Oxidation of Zinc Finger Cysteines to Thiolsulfinate

Xu, Yin Feng; Wilcox, Dean E.

doi:10.1021/ja974051g

Cited by 28 publications

(26 citation statements)

References 32 publications

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“…After treatment with H 2 O 2 , DTT was able to partially (about 50%) restore the DNA complex formation of VDR/RXR (Fig. 2C) (21), or even thiosulfinate (Cys-SO-S-Cys) (52). Among the amino acids present in proteins only cysteines are modified by NO ⅐ (53), while the other reactive species used in this study are able to modify additional amino acids in proteins also, e.g.…”

Section: Discussionmentioning

confidence: 77%

Comparing Nitrosative Versus Oxidative Stress toward Zinc Finger-dependent Transcription

Kröncke¹,

Klotz

Suschek³

et al. 2002

Journal of Biological Chemistry

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Effects of nitric oxide (NO ⅐ ) on cellular functions are complex and even appear to be contradictory, janus-headed. NO ⅐ may act cytotoxically but may also protect cells from toxic insults (1), it may compromise the cellular redox state but may also act as an antioxidant (2, 3), and it may activate or inhibit signal transduction pathways (4, 5) and gene transcription (6 -9), respectively. Many of these effects can, at least in part, be explained by different NO ⅐ concentrations achieved in the respective microenvironment. Nanomolar concentrations of NO ⅐ , as typically synthesized in a tightly regulated fashion by constitutively expressed nitric oxide synthase (cNOS), 1 serve as a signal molecule activating the soluble guanylate cyclase to produce cGMP, which acts as a second messenger. However, in addition to two cNOS there is also an inducible NOS (iNOS) expressed in a variety of acute or chronic disease states (for reviews see Refs. 10, 11). Originally described as a cytotoxic activated macrophage effector molecule (12) it is now evident that iNOS-derived NO ⅐ exerts a multitude of biological functions. In an apparently unregulated fashion iNOS synthesizes NO ⅐ for hours or even days resulting in micromolar concentrations of NO ⅐ . Under these conditions NO ⅐ may react with oxygen in a reaction mainly depending on the NO ⅐ concentration to yield higher nitrogen oxides (NO x such as N 2 O 3 , etc.), which display a much broader chemical reaction spectrum than NO ⅐ itself (13). A growing body of evidence suggests that NO ⅐ after reaction to NO x helps to orchestrate gene expression, e.g. via posttranslational modifications of transcription factors. A prevalent DNA binding motif of transcription factors is the zinc finger structure with Zn 2ϩ tetrahedrally coordinated between a ␤-hairpin and a short ␣-helix, creating a small, functional and independently folded domain (14). In these zinc fingers cysteine thiols and histidine imidazole nitrogens serve as direct ligands for the zinc ion.We previously found that NO ⅐ S-nitrosates cysteines in metallothionein, mediating the release of Zn 2ϩ from this zincstoring protein (15), induces Zn 2ϩ release within cells (16) and is able to inhibit zinc finger-dependent transcription (17-19). However, zinc fingers can easily be disrupted by cysteine oxidation, e.g. by reactive oxygen species, or by electrophilic attack, e.g. by alkylating compounds (for reviews see Refs. 20,21). The question therefore arises, whether the reaction of NO ⅐ with zinc fingers may have a special role, different from the reaction with other reactive species generated during inflammatory reactions. Such species are superoxide, its dismutation product hydrogen peroxide, the product of its reaction with NO ⅐ , peroxynitrite, or singlet oxygen, as well as peroxyl radicals.To investigate the impact of these species on the zinc finger integrity, we used the transcription factors VDR and RXR as a model system both containing two Cys 4 -type zinc fingers, which bind to specific promoter sequences as the he...

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Section: Discussionmentioning

confidence: 77%

Comparing Nitrosative Versus Oxidative Stress toward Zinc Finger-dependent Transcription

Kröncke¹,

Klotz

Suschek³

et al. 2002

Journal of Biological Chemistry

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“…Xu and Wilcox reported the formation of thiosulfinates when the SP1 zinc finger was oxidised by H 2 O 2 . [7] They were proposed to come from the oxidation of disulfide by H 2 O 2 . We did not observe mass peaks corresponding to thiosulfinates in our oxidation reactions.…”

