Involvement of cytochrome a in iron oxidation of a moderately thermophilic iron-oxidizing bacterium, strain TI-1

Masaki Takai, Kazuo Kamimura, Tsuyoshi Sugio

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The iron-oxidizing activity of a moderately thermophilic iron-oxidizing bacterium, strain TI-1, was located in the plasma membrane. When the strain was grown in Fe2+ (60 mM)-salts medium containing yeast extract (0.03%), the plasma membrane had iron-oxidizing activity of 0.129 μmol O2 uptake/mg/min. Iron oxidase was solubilized from the plasma membrane with 1.0% n-octyl-β-D-glucopyranoside (OGL) containing 25% (v/v) glycerol (pH 3.0) and purified 37-fold by a SP Sepharose FF column chromatography. Iron oxidase solubilized from the plasma membrane was stable at pH 3.0, but quite unstable in the buffer with the pH above 6.0 or below 1.0. The optimum pH and temperature for iron oxidation were 3.0 and 55°C, respectively. Solubilized enzyme from the membrane showed absorption peaks characteristic of cytochromes a and b. Cyanide and azide, inhibitors of cytochrome c oxidase, completely inhibited iron-oxidizing activity at 100 μM, but antimycin A, 2-n-heptyl-4-hydroxyquinoline-N-oxide (HOQNO) and myxothiazol, inhibitors of electron transport systems involved with cytochrome b, did not inhibit enzyme activity at 10 μM. The absorption spectrum of the most active enzyme fraction from SP Sepharose FF column chromatography (4.76 μmol O2 up take/mg/min) compared with lower active fractions from the chromatography (0.009 and 2.10 μmol O2 uptake/mg/min) showed a large α-peak of cytochrome a at 602 nm and a smaller α-peak of cytochrome b at 560 nm. The absorption spectrum of pyridine ferrohemochrome prepared from the most highly purified enzyme showed an α-peak characteristic of heme a at 587 nm, but not the α-peak characteristic of heme c at 550 nm. The cytochrome a, but not cytochrome b, in the most highly purified enzyme fraction was reduced by the addition of ferrous iron at pH 3.0, indicating that electrons from Fe2+ were transported to cytochrome a, but not cytochrome b. These results strongly suggest that cytochrome a, but not cytochromes b and c, is involved in iron oxidation of strain TI-1.

Original languageEnglish
Pages (from-to)1541-1547
Number of pages7
JournalBioscience, Biotechnology and Biochemistry
Volume63
Issue number9
Publication statusPublished - Sep 1999

Fingerprint

Cytochromes a
cytochromes
Bacteria
Cytochromes b
Iron
oxidation
iron
Proteins
Oxidation
bacteria
Cell membranes
cytochrome b
Cell Membrane
Enzymes
Chromatography
plasma membrane
Column chromatography
chromatography
Sepharose
heme

Keywords

  • Cytochrome a
  • Iron oxidase
  • Iron-oxidizing bacterium
  • Moderately thermophile

ASJC Scopus subject areas

  • Food Science
  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Biotechnology
  • Chemistry (miscellaneous)
  • Applied Microbiology and Biotechnology
  • Bioengineering

Cite this

Involvement of cytochrome a in iron oxidation of a moderately thermophilic iron-oxidizing bacterium, strain TI-1. / Takai, Masaki; Kamimura, Kazuo; Sugio, Tsuyoshi.

In: Bioscience, Biotechnology and Biochemistry, Vol. 63, No. 9, 09.1999, p. 1541-1547.

Research output: Contribution to journalArticle

@article{16e9b2a83b924729a606d6af65a63297,
title = "Involvement of cytochrome a in iron oxidation of a moderately thermophilic iron-oxidizing bacterium, strain TI-1",
abstract = "The iron-oxidizing activity of a moderately thermophilic iron-oxidizing bacterium, strain TI-1, was located in the plasma membrane. When the strain was grown in Fe2+ (60 mM)-salts medium containing yeast extract (0.03{\%}), the plasma membrane had iron-oxidizing activity of 0.129 μmol O2 uptake/mg/min. Iron oxidase was solubilized from the plasma membrane with 1.0{\%} n-octyl-β-D-glucopyranoside (OGL) containing 25{\%} (v/v) glycerol (pH 3.0) and purified 37-fold by a SP Sepharose FF column chromatography. Iron oxidase solubilized from the plasma membrane was stable at pH 3.0, but quite unstable in the buffer with the pH above 6.0 or below 1.0. The optimum pH and temperature for iron oxidation were 3.0 and 55°C, respectively. Solubilized enzyme from the membrane showed absorption peaks characteristic of cytochromes a and b. Cyanide and azide, inhibitors of cytochrome c oxidase, completely inhibited iron-oxidizing activity at 100 μM, but antimycin A, 2-n-heptyl-4-hydroxyquinoline-N-oxide (HOQNO) and myxothiazol, inhibitors of electron transport systems involved with cytochrome b, did not inhibit enzyme activity at 10 μM. The absorption spectrum of the most active enzyme fraction from SP Sepharose FF column chromatography (4.76 μmol O2 up take/mg/min) compared with lower active fractions from the chromatography (0.009 and 2.10 μmol O2 uptake/mg/min) showed a large α-peak of cytochrome a at 602 nm and a smaller α-peak of cytochrome b at 560 nm. The absorption spectrum of pyridine ferrohemochrome prepared from the most highly purified enzyme showed an α-peak characteristic of heme a at 587 nm, but not the α-peak characteristic of heme c at 550 nm. The cytochrome a, but not cytochrome b, in the most highly purified enzyme fraction was reduced by the addition of ferrous iron at pH 3.0, indicating that electrons from Fe2+ were transported to cytochrome a, but not cytochrome b. These results strongly suggest that cytochrome a, but not cytochromes b and c, is involved in iron oxidation of strain TI-1.",
keywords = "Cytochrome a, Iron oxidase, Iron-oxidizing bacterium, Moderately thermophile",
author = "Masaki Takai and Kazuo Kamimura and Tsuyoshi Sugio",
year = "1999",
month = "9",
language = "English",
volume = "63",
pages = "1541--1547",
journal = "Bioscience, Biotechnology and Biochemistry",
issn = "0916-8451",
publisher = "Japan Society for Bioscience Biotechnology and Agrochemistry",
number = "9",

