| Structural highlights
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.[1] [2] [3] [4] [5] ADF augments the expression of the interleukin-2 receptor TAC (IL2R/P55).[6] [7] [8] [9] [10]
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 are a group of ca. 12 kDa redox proteins that mediate numerous cytosolic processes in all cells. Human thioredoxin can be exported out of the cell where it has additional functions including the ability to stimulate cell growth. A recent crystal structure determination of human thioredoxin revealed an inactive dimeric form of the protein covalently linked through a disulfide bond involving Cys 73 from each monomer [Weichsel et al. (1996) Structure 4, 735-751]. In the present study, apparent dissociation constants (Kapp) for the noncovalently linked dimers were determined at various pHs using a novel assay in which preformed dimers, but not monomers, were rapidly linked through oxidation (with diamide) of the Cys 73 disulfide bond, and the relative amounts of monomer and dimer were detected by gel filtration. The values obtained were pH-dependent, varying between 6.1 and 166 microM for the pH range of 3.8-8.0, and were consistent with the titration of a single ionizable group having a pKa of 6.5. A similar value was obtained using gel filtration at pH 3.8 (Kapp = 164 microM), and the crystal structure of the diamide-oxidized protein was determined to be nearly identical to that obtained in the absence of diamide. Asp 60 lies in the dimer interface and was found to be responsible for the pH dependence for dimer formation, and therefore must have a pKa elevated by approximately 2.5 pH units. Mutation of Asp 60 to asparagine abolished nearly all of the pH dependence for dimer formation. The crystal structure of the D60N mutant revealed a dimer nearly identical to the wild type, but, surprisingly, it had the Asn 60 side chain rotated out of the dimer interface and replaced with two water molecules. The values obtained for Kapp suggest human thioredoxin may dimerize in vivo and possible roles for such dimers are discussed.
Human thioredoxin homodimers: regulation by pH, role of aspartate 60, and crystal structure of the aspartate 60 --> asparagine mutant.,Andersen JF, Sanders DA, Gasdaska JR, Weichsel A, Powis G, Montfort WR Biochemistry. 1997 Nov 18;36(46):13979-88. PMID:9369469[11]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Jacquot JP, de Lamotte F, Fontecave M, Schurmann P, Decottignies P, Miginiac-Maslow M, Wollman E. Human thioredoxin reactivity-structure/function relationship. Biochem Biophys Res Commun. 1990 Dec 31;173(3):1375-81. PMID:2176490
- ↑ Hirota K, Matsui M, Iwata S, Nishiyama A, Mori K, Yodoi J. AP-1 transcriptional activity is regulated by a direct association between thioredoxin and Ref-1. Proc Natl Acad Sci U S A. 1997 Apr 15;94(8):3633-8. PMID:9108029
- ↑ Wei SJ, Botero A, Hirota K, Bradbury CM, Markovina S, Laszlo A, Spitz DR, Goswami PC, Yodoi J, Gius D. Thioredoxin nuclear translocation and interaction with redox factor-1 activates the activator protein-1 transcription factor in response to ionizing radiation. Cancer Res. 2000 Dec 1;60(23):6688-95. PMID:11118054
- ↑ Mitchell DA, Marletta MA. Thioredoxin catalyzes the S-nitrosation of the caspase-3 active site cysteine. Nat Chem Biol. 2005 Aug;1(3):154-8. Epub 2005 Jul 10. PMID:16408020 doi:http://dx.doi.org/nchembio720
- ↑ Mitchell DA, Morton SU, Fernhoff NB, Marletta MA. Thioredoxin is required for S-nitrosation of procaspase-3 and the inhibition of apoptosis in Jurkat cells. Proc Natl Acad Sci U S A. 2007 Jul 10;104(28):11609-14. Epub 2007 Jul 2. PMID:17606900 doi:http://dx.doi.org/0704898104
- ↑ Jacquot JP, de Lamotte F, Fontecave M, Schurmann P, Decottignies P, Miginiac-Maslow M, Wollman E. Human thioredoxin reactivity-structure/function relationship. Biochem Biophys Res Commun. 1990 Dec 31;173(3):1375-81. PMID:2176490
- ↑ Hirota K, Matsui M, Iwata S, Nishiyama A, Mori K, Yodoi J. AP-1 transcriptional activity is regulated by a direct association between thioredoxin and Ref-1. Proc Natl Acad Sci U S A. 1997 Apr 15;94(8):3633-8. PMID:9108029
- ↑ Wei SJ, Botero A, Hirota K, Bradbury CM, Markovina S, Laszlo A, Spitz DR, Goswami PC, Yodoi J, Gius D. Thioredoxin nuclear translocation and interaction with redox factor-1 activates the activator protein-1 transcription factor in response to ionizing radiation. Cancer Res. 2000 Dec 1;60(23):6688-95. PMID:11118054
- ↑ Mitchell DA, Marletta MA. Thioredoxin catalyzes the S-nitrosation of the caspase-3 active site cysteine. Nat Chem Biol. 2005 Aug;1(3):154-8. Epub 2005 Jul 10. PMID:16408020 doi:http://dx.doi.org/nchembio720
- ↑ Mitchell DA, Morton SU, Fernhoff NB, Marletta MA. Thioredoxin is required for S-nitrosation of procaspase-3 and the inhibition of apoptosis in Jurkat cells. Proc Natl Acad Sci U S A. 2007 Jul 10;104(28):11609-14. Epub 2007 Jul 2. PMID:17606900 doi:http://dx.doi.org/0704898104
- ↑ Andersen JF, Sanders DA, Gasdaska JR, Weichsel A, Powis G, Montfort WR. Human thioredoxin homodimers: regulation by pH, role of aspartate 60, and crystal structure of the aspartate 60 --> asparagine mutant. Biochemistry. 1997 Nov 18;36(46):13979-88. PMID:9369469 doi:10.1021/bi971004s
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