Catalase-free photosystem II

The O2-evolving complex does not dismutate hydrogen peroxide

Yelena G. Sheptovitsky, Gary W Brudvig

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

A photosystem II (PSII) membrane-associated heme catalase has been identified as a major source of the dark H2O2-dismutation reaction in PSII membrane samples [Sheptovitsky, Y. G., and Brudvig, G. W. (1996) Biochemistry 35, 16255-16263]. Based on this finding, a catalase-free PSII membrane sample was prepared by using mild heat treatment to deplete most of the PSII membrane-associated heme catalase followed by inhibition of the residual catalase with 50 mM 3-amino-1,2,4-triazole, a specific heme catalase inhibitor that binds covalently to compound I. After these treatments, the PSII membrane sample exhibited only 0.02% of the original H2O2-dismutation activity when assayed in the presence of 20 mM 3-amino-1,2,4-triazole. This small residual H2O2-dismutation activity is attributed to adventitious metal ions or the non-heme iron in PSII because the activity was still present in a Mn-depleted PSII sample but was completely suppressed by adding 5 mM ferricyanide to the assay buffer; the effect of ferricyanide is attributed to oxidation of H2O2-dismutating cations. Although the H2O2- dismutation activity was completely eliminated by these treatments, the light-induced O2-evolution activity was retained. A single saturating flash given to catalase-free PSII membranes did not induce any H2O2-dismutation activity. These results demonstrate that the S1/S-1 and S2/S0 cycles of the O2-evolving complex of PSII do not occur in the presence of H2O2, as proposed by Velthuys, B., and Kok, B. [(1978) Biochim. Biophys. Acta 502, 211-221]. The light-induced O2-evolution activity in catalase-free PSH was found to be irreversibly impaired by micromolar concentrations of H2O2. Thus, it is possible that the PSII membrane-associated heme catalase plays an important role in protection of the O2-evolving complex from damage by H2O2.

Original languageEnglish
Pages (from-to)5052-5059
Number of pages8
JournalBiochemistry
Volume37
Issue number15
DOIs
Publication statusPublished - Apr 14 1998

Fingerprint

Photosystem II Protein Complex
Catalase
Hydrogen Peroxide
Membranes
Heme
Amitrole
Light
Biochemistry
Metal ions
Cations
Assays
Buffers
Iron
Hot Temperature
Metals
Heat treatment
Ions
Oxidation

ASJC Scopus subject areas

  • Biochemistry

Cite this

Catalase-free photosystem II : The O2-evolving complex does not dismutate hydrogen peroxide. / Sheptovitsky, Yelena G.; Brudvig, Gary W.

In: Biochemistry, Vol. 37, No. 15, 14.04.1998, p. 5052-5059.

Research output: Contribution to journalArticle

@article{1077a7f20d9f4710803b5b9398d936b1,
title = "Catalase-free photosystem II: The O2-evolving complex does not dismutate hydrogen peroxide",
abstract = "A photosystem II (PSII) membrane-associated heme catalase has been identified as a major source of the dark H2O2-dismutation reaction in PSII membrane samples [Sheptovitsky, Y. G., and Brudvig, G. W. (1996) Biochemistry 35, 16255-16263]. Based on this finding, a catalase-free PSII membrane sample was prepared by using mild heat treatment to deplete most of the PSII membrane-associated heme catalase followed by inhibition of the residual catalase with 50 mM 3-amino-1,2,4-triazole, a specific heme catalase inhibitor that binds covalently to compound I. After these treatments, the PSII membrane sample exhibited only 0.02{\%} of the original H2O2-dismutation activity when assayed in the presence of 20 mM 3-amino-1,2,4-triazole. This small residual H2O2-dismutation activity is attributed to adventitious metal ions or the non-heme iron in PSII because the activity was still present in a Mn-depleted PSII sample but was completely suppressed by adding 5 mM ferricyanide to the assay buffer; the effect of ferricyanide is attributed to oxidation of H2O2-dismutating cations. Although the H2O2- dismutation activity was completely eliminated by these treatments, the light-induced O2-evolution activity was retained. A single saturating flash given to catalase-free PSII membranes did not induce any H2O2-dismutation activity. These results demonstrate that the S1/S-1 and S2/S0 cycles of the O2-evolving complex of PSII do not occur in the presence of H2O2, as proposed by Velthuys, B., and Kok, B. [(1978) Biochim. Biophys. Acta 502, 211-221]. The light-induced O2-evolution activity in catalase-free PSH was found to be irreversibly impaired by micromolar concentrations of H2O2. Thus, it is possible that the PSII membrane-associated heme catalase plays an important role in protection of the O2-evolving complex from damage by H2O2.",
author = "Sheptovitsky, {Yelena G.} and Brudvig, {Gary W}",
year = "1998",
month = "4",
day = "14",
doi = "10.1021/bi972872s",
language = "English",
volume = "37",
pages = "5052--5059",
journal = "Biochemistry",
issn = "0006-2960",
publisher = "American Chemical Society",
number = "15",

}

TY - JOUR

T1 - Catalase-free photosystem II

T2 - The O2-evolving complex does not dismutate hydrogen peroxide

AU - Sheptovitsky, Yelena G.

