Nitric oxide adducts of the binuclear iron site of hemerythrin: spectroscopy and reactivity

Nocek, Judith M.; Kurtz, Donald M.; Sage, J. Timothy; Xia, Yao; Debrunner, Peter G.; Shiemke, Andrew K.; Sanders-Loehr, Joann; Loehr, Thomas M.

doi:10.1021/bi00403a026

Cited by 62 publications

(75 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The only other vibrational data for a biological {FeNO} 7 unit come from resonance Raman studies of the NO adduct of deoxyhemerythrin by using 647-nm excitation. Although the (N-O) stretching mode was not observed, a band at 433 cm Ϫ1 and a weak shoulder at 421 cm Ϫ1 were assigned to the (Fe-NO) and ␦(Fe-N-O) modes, respectively, of the {FeNO} 7 unit, based on 6-7 cm Ϫ1 15 NO and N 18 O downshifts (29). The frequencies of the (Fe-NO) modes dictate a substantially weaker Fe-NO bond in hemerythrin than in SOR, and this is likely to be a consequence of a strong H-bonding interaction between the bent FeNO and the -hydroxo bridge of the diiron center (29).…”

Section: Discussionmentioning

confidence: 92%

“…However, these intermediates are short lived and difficult to study experimentally. Nitric oxide (NO) has been extensively used as a substrate analog of molecular oxygen to form stable nitrosyl derivatives that provide insight into oxygen transport and activation intermediates in many heme (18)(19)(20)(21) and nonheme (22)(23)(24)(25)(26)(27)(28)(29) iron enzymes. Hence, we report here the formation and spectroscopic characterization of a stable NO-bound derivative of the reduced 1Fe-SOR from P. furiosus using the combination of EPR, UV-visible absorption, and variable-temperature, variable-field magnetic CD (VTVH MCD), resonance Raman, and Fourier transform IR (FTIR) spectroscopies.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Nitric oxide binding at the mononuclear active site of reduced Pyrococcus furiosus superoxide reductase

Clay

Cosper

Jenney

et al. 2003

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

133

View full text Add to dashboard Cite

O ver the past 4 yr, evidence has accumulated for a novel pathway for detoxification of reactive oxygen species that is specific for anaerobic and microaerophilic microorganisms (1-3). The key enzyme in this pathway is superoxide reductase (SOR), which catalyzes the reduction of superoxide to hydrogen peroxide (4), with rubredoxin as the probable physiological electron donor (2, 5). Although all SORs have a ␤-barrel domain containing a unique type of mononuclear Fe center that serves as the site for superoxide reduction (6, 7), some have an additional N-terminal domain that contains an intrinsic rubredoxin-like mononuclear Fe site, which is ligated by four cysteines in a distorted tetrahedral arrangement analogous to that found in desulforedoxin (6). These two classes are conveniently referred to as 1Fe-and 2Fe-SORs, but they are also known by their trivial names, neelaredoxins and desulfoferrodoxins, respectively.Spectroscopic and crystallographic studies of the 1Fe-SOR from Pyrococcus furiosus (7-9) and the 2Fe-SOR from Desulfovibrio desulfuricans (6, 10, 11) have shown that the mononuclear iron active site is ligated by four equatorial histidines (3 N and 1␦N) and one axial cysteinate in a square-pyramidal arrangement. The sixth coordination site appears to be occupied by a monodentate glutamate in the oxidized state but is vacant or occupied by a weakly coordinated water molecule in the reduced state, thereby providing a site for superoxide binding and reduction. These structural studies, combined with recent mutagenesis and pulse radiolysis kinetic results (12-16), have led to the proposal for the catalytic mechanism shown in Fig. 1 Characterization of enzymatic intermediates is required for both detailed understanding of the mechanism of SOR and addressing the key questions of how and why the SOR active site preferentially catalyzes reduction rather than dismutation of superoxide. However, these intermediates are short lived and difficult to study experimentally. Nitric oxide (NO) has been extensively used as a substrate analog of molecular oxygen to form stable nitrosyl derivatives that provide insight into oxygen transport and activation intermediates in many heme (18-21) and nonheme (22-29) iron enzymes. Hence, we report here the formation and spectroscopic characterization of a stable NO-bound derivative of the reduced 1Fe-SOR from P. furiosus using the combination of EPR, UV-visible absorption, and variable-temperature, variable-field magnetic CD (VTVH MCD), resonance Raman, and Fourier transform IR (FTIR) spectroscopies. The structural and electronic characterization of the NO adduct of SOR facilitates understanding of how the active site is tuned for oxidative addition of superoxide and release rather than intraligand cleavage of the peroxide product. Materials and MethodsBiochemical Techniques and Sample Preparation. Recombinant natural abundance and 34 S globally enriched P. furiosus SOR was This paper was submitted directly (Track II) to the PNAS office.Abbreviations: SOR, superoxide reductase; V...

