[16] Protocatechuate 2,3-dioxygenase from Bacillus macerans

Wolgel, S. A.; Lipscomb, John D.

doi:10.1016/0076-6879(90)88018-6

Cited by 16 publications

(8 citation statements)

References 4 publications

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“…4 In the context of Scheme 1, the most obvious route to inactivation during turnover is loss of O 2 . (1,53). This may also be the case for the slow pNC turnover by 2,3-HPCD, but no O 2 .…”

Section: Table VII Effect Of Pnc and O 2 Addition On The Dioxygenase mentioning

confidence: 90%

Homoprotocatechuate 2,3-Dioxygenase from Brevibacterium fuscum

Miller¹,

Lipscomb²

1996

Journal of Biological Chemistry

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“…4 In the context of Scheme 1, the most obvious route to inactivation during turnover is loss of O 2 . (1,53). This may also be the case for the slow pNC turnover by 2,3-HPCD, but no O 2 .…”

Section: Table VII Effect Of Pnc and O 2 Addition On The Dioxygenase mentioning

confidence: 90%

Homoprotocatechuate 2,3-Dioxygenase from Brevibacterium fuscum

Miller¹,

Lipscomb²

1996

Journal of Biological Chemistry

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“…However, we noted that much of the expressed protein was denatured, and the small amount of folded OsARD1 contained bound Fe, as determined by atomic absorption analysis. We therefore developed a purification procedure based on that used for purifying protocatechuate 2,3‐dioxygenase from Bacillus macerans (Wolgel and Lipscomb, 1990). Frozen cell paste was thawed in four volumes (w/v) of buffer A [50 m m 3‐( N ‐morpholino)‐propanesulfonic acid (MOPS) buffer, pH 6.9, containing 100 μ m ferrous ammonium sulfate and 2 m m cysteine].…”

Section: Methodsmentioning

confidence: 99%

The immediate‐early ethylene response gene OsARD1 encodes an acireductone dioxygenase involved in recycling of the ethylene precursor S‐adenosylmethionine

Sauter

Lorbiecke

OuYang³

et al. 2005

The Plant Journal

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SummaryMethylthioadenosine (MTA) is formed as a by-product of ethylene biosynthesis from S-adenosyl-L-methionine (AdoMet). The methionine cycle regenerates AdoMet from MTA. In two independent differential screens for submergence-induced genes and for 1-aminocyclopropane-1-carboxylic acid (ACC)-induced genes from deepwater rice (Oryza sativa L.) we identified an acireductone dioxygenase (ARD). OsARD1 is a metal-binding protein that belongs to the cupin superfamily. Acireductone dioxygenases are unique proteins that can acquire two different activities depending on the metal ion bound. Ectopically expressed apo-OsARD1 preferentially binds Fe 2þ and reconstituted Fe-OsARD1 catalyzed the formation of 2-keto-pentanoate and formate from the model substrate 1,2-dihydroxy-3-ketopent-1-ene and dioxygen, indicating that OsARD1 is capable of catalyzing the penultimate step in the methionine cycle. Two highly homologous ARD genes were identified in rice.OsARD1 mRNA levels showed a rapid, early and transient increase upon submergence and after treatment with ethylene-releasing compounds. The second gene from rice, OsARD2, is constitutively expressed. Accumulation of OsARD1 transcript was observed in the same internodal tissues, i.e. the meristem and elongation zone, which were previously shown to synthesize ethylene. OsARD1 transcripts accumulated in the presence of cycloheximide, an inhibitor of protein synthesis, indicating that OsARD1 is a primary ethylene response gene. Promoter analysis suggests that immediate-early regulation of OsARD1 by ethylene may involve an EIN3-like transcription factor. OsARD1 is induced by low levels of ethylene. We propose that early feedback activation of the methionine cycle by low levels of ethylene ensures the high and continuous rates of ethylene synthesis required for longterm ethylene-mediated submergence adaptation without depleting the tissue of AdoMet.

