Thermodynamics of the As(III)−Thiol Interaction:  Arsenite and Monomethylarsenite Complexes with Glutathione, Dihydrolipoic Acid, and Other Thiol Ligands

Spuches, Anne M.; Kruszyna, Harriet; Rich, and Anne M.; Wilcox, Dean E.

doi:10.1021/ic048694q

Cited by 191 publications

(229 citation statements)

References 36 publications

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“…It is well-known that thiols reduce arsenic compounds to thiolates such as As(SR) 3 , MeAs(SR) 2 and Me 2 As(SR) [19,20,21,22], which are quantitatively converted by NaBH 4 into the corresponding hydrides [23,24]. Consequently, cold vapor generation by NaBH 4 in the presence of thiols presents an attractive way to estimate the purity of the methylarseno compounds.…”

Section: Resultsmentioning

confidence: 99%

Condensation cascades and methylgroup transfer reactions during the formation of arsane, methyl- and dimethylarsane by aqueous borohydride and (methyl) arsenates

et al. 2011

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Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Condensation cascades and methylgroup transfer reactions during the formation of arsane, methyl-and dimethylarsane by aqueous borohydride and (methyl) arsenates D'Ulivo, Alessandro; Meija, Juris; Mester, Zoltán; Pagliano, Enea; Sturgeon, Ralph E.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=fr L'accès à ce site Web et l'utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D'UTILISER CE SITE WEB. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=21268282&lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=21268282&lang=fr READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://doi.org/10.1007/s00216-011-5503-4Analytical and Bioanalytical Chemistry, 402, 2, pp. 921-933, 2011-10-30 ABSTRACTThe formation of volatile products during the reaction of As(III), As(V), MeAsO(OH) 2 and Me 2 AsO(OH) with aqueous NaBH 4 has been investigated and the formation of arsanes, di-and triarsanes has been detected . The presence of triarsanes is reported here for the first time. Di-and triarsanes are likely formed in condensation cascade reactions, whereas trimethylarsane arises via the transfer of a methyl group. The formation of volatile byproducts is considerably reduced by increasing the acidity of the medium and the concentration of NaBH 4 or by the addition of thiols, such as cysteine. A reaction scheme is proposed which reconciles the evidence reported herein and elsewhere in the literature that is valid for both analytical (trace analysis) and non-analytical reaction conditions.

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Section: Resultsmentioning

confidence: 99%

Condensation cascades and methylgroup transfer reactions during the formation of arsane, methyl- and dimethylarsane by aqueous borohydride and (methyl) arsenates

et al. 2011

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“…Although arsenic is highly toxic and a carcinogen, its interactions with biomolecules have not been thoroughly investigated. Whereas As(V) in the form of arsenate is thought to bind to phosphate-binding sites (38), As(III) is known to have high affinity for thiolate-rich sites (39). An association constant of 1 ϫ 10 7 was reported for formation of the trigonal thiolate AsL 3 complex with glutathione as measured by calorimetric and spectroscopic methods (39).…”

Section: Discussionmentioning

confidence: 99%

“…Whereas As(V) in the form of arsenate is thought to bind to phosphate-binding sites (38), As(III) is known to have high affinity for thiolate-rich sites (39). An association constant of 1 ϫ 10 7 was reported for formation of the trigonal thiolate AsL 3 complex with glutathione as measured by calorimetric and spectroscopic methods (39). We expect that the affinity of As(III) for CSL9C would be greater than or equal to that of glutathione based on our previous studies with the TRI peptides that demonstrate the effect of peptide selfassociation on the affinity of Cd(II) and Hg(II) (40).…”

Section: Discussionmentioning

confidence: 99%

Identifying important structural characteristics of arsenic resistance proteins by using designed three-stranded coiled coils

Touw

Nordman

Stuckey³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

154

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Arsenic, a contaminant of water supplies worldwide, is one of the most toxic inorganic ions. Despite arsenic's health impact, there is relatively little structural detail known about its interactions with proteins. Bacteria such as Escherichia coli have evolved arsenic resistance using the Ars operon that is regulated by ArsR, a repressor protein that dissociates from DNA when As(III) binds. This protein undergoes a critical conformational change upon binding As(III) with three cysteine residues. Unfortunately, structures of ArsR with or without As(III) have not been reported. Alternatively, de novo designed peptides can bind As(III) in an endo configuration within a thiolate-rich environment consistent with that proposed for both ArsR and ArsD. We report the structure of the As(III) complex of Coil Ser L9C to a 1.8-Å resolution, providing x-ray characterization of As(III) in a Tris thiolate protein environment and allowing a structural basis by which to understand arsenated ArsR.arsenic-binding proteins ͉ coiled coil peptides ͉ crystallography ͉ heavy metal toxicity ͉ protein design A rsenic toxicity is a worldwide problem as a natural contaminant of water supplies. Despite the fact that it is a human toxin and carcinogen, few structural reports on its interaction with biological ligands have appeared. Escherichia coli and other bacteria have evolved a detoxification mechanism that employs the arsRDABC operon (1). Arsenic removal by these encoded proteins is initiated when As(III) binds to ArsR, resulting in the dissociation of the repressor protein from the promoter DNA. The structure of the ArsA component of the ATP-dependent extrusion pump ArsAB with antimonite bound in close proximity to the nucleotide-binding site was able to provide some insight into the active transport of As(III) out of the cell (2). Additionally, structural characterization of substrate and product complexes of the arsenate reductase ArsC, which reduces arsenate (AsO 4 3Ϫ ) to arsenite (AsO 2 Ϫ ), has helped elucidate this step of the arsenic detoxification pathway (3, 4). Recent studies of E. coli ArsD indicate that it is a metallochaperone, transporting As(III) to ArsA for extrusion (5). Extended x-ray absorption fine structure and mutagenesis studies have shown that ArsR coordinates As(III) with three cysteine thiolates at a distance of 2.25 Å, a coordination mode that ArsD is also proposed to employ (1, 5). However, no x-ray or NMR structures of ArsR, the repressor protein, or ArsD have been reported to date. Furthermore, AsS 3 structures have not been reported for any biologically relevant small-molecule thiolates, such as glutathione, and only a handful of related AsS 3 complexes with aromatic ligands or chelated alkyl dithiolate coordination are reported (6).We set out to model the putative As(III) coordination environments of ArsR and ArsD in a designed peptide system. Previously, we have shown that the three-stranded coiled coildesigned with the heptad repeat strategy, such as TRI L16C (sequences of all peptides are in Table 1...

