3m9j

Crystal structure of human thioredoxin C69/73S double mutant, reduced form

spinqualitylabelsall models 3m9j, resolution 1.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3m9j is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.1Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function THIO_HUMAN Participates in various redox reactions through the reversible oxidation of its active center dithiol to a disulfide and catalyzes dithiol-disulfide exchange reactions. Plays a role in the reversible S-nitrosylation of cysteine residues in target proteins, and thereby contributes to the response to intracellular nitric oxide. Nitrosylates the active site Cys of CASP3 in response to nitric oxide (NO), and thereby inhibits caspase-3 activity. Induces the FOS/JUN AP-1 DNA-binding activity in ionizing radiation (IR) cells through its oxidation/reduction status and stimulates AP-1 transcriptional activity. ADF augments the expression of the interleukin-2 receptor TAC (IL2R/P55). 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 Thioredoxins reduce disulfide bonds and other thiol modifications in all cells, using a CXXC motif. Human thioredoxin 1 is unusual in that it codes for an additional three cysteines in its 105 amino acid sequence, each of which have been implicated in other reductive activities. Cys 62 and Cys 69 are buried in the protein interior and lie at either end of a short helix (helix 3), and yet can disulfide link under oxidizing conditions. Cys 62 is readily S-nitrosated, giving rise to a SNO modification, which is also buried. Here, we present two crystal structures of the C69S/C73S mutant protein under oxidizing (1.5 A) and reducing (1.1 A) conditions. In the oxidized structure, helix 3 is unraveled and displays a new conformation that is stabilized by a series of new hydrogen bonds and a disulfide link with Cys 62 in a neighboring molecule. The new conformation provides an explanation for how a completely buried residue can participate in SNO exchange reactions. Crystal structure of human thioredoxin revealing an unraveled helix and exposed S- nitrosation site.,Weichsel A, Kem M, Montfort WR Protein Sci. 2010 Jul 26. PMID:20662007 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Thioredoxin 3D structures

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