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“…32 by growing E. coli expressing this protein in semisynthetic medium (33). The growth medium contained 54 Fe metal that had been dissolved in acid, along with a small amount of yeast extract (0.06% w/v) and ampicillin.…”

Section: Methodsmentioning

confidence: 99%

Domain Swapping in Inducible Nitric-oxide Synthase

Siddhanta¹,

Presta²,

Fan³

et al. 1998

Journal of Biological Chemistry

184

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Cytokine-inducible nitric-oxide (NO) synthase (iNOS)contains an oxygenase domain that binds heme, tetrahydrobiopterin, and L-arginine, and a reductase domain that binds FAD, FMN, calmodulin, and NADPH. Dimerization of two oxygenase domains allows electrons to transfer from the flavins to the heme irons, which enables O 2 binding and NO synthesis from L-arginine. In an iNOS heterodimer comprised of one full-length subunit and an oxygenase domain partner, the single reductase domain transfers electrons to only one of two hemes (Siddhanta, U., Wu, C., Abu-Soud, H. M., Zhang, J., Ghosh, D. K., and Stuehr, D. J. (1996) J. Biol. Chem. 271, 7309 -7312). Here, we characterize a pair of heterodimers that contain an L-Arg binding mutation (E371A) in either the full-length or oxygenase domain subunit to identify which heme iron becomes reduced. The E371A mutation prevented L-Arg binding to one oxygenase domain in each heterodimer but did not affect the L-Arg affinity of its oxygenase domain partner and did not prevent heme iron reduction in any case. The mutation prevented NO synthesis when it was located in the oxygenase domain of the adjacent subunit but had no effect when in the oxygenase domain in the same subunit as the reductase domain. Resonance Raman characterization of the heme-L-Arg interaction confirmed that E371A only prevents L-Arg binding in the mutated oxygenase domain. Thus, flavin-to-heme electron transfer proceeds exclusively between adjacent subunits in the heterodimer. This implies that domain swapping occurs in an iNOS dimer to properly align reductase and oxygenase domains for NO synthesis. Nitric oxide (NO)1 acts as a signal and cytotoxic molecule in biology (1-3) and is synthesized from L-arginine (L-Arg) by enzymes termed NO synthases (NOS). The NOS exhibit a bidomain structure in which a N-terminal oxygenase domain that contains binding sites for iron protoporphyrin IX (heme), tetrahydrobiopterin (H 4 B), and L-Arg is fused to a C-terminal reductase domain that contains binding sites for calmodulin (CaM), FMN, FAD, and NADPH (4, 5). To synthesize NO, NADPH-derived electrons must transfer from the reductase domain flavins to the oxygenase domain heme irons, which are bound to the protein via cysteine thiolate axial ligation as in the cytochromes P450 (6 -10). The flavin-to-heme electron transfer is thought to be critical for catalysis because it enables each heme iron to bind and activate oxygen at two steps in the reaction sequence, resulting in oxygen insertion into L-Arg to form N -hydroxy-L-Arg, and subsequent oxygenation to generate NO and citrulline as products (11-13).The NOS are only active as homodimers (4, 14), and understanding how dimerization relates to NOS catalysis is a topic of current interest. Studies with the cytokine-inducible NOS (iNOS) indicate its dimer assembly occurs with stable incorporation of one heme and one H 4 B into each subunit (15, 16). The dimeric interaction only requires the oxygenase domains of each subunit with the reductase domains apparently not interacting ...

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[16] Protocatechuate 2,3-dioxygenase from Bacillus macerans

Cited by 16 publications

References 4 publications

Homoprotocatechuate 2,3-Dioxygenase from Brevibacterium fuscum

Homoprotocatechuate 2,3-Dioxygenase from Brevibacterium fuscum

The immediate‐early ethylene response gene OsARD1 encodes an acireductone dioxygenase involved in recycling of the ethylene precursor S‐adenosylmethionine

Domain Swapping in Inducible Nitric-oxide Synthase

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