AU - Brudvig, Gary W

PY - 1998/4/14

Y1 - 1998/4/14

N2 - A photosystem II (PSII) membrane-associated heme catalase has been identified as a major source of the dark H2O2-dismutation reaction in PSII membrane samples [Sheptovitsky, Y. G., and Brudvig, G. W. (1996) Biochemistry 35, 16255-16263]. Based on this finding, a catalase-free PSII membrane sample was prepared by using mild heat treatment to deplete most of the PSII membrane-associated heme catalase followed by inhibition of the residual catalase with 50 mM 3-amino-1,2,4-triazole, a specific heme catalase inhibitor that binds covalently to compound I. After these treatments, the PSII membrane sample exhibited only 0.02% of the original H2O2-dismutation activity when assayed in the presence of 20 mM 3-amino-1,2,4-triazole. This small residual H2O2-dismutation activity is attributed to adventitious metal ions or the non-heme iron in PSII because the activity was still present in a Mn-depleted PSII sample but was completely suppressed by adding 5 mM ferricyanide to the assay buffer; the effect of ferricyanide is attributed to oxidation of H2O2-dismutating cations. Although the H2O2- dismutation activity was completely eliminated by these treatments, the light-induced O2-evolution activity was retained. A single saturating flash given to catalase-free PSII membranes did not induce any H2O2-dismutation activity. These results demonstrate that the S1/S-1 and S2/S0 cycles of the O2-evolving complex of PSII do not occur in the presence of H2O2, as proposed by Velthuys, B., and Kok, B. [(1978) Biochim. Biophys. Acta 502, 211-221]. The light-induced O2-evolution activity in catalase-free PSH was found to be irreversibly impaired by micromolar concentrations of H2O2. Thus, it is possible that the PSII membrane-associated heme catalase plays an important role in protection of the O2-evolving complex from damage by H2O2.

AB - A photosystem II (PSII) membrane-associated heme catalase has been identified as a major source of the dark H2O2-dismutation reaction in PSII membrane samples [Sheptovitsky, Y. G., and Brudvig, G. W. (1996) Biochemistry 35, 16255-16263]. Based on this finding, a catalase-free PSII membrane sample was prepared by using mild heat treatment to deplete most of the PSII membrane-associated heme catalase followed by inhibition of the residual catalase with 50 mM 3-amino-1,2,4-triazole, a specific heme catalase inhibitor that binds covalently to compound I. After these treatments, the PSII membrane sample exhibited only 0.02% of the original H2O2-dismutation activity when assayed in the presence of 20 mM 3-amino-1,2,4-triazole. This small residual H2O2-dismutation activity is attributed to adventitious metal ions or the non-heme iron in PSII because the activity was still present in a Mn-depleted PSII sample but was completely suppressed by adding 5 mM ferricyanide to the assay buffer; the effect of ferricyanide is attributed to oxidation of H2O2-dismutating cations. Although the H2O2- dismutation activity was completely eliminated by these treatments, the light-induced O2-evolution activity was retained. A single saturating flash given to catalase-free PSII membranes did not induce any H2O2-dismutation activity. These results demonstrate that the S1/S-1 and S2/S0 cycles of the O2-evolving complex of PSII do not occur in the presence of H2O2, as proposed by Velthuys, B., and Kok, B. [(1978) Biochim. Biophys. Acta 502, 211-221]. The light-induced O2-evolution activity in catalase-free PSH was found to be irreversibly impaired by micromolar concentrations of H2O2. Thus, it is possible that the PSII membrane-associated heme catalase plays an important role in protection of the O2-evolving complex from damage by H2O2.

UR - http://www.scopus.com/inward/record.url?scp=0032515935&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0032515935&partnerID=8YFLogxK

U2 - 10.1021/bi972872s

DO - 10.1021/bi972872s

M3 - Article

VL - 37

SP - 5052

EP - 5059

JO - Biochemistry

JF - Biochemistry

SN - 0006-2960

IS - 15

ER -