show abstract

Section: Discussionmentioning

confidence: 92%

mentioning

confidence: 99%

Nitric oxide binding at the mononuclear active site of reduced Pyrococcus furiosus superoxide reductase

Clay

Cosper

Jenney

et al. 2003

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

133

View full text Add to dashboard Cite

show abstract

“…On a time scale basis, scavenging of R2-Y ⅐ by ⅐ NO occurred first, followed by a slower release of iron from the protein. A direct effect of ⅐ NO on the iron center of mouse R2 is unlikely, as it has been previously shown that the -oxo-bridged diferric center of hemerythrin and bacterial protein R2 do not react with NO (24,45,46). Reduction of Fe 3ϩ has been previously shown to accelerate iron loss from mouse protein R2, since Fe 2ϩ loosely binds to the protein (32).…”

Section: Discussionmentioning

confidence: 99%

Differential Sensitivity of the Tyrosyl Radical of Mouse Ribonucleotide Reductase to Nitric Oxide and Peroxynitrite

Guittet

Ducastel

Salem

et al. 1998

Journal of Biological Chemistry

View full text Add to dashboard Cite

Ribonucleotide reductase is essential for DNA synthesis in cycling cells. It has been previously shown that the catalytically competent tyrosyl free radical of its small R2 subunit (R2-Y ⅐ ) is scavenged in tumor cells co-cultured with macrophages expressing a nitric oxide synthase II activity. We now demonstrate a loss of R2-Y ⅐ induced either by ⅐ NO or peroxynitrite in vitro. The ⅐ NO effect is reversible and followed by an increase in ferric iron release from mouse protein R2. A similar increased iron lability in radical-free, diferric metR2 protein suggests reciprocal stabilizing interactions between R2-Y ⅐ and the diiron center in the mouse protein. Scavenging of R2-Y ⅐ by peroxynitrite is irreversible and paralleled to an irreversible loss of R2 activity. Formation of nitrotyrosine and dihydroxyphenylalanine was also detected in peroxynitrite-modified protein R2. In R2-overexpressing tumor cells co-cultured with activated murine macrophages, scavenging of R2-Y ⅐ following NO synthase II induction was fully reversible, even when endogenous production of peroxynitrite was induced by triggering NADPH oxidase activity with a phorbol ester. Our results did not support the involvement of peroxynitrite in R2-Y ⅐ scavenging by macrophage ⅐ NO synthase II activity. They confirmed the preponderant physiological role of ⅐ NO in the process.Nitric oxide is a cell-permeable small radical molecule synthesized in diverse organisms by NO synthase enzymes (NOS), 1 which are P450 self-sufficient hemoproteins using Larginine and dioxygen as substrates (reviewed in Ref. 1). In mammals, physiological functions have been attributed to NOS activities in cardiovascular, neural, gastrointestinal, genitourinary and immune systems (2, 3). So called "neuronal" NOS (NOS I) and "endothelial" NOS (NOS III), usually constitutively expressed, are transiently activated by elevation of intracellular Ca 2ϩ concentration (4). A cytokine-inducible NOS (NOS II) is transcriptionally regulated, producing NO at basal Ca 2ϩ levels for up to several days (4). Among cytotoxic and pathophysiological functions, NOS II was rapidly recognized to support a nonspecific antiproliferative activity capable of limiting the growth of invading agents, including viruses, bacteria, parasites, and tumor cells, consistent with the wide distribution of the isoform in different cell types (3, 4).Cytostatic antitumor effector mechanisms of macrophages have been shown to rely on induction of NOS II activity, which severely alters energy production, iron metabolism, and DNA synthesis in tumor target cells (5, 6). There is still a debate about the identity of the cytotoxic nitrogen oxide(s) acting under physiological conditions. For instance, both NO and peroxynitrite ONOO Ϫ have been reported to inhibit mitochondrial respiratory chain, and to regulate iron regulatory protein 1 function, the keystone in cell iron homeostasis (5, 7-10). Ribonucleotide reductase (RR) inhibition by a NOS II product, probably ⅐ NO, has been demonstrated in tumor cells co-cultured with macrop...