}

TY - JOUR

T1 - Involvement of cytochrome a in iron oxidation of a moderately thermophilic iron-oxidizing bacterium, strain TI-1

AU - Takai, Masaki

AU - Kamimura, Kazuo

AU - Sugio, Tsuyoshi

PY - 1999/9

Y1 - 1999/9

N2 - The iron-oxidizing activity of a moderately thermophilic iron-oxidizing bacterium, strain TI-1, was located in the plasma membrane. When the strain was grown in Fe2+ (60 mM)-salts medium containing yeast extract (0.03%), the plasma membrane had iron-oxidizing activity of 0.129 μmol O2 uptake/mg/min. Iron oxidase was solubilized from the plasma membrane with 1.0% n-octyl-β-D-glucopyranoside (OGL) containing 25% (v/v) glycerol (pH 3.0) and purified 37-fold by a SP Sepharose FF column chromatography. Iron oxidase solubilized from the plasma membrane was stable at pH 3.0, but quite unstable in the buffer with the pH above 6.0 or below 1.0. The optimum pH and temperature for iron oxidation were 3.0 and 55°C, respectively. Solubilized enzyme from the membrane showed absorption peaks characteristic of cytochromes a and b. Cyanide and azide, inhibitors of cytochrome c oxidase, completely inhibited iron-oxidizing activity at 100 μM, but antimycin A, 2-n-heptyl-4-hydroxyquinoline-N-oxide (HOQNO) and myxothiazol, inhibitors of electron transport systems involved with cytochrome b, did not inhibit enzyme activity at 10 μM. The absorption spectrum of the most active enzyme fraction from SP Sepharose FF column chromatography (4.76 μmol O2 up take/mg/min) compared with lower active fractions from the chromatography (0.009 and 2.10 μmol O2 uptake/mg/min) showed a large α-peak of cytochrome a at 602 nm and a smaller α-peak of cytochrome b at 560 nm. The absorption spectrum of pyridine ferrohemochrome prepared from the most highly purified enzyme showed an α-peak characteristic of heme a at 587 nm, but not the α-peak characteristic of heme c at 550 nm. The cytochrome a, but not cytochrome b, in the most highly purified enzyme fraction was reduced by the addition of ferrous iron at pH 3.0, indicating that electrons from Fe2+ were transported to cytochrome a, but not cytochrome b. These results strongly suggest that cytochrome a, but not cytochromes b and c, is involved in iron oxidation of strain TI-1.

AB - The iron-oxidizing activity of a moderately thermophilic iron-oxidizing bacterium, strain TI-1, was located in the plasma membrane. When the strain was grown in Fe2+ (60 mM)-salts medium containing yeast extract (0.03%), the plasma membrane had iron-oxidizing activity of 0.129 μmol O2 uptake/mg/min. Iron oxidase was solubilized from the plasma membrane with 1.0% n-octyl-β-D-glucopyranoside (OGL) containing 25% (v/v) glycerol (pH 3.0) and purified 37-fold by a SP Sepharose FF column chromatography. Iron oxidase solubilized from the plasma membrane was stable at pH 3.0, but quite unstable in the buffer with the pH above 6.0 or below 1.0. The optimum pH and temperature for iron oxidation were 3.0 and 55°C, respectively. Solubilized enzyme from the membrane showed absorption peaks characteristic of cytochromes a and b. Cyanide and azide, inhibitors of cytochrome c oxidase, completely inhibited iron-oxidizing activity at 100 μM, but antimycin A, 2-n-heptyl-4-hydroxyquinoline-N-oxide (HOQNO) and myxothiazol, inhibitors of electron transport systems involved with cytochrome b, did not inhibit enzyme activity at 10 μM. The absorption spectrum of the most active enzyme fraction from SP Sepharose FF column chromatography (4.76 μmol O2 up take/mg/min) compared with lower active fractions from the chromatography (0.009 and 2.10 μmol O2 uptake/mg/min) showed a large α-peak of cytochrome a at 602 nm and a smaller α-peak of cytochrome b at 560 nm. The absorption spectrum of pyridine ferrohemochrome prepared from the most highly purified enzyme showed an α-peak characteristic of heme a at 587 nm, but not the α-peak characteristic of heme c at 550 nm. The cytochrome a, but not cytochrome b, in the most highly purified enzyme fraction was reduced by the addition of ferrous iron at pH 3.0, indicating that electrons from Fe2+ were transported to cytochrome a, but not cytochrome b. These results strongly suggest that cytochrome a, but not cytochromes b and c, is involved in iron oxidation of strain TI-1.

KW - Cytochrome a

KW - Iron oxidase

KW - Iron-oxidizing bacterium

KW - Moderately thermophile

UR - http://www.scopus.com/inward/record.url?scp=0033192245&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033192245&partnerID=8YFLogxK

M3 - Article

C2 - 10540740

AN - SCOPUS:0033192245

VL - 63

SP - 1541

EP - 1547

JO - Bioscience, Biotechnology and Biochemistry

JF - Bioscience, Biotechnology and Biochemistry

SN - 0916-8451

IS - 9

ER -