Rubredoxin from the green sulfur bacterium Chlorobium tepidum functions as an electron acceptor for pyruvate ferredoxin oxidoreductase

Ki Seok Yoon, Russ Hille, Craig Hemann, F. Robert Tabita

研究成果: ジャーナルへの寄稿記事

50 引用 (Scopus)

抄録

Rubredoxin (Rd) from the moderately thermophilic green sulfur bacterium Chlorobium tepidum was found to function as an electron acceptor for pyruvate ferredoxin oxidoreductase (PFOR). This enzyme, which catalyzes the conversion of pyruvate to acetyl-CoA and CO2, exhibited an absolute dependence upon the presence of Rd. However, Rd was incapable of participating in the pyruvate synthase or CO2 fixation reaction of C. tepidum PFOR, for which two different reduced ferredoxins are employed as electron donors. These results suggest a specific functional role for Rd in pyruvate oxidation and provide the initial indication that the two important physiological reactions catalyzed by PFOPJ pyruvate synthase are dependent on different electron carriers in the cell. The UV-visible spectrum of oxidized Rd, with a monomer molecular weight of 6500, gave a molar absorption coefficient at 492 nm of 6.89 mM-1 cm-1 with an A492/A280 ratio of 0.343 and contained one iron atom/molecule. Further spectroscopic studies indicated that the CD spectrum of oxidized C. tepidum Rd exhibited a unique absorption maximum at 385 nm and a shoulder at 420 nm. The EPR spectrum of oxidized Rd also exhibited unusual anisotropic resonances at g = 9.675 and g = 4.322, which is composed of a narrow central feature with broader shoulders to high and low field. The midpoint reduction potential of C. tepidum Rd was determined to be -87 mV, which is the most electronegative value reported for Rd from any source.

元の言語英語
ページ(範囲)29772-29778
ページ数7
ジャーナルJournal of Biological Chemistry
274
発行部数42
DOI
出版物ステータス出版済み - 10 15 1999
外部発表Yes

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Pyruvate Synthase
Chlorobium
Rubredoxins
Chlorobi
Sulfur
Bacteria
Electrons
Pyruvic Acid
Ferredoxins
Acetyl Coenzyme A
Paramagnetic resonance
Iron
Monomers
Molecular Weight
Molecular weight

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

これを引用

Rubredoxin from the green sulfur bacterium Chlorobium tepidum functions as an electron acceptor for pyruvate ferredoxin oxidoreductase. / Yoon, Ki Seok; Hille, Russ; Hemann, Craig; Tabita, F. Robert.

:: Journal of Biological Chemistry, 巻 274, 番号 42, 15.10.1999, p. 29772-29778.

研究成果: ジャーナルへの寄稿記事

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abstract = "Rubredoxin (Rd) from the moderately thermophilic green sulfur bacterium Chlorobium tepidum was found to function as an electron acceptor for pyruvate ferredoxin oxidoreductase (PFOR). This enzyme, which catalyzes the conversion of pyruvate to acetyl-CoA and CO2, exhibited an absolute dependence upon the presence of Rd. However, Rd was incapable of participating in the pyruvate synthase or CO2 fixation reaction of C. tepidum PFOR, for which two different reduced ferredoxins are employed as electron donors. These results suggest a specific functional role for Rd in pyruvate oxidation and provide the initial indication that the two important physiological reactions catalyzed by PFOPJ pyruvate synthase are dependent on different electron carriers in the cell. The UV-visible spectrum of oxidized Rd, with a monomer molecular weight of 6500, gave a molar absorption coefficient at 492 nm of 6.89 mM-1 cm-1 with an A492/A280 ratio of 0.343 and contained one iron atom/molecule. Further spectroscopic studies indicated that the CD spectrum of oxidized C. tepidum Rd exhibited a unique absorption maximum at 385 nm and a shoulder at 420 nm. The EPR spectrum of oxidized Rd also exhibited unusual anisotropic resonances at g = 9.675 and g = 4.322, which is composed of a narrow central feature with broader shoulders to high and low field. The midpoint reduction potential of C. tepidum Rd was determined to be -87 mV, which is the most electronegative value reported for Rd from any source.",
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T1 - Rubredoxin from the green sulfur bacterium Chlorobium tepidum functions as an electron acceptor for pyruvate ferredoxin oxidoreductase

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AU - Hille, Russ

AU - Hemann, Craig

AU - Tabita, F. Robert

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N2 - Rubredoxin (Rd) from the moderately thermophilic green sulfur bacterium Chlorobium tepidum was found to function as an electron acceptor for pyruvate ferredoxin oxidoreductase (PFOR). This enzyme, which catalyzes the conversion of pyruvate to acetyl-CoA and CO2, exhibited an absolute dependence upon the presence of Rd. However, Rd was incapable of participating in the pyruvate synthase or CO2 fixation reaction of C. tepidum PFOR, for which two different reduced ferredoxins are employed as electron donors. These results suggest a specific functional role for Rd in pyruvate oxidation and provide the initial indication that the two important physiological reactions catalyzed by PFOPJ pyruvate synthase are dependent on different electron carriers in the cell. The UV-visible spectrum of oxidized Rd, with a monomer molecular weight of 6500, gave a molar absorption coefficient at 492 nm of 6.89 mM-1 cm-1 with an A492/A280 ratio of 0.343 and contained one iron atom/molecule. Further spectroscopic studies indicated that the CD spectrum of oxidized C. tepidum Rd exhibited a unique absorption maximum at 385 nm and a shoulder at 420 nm. The EPR spectrum of oxidized Rd also exhibited unusual anisotropic resonances at g = 9.675 and g = 4.322, which is composed of a narrow central feature with broader shoulders to high and low field. The midpoint reduction potential of C. tepidum Rd was determined to be -87 mV, which is the most electronegative value reported for Rd from any source.

AB - Rubredoxin (Rd) from the moderately thermophilic green sulfur bacterium Chlorobium tepidum was found to function as an electron acceptor for pyruvate ferredoxin oxidoreductase (PFOR). This enzyme, which catalyzes the conversion of pyruvate to acetyl-CoA and CO2, exhibited an absolute dependence upon the presence of Rd. However, Rd was incapable of participating in the pyruvate synthase or CO2 fixation reaction of C. tepidum PFOR, for which two different reduced ferredoxins are employed as electron donors. These results suggest a specific functional role for Rd in pyruvate oxidation and provide the initial indication that the two important physiological reactions catalyzed by PFOPJ pyruvate synthase are dependent on different electron carriers in the cell. The UV-visible spectrum of oxidized Rd, with a monomer molecular weight of 6500, gave a molar absorption coefficient at 492 nm of 6.89 mM-1 cm-1 with an A492/A280 ratio of 0.343 and contained one iron atom/molecule. Further spectroscopic studies indicated that the CD spectrum of oxidized C. tepidum Rd exhibited a unique absorption maximum at 385 nm and a shoulder at 420 nm. The EPR spectrum of oxidized Rd also exhibited unusual anisotropic resonances at g = 9.675 and g = 4.322, which is composed of a narrow central feature with broader shoulders to high and low field. The midpoint reduction potential of C. tepidum Rd was determined to be -87 mV, which is the most electronegative value reported for Rd from any source.

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