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“…Many of the effects of arsenite are attributable to its affinity for soft nucleophiles, particularly cysteine residues in glutathione and proteins (16). Arsenite rapidly oxidizes glutathione, thereby disrupting intracellular redox status (17), and forms covalent adducts with redox-sensitive protein sulfhydryls leading to protein dysfunction.…”

Section: Heme Oxygenase (Hmox)mentioning

confidence: 99%

BACH1 Is a Specific Repressor of HMOX1 That Is Inactivated by Arsenite

Reichard

Sartor

Puga

2008

Journal of Biological Chemistry

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Intracellular heme is a redox active molecule that can be detrimental to cells at high concentrations or under oxidizing conditions. To prevent accumulation, the inducible enzyme heme oxygenase-1 (HMOX1) catalyzes degradation of heme. In the absence of elevated intracellular heme or oxidative stress, the basic region leucine zipper transcriptional regulator BACH1 binds HMOX1 antioxidant response elements and represses transcription. Conversely, increased intracellular heme or sulfhydryl oxidation inactivate BACH1, permitting transcriptional induction of HMOX1. Here, we investigate the effect of BACH1 inactivation on the induction of HMOX1 and as a mechanism for broader gene induction. We show that BACH1 is inactivated at low micromolar arsenite concentrations and that BACH1 inactivation is necessary and sufficient for transcriptional induction of HMOX1. Because BACH1 is thought to interact with antioxidant response element motifs, we further examined the role of BACH1 as a regulator of inducible antioxidant gene expression by assessing the global profile of gene expression following BACH1 knockdown using small interfering RNA. The loss of BACH1 function in human keratinocytes results almost exclusively in HMOX1 induction, suggesting that BACH1 may function as a rheostat regulating levels of intracellular free heme. Heme oxygenase (HMOX)2 catalyzes the rate-limiting step of heme metabolism releasing carbon monoxide, iron, and biliverdin as products (1). Two heme oxygenase isoforms participate in heme metabolism: the inducible isoform heme oxygenase-1 (HMOX1) and the constitutive isoform heme oxygenase-2 (HMOX2). A third reported isoform, heme oxygenase-3, is considered to be a pseudogene processed from the HMOX2 transcript (2). HMOX1 induction is triggered by numerous forms of cellular stress, including transition metals (3, 4), heme and hemin (5-7), oxidants (8, 9), heat shock (10, 11), and hypoxia (12). In addition to metabolizing heme, HMOX1 reportedly protects against oxidative stress, a characteristic common to many HMOX1 inducers (13). The precise cytoprotective benefit of HMOX1 is unclear because HMOX1 itself does not directly catalyze an antioxidant reaction; however, removal of intracellular heme may be indirectly protective because (i) free intracellular heme is redox active; (ii) bilirubin, the product of biliverdin reduction, is an effective antioxidant; and (iii) iron released by heme degradation rapidly induces ferritin (14, 15).Arsenite, the trivalent form of inorganic arsenic, is an environmental contaminant of major concern and a potent inducer of oxidative stress. Many of the effects of arsenite are attributable to its affinity for soft nucleophiles, particularly cysteine residues in glutathione and proteins (16). Arsenite rapidly oxidizes glutathione, thereby disrupting intracellular redox status (17), and forms covalent adducts with redox-sensitive protein sulfhydryls leading to protein dysfunction. In response to oxidative stress, such as that mediated by arsenite, cells induce a battery of p...

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Thermodynamics of the As(III)−Thiol Interaction: Arsenite and Monomethylarsenite Complexes with Glutathione, Dihydrolipoic Acid, and Other Thiol Ligands

Cited by 191 publications

References 36 publications

Condensation cascades and methylgroup transfer reactions during the formation of arsane, methyl- and dimethylarsane by aqueous borohydride and (methyl) arsenates

Condensation cascades and methylgroup transfer reactions during the formation of arsane, methyl- and dimethylarsane by aqueous borohydride and (methyl) arsenates

Identifying important structural characteristics of arsenic resistance proteins by using designed three-stranded coiled coils

BACH1 Is a Specific Repressor of HMOX1 That Is Inactivated by Arsenite

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