A Conserved Tryptophan at the Ferredoxin-Binding Site of Ferredoxin:Nitrite Oxidoreductase

Hirasawa, Masakazu; Dose, Michelle M.; Kleis-SanFrancisco, Susan; Hurley, John K.; Tollin, Gordon; Knaff, David B.

doi:10.1006/abbi.1998.0630

Cited by 9 publications

(9 citation statements)

References 26 publications

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“…It is likely that Natronomonas uses ferredoxin and not NADH as the electron donor for all three reductive conversions. This view is supported by the occurrence of conserved ferredoxinbinding residues within the N. pharaonis NirA protein (Hirasawa et al 1998) and ferredoxin dependence of nitrate and nitrite reductases in the halophile Haloferax mediterranei (MartinezEspinosa et al 2001). Nine ferredoxins of four orthologous groups (COG0633, COG1141, COG1146, COG3411) are present in N. pharaonis, and ferredoxin appears to be the common proteinaceous electron carrier for functional N-assimilation as well as the conversion of 2-oxoacids and aldehydes.…”

Section: Nitrogen Metabolismmentioning

confidence: 98%

Living with two extremes: Conclusions from the genome sequence of Natronomonas pharaonis

Pfeiffer²,

et al. 2005

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Natronomonas pharaonis is an extremely haloalkaliphilic archaeon that was isolated from salt-saturated lakes of pH 11. We sequenced its 2.6-Mb GC-rich chromosome and two plasmids (131 and 23 kb). Genome analysis suggests that it is adapted to cope with severe ammonia and heavy metal deficiencies that arise at high pH values. A high degree of nutritional self-sufficiency was predicted and confirmed by growth in a minimal medium containing leucine but no other amino acids or vitamins. Genes for a complex III analog of the respiratory chain could not be identified in the N. pharaonis genome, but respiration and oxidative phosphorylation were experimentally proven. These studies identified protons as coupling ion between respiratory chain and ATP synthase, in contrast to other alkaliphiles using sodium instead. Secretome analysis predicts many extracellular proteins with alkaline-resistant lipid anchors, which are predominantly exported through the twin-arginine pathway. In addition, a variety of glycosylated cell surface proteins probably form a protective complex cell envelope. N. pharaonis is fully equipped with archaeal signal transduction and motility genes. Several receptors/transducers signaling to the flagellar motor display novel domain architectures. Clusters of signal transduction genes are rearranged in haloarchaeal genomes, whereas those involved in information processing or energy metabolism show a highly conserved gene order.

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Section: Nitrogen Metabolismmentioning

confidence: 98%

Living with two extremes: Conclusions from the genome sequence of Natronomonas pharaonis

Pfeiffer²,

et al. 2005

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“…As was described above for spinach nitrite reductase, chemical modification studies suggested that negatively charged groups on ferredoxin (Hirasawa et al, 1986) and positively charged groups on spinach glutamate synthase (Hirasawa and Knaff, 1993) are involved in complex formation. Site-directed mutagenesis studies support the hypothesis that conserved acidic residues near the Cterminus of Fd are involved in complex formation with Fd-dependent glutamate synthase (García-Sánchez et al, 1997;Hirasawa et al, 1998;García-Sánchez et al, 2000). The mutational studies involving C. reinhardtii Fd have provided evidence that a second acidic region on Fd, containing Asp25, Glu28, and Glu29, also plays a role in binding glutamate synthase (García-Sánchez et al, 2000).…”

Section: B Ferredoxin-dependent Glutamate Synthasementioning

confidence: 78%

“…In photosynthetic eukaryotes, the genes encoding the enzymes are located in the nucleus and the proteins are synthesized in the cytoplasm as precursor proteins, with an N-terminal signal sequence that targets them for delivery to the chloroplast stroma, which is subsequently cleaved to form the mature-length protein (Back et al, 1988). Amino acid sequences, usually deduced from the corresponding cDNA sequences (including one for the 62,883 Da spinach enzyme), are available and the proteins, regardless of whether they are from cyanobacteria, algae, or higher plants, show significant regions of homology (Back et al, 1988;Luque et al, 1993;Bellissimo and Privalle, 1995;Knaff, 1996;Dose et al, 1997;Hirasawa et al, 1998). The enzymes contain one noncovalently bound siroheme and one low-potential [4Fe-4S] +1,+2 cluster as the only prosthetic groups, with nitrite binding occurring at the siroheme iron through the N atom of the substrate (Knaff, 1996;Kuznetsova et al, 2004a,b).…”

