wild-type enzyme, of its complex with NADP and of the C147A mutant provides interesting clues on the enzyme function. In contrast to what is observed for class II TrxRs, in the structure of the oxidized enzyme, the FAD binding site is occupied by a partially disordered NAD molecule. In the active site of the C147A mutant, which exhibits a marginal NADH oxidase activity, the FAD is canonically bound to the enzyme. Molecular modeling indicates that a FAD molecule can be accommodated in the site of the reduced SsTrxRB3. Depending on the oxidation state, SsTrxRB3 can bind a different cofactor in its active site. This peculiar feature has been related to its dual activity. Denaturation experiments followed by circular dichroism indicate that electrostatic interactions play an important role in the stabilization of this thermostable protein. The analysis of the enzyme 3D-structure has also provided insights into the bases of SsTrxRB3 stability. Structure and stability of a thioredoxin reductase from Sulfolobus solfataricus: a thermostable protein with two functions.,Ruggiero A, Masullo M, Ruocco MR, Grimaldi P, Lanzotti MA, Arcari P, Zagari A, Vitagliano L Biochim Biophys Acta. 2009 Mar;1794(3):554-62. Epub 2008 Dec 6. PMID:19110078 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Thioredoxin Reductase

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