The donor side of Photosystem II as the copper-inhibitory binding site
We have measured, under Cu (II) toxicity conditions, the oxygen-evolving capacity of spinach PS II particles in the Hill reactions H2O -> SiMo (in the presence and absence of DCMU) and H2O -> PPBQ, as well as the fluorescence induction curve of Tris-washed spinach PS II particles. Cu (II) inhibits both Hill reactions and, in the first case, the DCMU-insensitive H2O -> SiMo activity. In addition, the variable fluorescence is lowered by Cu (II). We have interpreted our results in terms of a donor side inhibition close to the reaction center. The same polarographic and fluorescence measurements carried out at different pHs indicate that Cu (II) could bind to amino acid residues that can be protonated and deprotonated. In order to reverse the Cu (II) inhibition by a posterior EDTA treatment, in experiments of preincubation of PS II particles with Cu (II) in light we have demonstrated that light is essential for the damage due to Cu (II) and that this furthermore is irreversible.
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1995-08
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Subjects: | Copper toxicity, Photosystem II, Spinacia oleracea, |
Online Access: | http://hdl.handle.net/10261/17225 |
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dig-irnasa-es-10261-172252016-05-24T10:05:52Z The donor side of Photosystem II as the copper-inhibitory binding site Arellano, Juan B. Lázaro, Juan J. López Gorgé, Julio Barón Ayala, Matilde Copper toxicity Photosystem II Spinacia oleracea We have measured, under Cu (II) toxicity conditions, the oxygen-evolving capacity of spinach PS II particles in the Hill reactions H2O -> SiMo (in the presence and absence of DCMU) and H2O -> PPBQ, as well as the fluorescence induction curve of Tris-washed spinach PS II particles. Cu (II) inhibits both Hill reactions and, in the first case, the DCMU-insensitive H2O -> SiMo activity. In addition, the variable fluorescence is lowered by Cu (II). We have interpreted our results in terms of a donor side inhibition close to the reaction center. The same polarographic and fluorescence measurements carried out at different pHs indicate that Cu (II) could bind to amino acid residues that can be protonated and deprotonated. In order to reverse the Cu (II) inhibition by a posterior EDTA treatment, in experiments of preincubation of PS II particles with Cu (II) in light we have demonstrated that light is essential for the damage due to Cu (II) and that this furthermore is irreversible. This work was supported by a grant from the Spanish DGICYT (PB94-0116). J.B. Arellano was the recipient of a fellowship from the Spanish Science and Education Ministry. Peer reviewed 2009-09-29T07:01:57Z 2009-09-29T07:01:57Z 1995-08 artículo http://purl.org/coar/resource_type/c_6501 Photosynthesis Research (1995) 45:127-134 http://hdl.handle.net/10261/17225 10.1007/BF00032584 en http://www.springerlink.com/content/l750136238114824/fulltext.pdf open 295011 bytes application/pdf Springer |
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Copper toxicity Photosystem II Spinacia oleracea Copper toxicity Photosystem II Spinacia oleracea Arellano, Juan B. Lázaro, Juan J. López Gorgé, Julio Barón Ayala, Matilde The donor side of Photosystem II as the copper-inhibitory binding site |
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We have measured, under Cu (II) toxicity conditions, the oxygen-evolving capacity of spinach PS II particles in the Hill reactions H2O -> SiMo (in the presence and absence of DCMU) and H2O -> PPBQ, as well as the fluorescence induction curve of Tris-washed spinach PS II particles. Cu (II) inhibits both Hill reactions and, in the first case, the DCMU-insensitive H2O -> SiMo activity. In addition, the variable fluorescence is lowered by Cu (II). We have interpreted our results in terms of a donor side inhibition close to the reaction center. The same polarographic and fluorescence measurements carried out at different pHs indicate that Cu (II) could bind to amino acid residues that can be protonated and deprotonated. In order to reverse the Cu (II) inhibition by a posterior EDTA treatment, in experiments of preincubation of PS II particles with Cu (II) in light we have demonstrated that light is essential for the damage due to Cu (II) and that this furthermore is irreversible. |
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artículo |
topic_facet |
Copper toxicity Photosystem II Spinacia oleracea |
author |
Arellano, Juan B. Lázaro, Juan J. López Gorgé, Julio Barón Ayala, Matilde |
author_facet |
Arellano, Juan B. Lázaro, Juan J. López Gorgé, Julio Barón Ayala, Matilde |
author_sort |
Arellano, Juan B. |
title |
The donor side of Photosystem II as the copper-inhibitory binding site |
title_short |
The donor side of Photosystem II as the copper-inhibitory binding site |
title_full |
The donor side of Photosystem II as the copper-inhibitory binding site |
title_fullStr |
The donor side of Photosystem II as the copper-inhibitory binding site |
title_full_unstemmed |
The donor side of Photosystem II as the copper-inhibitory binding site |
title_sort |
donor side of photosystem ii as the copper-inhibitory binding site |
publisher |
Springer |
publishDate |
1995-08 |
url |
http://hdl.handle.net/10261/17225 |
work_keys_str_mv |
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