Section: Nitrite Reductasementioning

confidence: 98%

The Interaction of Ferredoxin with Ferredoxin-Dependent Enzymes

Hase

Schürmann

Knaff

Advances in Photosynthesis and Respiration

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“…Protein concentrations (Hirasawa and Knaff 1985;Hirasawa et al 2004) and enzymatic activities (Akashi et al 1999;YonekuraSakakibara et al 2000) were estimated as described previously. Modifications of the wild-type sulfite reductase with N-acetylsuccinimide, with phenylglyoxal and with N-bromosuccinimide (hereafter abbreviated as NBS), were carried out as described previously for nitrite reductase and glutamate synthase (Hirasawa and Knaff 1993a, b;Hirasawa et al 1994Hirasawa et al , 1998a. The ratios of chemical modifier to enzyme used were chosen, after different ranges of stoichiometries were tested, to provide the maximum affect on enzymatic activity combined with minimal levels of changes in absorbance and CD spectra and oxidationreduction midpoint potential.…”

Section: Methodsmentioning

confidence: 99%

“…In the case of these other ferredoxin-dependent enzymes, arginine and lysine residues on the enzymes have been implicated in ferredoxin binding (Hase et al 2005). There is also evidence, from chemical modification studies, that at least one tryptophan residue may be present at or near the ferredoxinbinding site of both nitrite reductase (Hirasawa et al, 1994(Hirasawa et al, , 1998aDose et al 1997) and glutamate synthase (Hirasawa et al 1998b). Ferredoxin-dependent sulfite reductases have a number of well-conserved arginine, lysine and tryptophan residues ( Figure 1).…”

Section: Introductionmentioning

confidence: 95%

Chemical modification studies of tryptophan, arginine and lysine residues in maize chloroplast ferredoxin:sulfite oxidoreductase

et al. 2005

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The ferredoxin-dependent sulfite reductase from maize was treated, in separate experiments, with three different covalent modifiers of specific amino acid side chains. Treatment with the tryptophan-modifying reagent, N-bromosuccinimide (NBS), resulted in a loss of enzymatic activity with both the physiological donor for the enzyme, reduced ferredoxin, and with reduced methyl viologen, a non-physiological electron donor. Formation of the 1:1 ferredoxin/sulfite reductase complex prior to treating the enzyme with NBS completely protected the enzyme against the loss of both activities. Neither the secondary structure, nor the oxidation-reduction midpoint potential (Em) values of the siroheme and [4Fe-4S] cluster prosthetic groups of sulfite reductase, nor the binding affinity of the enzyme for ferredoxin were affected by NBS treatment. Treatment of sulfite reductase with the lysine-modifying reagent, N-acetylsuccinimide, inhibited the ferredoxin-linked activity of the enzyme without inhibiting the methyl viologen-linked activity. Complex formation with ferredoxin protects the enzyme against the inhibition of ferredoxin-linked activity produced by treatment with N-acetylsuccinimide. Treatment of sulfite reductase with N-acetylsuccinimide also decreased the binding affinity of the enzyme for ferredoxin. Treatment of sulfite reductase with the arginine-modifying reagent, phenylglyoxal, inhibited both the ferredoxin-linked and methyl viologen-linked activities of the enzyme but had a significantly greater effect on the ferredoxin-dependent activity than on the reduced methyl viologen-linked activity. The effects of these three inhibitory treatments are consistent with a possible role for a tryptophan residue the catalytic mechanism of sulfite reductase and for lysine and arginine residues at the ferredoxin-binding site of the enzyme.

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A Conserved Tryptophan at the Ferredoxin-Binding Site of Ferredoxin:Nitrite Oxidoreductase

Cited by 9 publications

References 26 publications

Living with two extremes: Conclusions from the genome sequence of Natronomonas pharaonis

Living with two extremes: Conclusions from the genome sequence of Natronomonas pharaonis

The Interaction of Ferredoxin with Ferredoxin-Dependent Enzymes

Chemical modification studies of tryptophan, arginine and lysine residues in maize chloroplast ferredoxin:sulfite oxidoreductase

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