show abstract

“…In contrast, bacterial MarR family transcriptional regulators typically regulate antibiotic resistance, virulence, and oxidative stress (60). Hemerythrins are di-iron-containing proteins that can reversibly bind oxygen or nitric oxide (43). These annotations suggest that the PAE2679-PAE2680 operon encodes a transcriptional regulator that controls either stress responses or denitrification genes in response to nitric oxide.…”

Section: Fig 2 (A To E)mentioning

confidence: 99%

Transcriptional Map of Respiratory Versatility in the Hyperthermophilic Crenarchaeon Pyrobaculum aerophilum

et al. 2009

View full text Add to dashboard Cite

Hyperthermophilic crenarchaea in the genus Pyrobaculum are notable for respiratory versatility, but relatively little is known about the genetics or regulation of crenarchaeal respiratory pathways. We measured global gene expression in Pyrobaculum aerophilum cultured with oxygen, nitrate, arsenate and ferric iron as terminal electron acceptors to identify transcriptional patterns that differentiate these pathways. We also compared genome sequences for four closely related species with diverse respiratory characteristics (Pyrobaculum arsenaticum, Pyrobaculum calidifontis, Pyrobaculum islandicum, and Thermoproteus neutrophilus) to identify genes associated with different respiratory capabilities. Specific patterns of gene expression in P. aerophilum were associated with aerobic respiration, nitrate respiration, arsenate respiration, and anoxia. Functional predictions based on these patterns include separate cytochrome oxidases for aerobic growth and oxygen scavenging, a nitric oxide-responsive transcriptional regulator, a multicopper oxidase involved in denitrification, and an archaeal arsenate respiratory reductase. We were unable to identify specific genes for iron respiration, but P. aerophilum exhibited repressive transcriptional responses to iron remarkably similar to those controlled by the ferric uptake regulator in bacteria. Together, these analyses present a genome-scale view of crenarchaeal respiratory flexibility and support a large number of functional and regulatory predictions for further investigation. The complete gene expression data set can be viewed in genomic context with the Archaeal Genome Browser at archaea.ucsc.edu.With the exception of the euryarchaeal halophiles, many archaeal model organisms are either obligate aerobes (e.g., Sulfolobus spp.) or obligate anaerobes (e.g., the Thermococcales), with limited respiratory flexibility. As a consequence, relatively little is known about the genetics, regulation, and enzymology of archaeal respiratory pathways compared to those of bacteria. Species in the genus Pyrobaculum are notable both for respiratory versatility, exemplified by Pyrobaculum aerophilum, and for diversity in respiratory capabilities between closely related species (6,28,29,31,65), presenting a potential model system for investigating respiratory pathways in the crenarchaea.Pyrobaculum species grow optimally at 90 to 100°C and are common constituents of microbial communities in neutral pH geothermal springs and shallow marine hydrothermal vents (39,42,61). Pyrobaculum aerophilum is a facultative chemoautotroph that can use oxygen, nitrate, nitrite, arsenate, selenate, selenite, soluble ferric iron citrate, and insoluble ferric iron oxide as respiratory electron acceptors. The complete genome sequence of P. aerophilum was published in 2002 (23). The genome sequences of four additional Pyrobaculum species (P. arsenaticum, P. calidifontis, P. islandicum, and Thermoproteus neutrophilus [to be reclassified as a true Pyrobaculum]) have recently been completed (T. M. Lowe et al., unpub...

show abstract

Nitric oxide adducts of the binuclear iron site of hemerythrin: spectroscopy and reactivity

Cited by 62 publications

References 50 publications

Nitric oxide binding at the mononuclear active site of reduced Pyrococcus furiosus superoxide reductase

Nitric oxide binding at the mononuclear active site of reduced Pyrococcus furiosus superoxide reductase

Differential Sensitivity of the Tyrosyl Radical of Mouse Ribonucleotide Reductase to Nitric Oxide and Peroxynitrite

Transcriptional Map of Respiratory Versatility in the Hyperthermophilic Crenarchaeon Pyrobaculum aerophilum

Contact Info

Product

Resources

About