Structure of cytochrome a3-Cua3 couple in cytochrome c oxidase as revealed by nitric oxide binding studies.

T. H. Stevens, Gary W Brudvig, D. F. Bocian, S. I. Chan

Research output: Contribution to journalArticle

95 Citations (Scopus)

Abstract

The addition of NO to oxidized cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1) causes the appearance of a high-spin heme electron paramagnetic resonance (EPR) signal due to cytochrome a3. This suggests that NO coordinates to Cu+2a3 and breaks the antiferromagnetic couple by forming a cytochrome a+33-Cu+2a3-NO complex. The intensity of the high-spin cytochrome a3 signal depends on the method of preparation of the enzyme and maximally accounts for 58% of one heme. The effect of N-3 on the cytochrome a+33-Cu+2a3-NO complex is to reduce cytochrome a3 to the ferrous state, and this is followed by formation of a new complex that exhibits EPR signals characteristic of a triplet species. On the basis of optical and EPR results, a NO bridge between cytochrome a+23 and Cu+2a3 is proposed--i.e., cytochrome a+23-NO-Cu+2a3. The half-field transition observed at g = 4.34 in the EPR spectrum of this triplet species exhibits resolved copper hyperfine splittings with [A+2] = 0.020 cm-1, indicating that the Cu+2a3 in the cytochrome a+23-NO-Cu+2a3 complex is similar to a type 2 copper site.

Original languageEnglish
Pages (from-to)3320-3324
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume76
Issue number7
Publication statusPublished - Jul 1979

Fingerprint

Cytochromes a3
Cytochromes a
Electron Spin Resonance Spectroscopy
Electron Transport Complex IV
Nitric Oxide
Heme
Copper
Enzymes

ASJC Scopus subject areas

  • General
  • Genetics

Cite this

Structure of cytochrome a3-Cua3 couple in cytochrome c oxidase as revealed by nitric oxide binding studies. / Stevens, T. H.; Brudvig, Gary W; Bocian, D. F.; Chan, S. I.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 76, No. 7, 07.1979, p. 3320-3324.

Research output: Contribution to journalArticle

@article{c2290d602c33402d92a0ded3afc04655,
title = "Structure of cytochrome a3-Cua3 couple in cytochrome c oxidase as revealed by nitric oxide binding studies.",
abstract = "The addition of NO to oxidized cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1) causes the appearance of a high-spin heme electron paramagnetic resonance (EPR) signal due to cytochrome a3. This suggests that NO coordinates to Cu+2a3 and breaks the antiferromagnetic couple by forming a cytochrome a+33-Cu+2a3-NO complex. The intensity of the high-spin cytochrome a3 signal depends on the method of preparation of the enzyme and maximally accounts for 58{\%} of one heme. The effect of N-3 on the cytochrome a+33-Cu+2a3-NO complex is to reduce cytochrome a3 to the ferrous state, and this is followed by formation of a new complex that exhibits EPR signals characteristic of a triplet species. On the basis of optical and EPR results, a NO bridge between cytochrome a+23 and Cu+2a3 is proposed--i.e., cytochrome a+23-NO-Cu+2a3. The half-field transition observed at g = 4.34 in the EPR spectrum of this triplet species exhibits resolved copper hyperfine splittings with [A+2] = 0.020 cm-1, indicating that the Cu+2a3 in the cytochrome a+23-NO-Cu+2a3 complex is similar to a type 2 copper site.",
author = "Stevens, {T. H.} and Brudvig, {Gary W} and Bocian, {D. F.} and Chan, {S. I.}",
year = "1979",
month = "7",
language = "English",
volume = "76",
pages = "3320--3324",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
number = "7",

}

TY - JOUR

T1 - Structure of cytochrome a3-Cua3 couple in cytochrome c oxidase as revealed by nitric oxide binding studies.

AU - Stevens, T. H.

AU - Brudvig, Gary W

AU - Bocian, D. F.

AU - Chan, S. I.

PY - 1979/7

Y1 - 1979/7

N2 - The addition of NO to oxidized cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1) causes the appearance of a high-spin heme electron paramagnetic resonance (EPR) signal due to cytochrome a3. This suggests that NO coordinates to Cu+2a3 and breaks the antiferromagnetic couple by forming a cytochrome a+33-Cu+2a3-NO complex. The intensity of the high-spin cytochrome a3 signal depends on the method of preparation of the enzyme and maximally accounts for 58% of one heme. The effect of N-3 on the cytochrome a+33-Cu+2a3-NO complex is to reduce cytochrome a3 to the ferrous state, and this is followed by formation of a new complex that exhibits EPR signals characteristic of a triplet species. On the basis of optical and EPR results, a NO bridge between cytochrome a+23 and Cu+2a3 is proposed--i.e., cytochrome a+23-NO-Cu+2a3. The half-field transition observed at g = 4.34 in the EPR spectrum of this triplet species exhibits resolved copper hyperfine splittings with [A+2] = 0.020 cm-1, indicating that the Cu+2a3 in the cytochrome a+23-NO-Cu+2a3 complex is similar to a type 2 copper site.

AB - The addition of NO to oxidized cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1) causes the appearance of a high-spin heme electron paramagnetic resonance (EPR) signal due to cytochrome a3. This suggests that NO coordinates to Cu+2a3 and breaks the antiferromagnetic couple by forming a cytochrome a+33-Cu+2a3-NO complex. The intensity of the high-spin cytochrome a3 signal depends on the method of preparation of the enzyme and maximally accounts for 58% of one heme. The effect of N-3 on the cytochrome a+33-Cu+2a3-NO complex is to reduce cytochrome a3 to the ferrous state, and this is followed by formation of a new complex that exhibits EPR signals characteristic of a triplet species. On the basis of optical and EPR results, a NO bridge between cytochrome a+23 and Cu+2a3 is proposed--i.e., cytochrome a+23-NO-Cu+2a3. The half-field transition observed at g = 4.34 in the EPR spectrum of this triplet species exhibits resolved copper hyperfine splittings with [A+2] = 0.020 cm-1, indicating that the Cu+2a3 in the cytochrome a+23-NO-Cu+2a3 complex is similar to a type 2 copper site.

UR - http://www.scopus.com/inward/record.url?scp=0018499136&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0018499136&partnerID=8YFLogxK

M3 - Article

C2 - 226967

AN - SCOPUS:0018499136

VL - 76

SP - 3320

EP - 3324

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

SN - 0027-8424

IS - 7

ER -