Section: Resultsmentioning

confidence: 99%

“…Comparison between the Zn 2 + -loaded and the apo form of the Sp1 transcription factor pointed to the conclusion that Zn 2 + protects the cysteines of the neutral ZnA C H T U N G T R E N N U N G (Cys) 2 A C H T U N G T R E N N U N G (His) 2 site from oxidation by O 2 and H 2 O 2 , thereby enforcing the idea that zinc-bound cysteines are poorly reactive and that zinc fingers are unreactive in comparison with free cysteines. [6,7] Recently, it was reported that zinc protects the cysteines of tris-tetraproline, a ZnA C H T U N G T R E N N U N G (Cys) 3 A C H T U N G T R E N N U N G (His) zinc finger, from oxidation, [8] but this was not evidenced for a classical ZnA C H T U N G T R E N N U N G (Cys) 2 A C H T U N G T R E N N U N G (His) 2 zinc finger. [9] However, proteins containing a reactive zinc finger site were discovered about 20 years ago.…”

Section: Introductionmentioning

confidence: 99%

Oxidation of Zn(Cys)₄ Zinc Finger Peptides by O₂ and H₂O₂: Products, Mechanism and Kinetics

Bourlès

Isaac

Lebrun

et al. 2011

Chemistry A European J

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The reactivity of a series of Zn(Cys)(4) zinc finger model peptides towards H(2)O(2) and O(2) has been investigated. The oxidation products were identified by HPLC and ESI-MS analysis. At pH<7.5, the zinc complexes and the free peptides are oxidised to bis-disulfide-containing peptides. Above pH 7.5, the oxidation of the zinc complexes by H(2)O(2) also yields sulfinate- and sulfonate-containing overoxidised peptides. At pH 7.0, monitoring of the reactions between the zinc complexes and H(2)O(2) by HPLC revealed the sequential formation of two disulfides. Several techniques for the determination of the rate constant for the first oxidation step corresponding to the attack of H(2)O(2) by the Zn(Cys)(4) site have been compared. This rate constant can be reliably determined by monitoring the oxidation by HPLC, fluorescence, circular dichroism or absorption spectroscopy in the presence of excess ethyleneglycol bis(2-aminoethyl ether)tetraacetic acid. In contrast, monitoring of the release of zinc with 4-(2-pyridylazo)resorcinol or of the thiol content with 5,5'-dithiobis(2-nitrobenzoate) did not yield reliable values of this rate constant for the case in which the formation of the second disulfide is slower than the formation of the first. The kinetic measurements clearly evidence a protective effect of zinc on the oxidation of the cysteines by both H(2)O(2) and O(2), which points to the fact that zinc binding diminishes the nucleophilicity of the thiolates. In addition, the reaction between the zinc finger and H(2)O(2) is too slow to consider zinc fingers as potential sensors for H(2)O(2) in cells.

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“…In zinc-fingers, zinc is bound to two histidine/cysteine pairs which are located at a distance of several amino-acid residues and thereby, eventhough histidine nitrogens are strong donors, there is no strong N,N 0 chelate effect to prevent zinc decoordination during the conversion of S-bonded to O-bonded sulfinates. In a paper published a few years ago [23], it has been shown that the cysteines of a peptide corresponding to a transcription factor were oxidized with H 2 O 2 in the presence of Zn(II) into thiosulfinates which are, as sulfonates, reactive sulfur oxidized species supposed to be generated under conditions of oxidative stress [24,25] Finally, we describe a very simple method to cleanly oxidize dithiolates into disulfonates under mild conditions. As a unique requirement, the thiolates have to belong to a N 2 S 2 tetradentate ligand suitable for the formation of Zn(N 2 S 2 ) complex.…”

Section: Resultsmentioning

confidence: 99%

Oxidation of Zn(N2S2) complexes to disulfonates: relevance to zinc-finger oxidation under oxidative stress

Sousa

Galardon

Rat

et al. 2005

Journal of Inorganic Biochemistry

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Oxidation of Zinc Finger Cysteines to Thiolsulfinate

Cited by 28 publications

References 32 publications

Comparing Nitrosative Versus Oxidative Stress toward Zinc Finger-dependent Transcription

Comparing Nitrosative Versus Oxidative Stress toward Zinc Finger-dependent Transcription

Oxidation of Zn(Cys)₄ Zinc Finger Peptides by O₂ and H₂O₂: Products, Mechanism and Kinetics

Oxidation of Zn(N2S2) complexes to disulfonates: relevance to zinc-finger oxidation under oxidative stress

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Oxidation of Zinc Finger Cysteines to Thiolsulfinate

Cited by 28 publications

References 32 publications

Comparing Nitrosative Versus Oxidative Stress toward Zinc Finger-dependent Transcription

Comparing Nitrosative Versus Oxidative Stress toward Zinc Finger-dependent Transcription

Oxidation of Zn(Cys)4 Zinc Finger Peptides by O2 and H2O2: Products, Mechanism and Kinetics

Oxidation of Zn(N2S2) complexes to disulfonates: relevance to zinc-finger oxidation under oxidative stress

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Oxidation of Zn(Cys)₄ Zinc Finger Peptides by O₂ and H₂O₂: Products, Mechanism and Kinetics