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Oxygen-dependent copper toxicity: targets in the chlorophyll biosynthesis pathway identified in the copper efflux ATPase CopA deficient mutant

Liotenberg, Sylviane; Stenou, Anne-Soisig; Durand, Anne; Buorbon, Marie-Line; Bollivar, David; Hansson, Mats LU ; Astier, Chantal and Ouchane, Soufian (2015) In Environmental Microbiology 17. p.1963-1976
Abstract
Characterization of a copA(-) mutant in the purple photosynthetic bacterium Rubrivivax gelatinosus under low oxygen or anaerobic conditions, as well as in the human pathogen Neisseria gonorrhoeae identified HemN as a copper toxicity target enzyme in the porphyrin synthesis pathway. Heme synthesis is, however, unaffected by copper under high oxygen tension because of the aerobic coproporphyrinogen III oxidase HemF. Nevertheless, in the copA(-) mutant under aerobiosis, we show that the chlorophyll biosynthesis pathway is affected by excess copper resulting in a substantial decrease of the photosystem. Analyses of pigments and enzyme activity showed that under low copper concentrations, the mutant accumulated protochlorophyllide, suggesting... (More)
Characterization of a copA(-) mutant in the purple photosynthetic bacterium Rubrivivax gelatinosus under low oxygen or anaerobic conditions, as well as in the human pathogen Neisseria gonorrhoeae identified HemN as a copper toxicity target enzyme in the porphyrin synthesis pathway. Heme synthesis is, however, unaffected by copper under high oxygen tension because of the aerobic coproporphyrinogen III oxidase HemF. Nevertheless, in the copA(-) mutant under aerobiosis, we show that the chlorophyll biosynthesis pathway is affected by excess copper resulting in a substantial decrease of the photosystem. Analyses of pigments and enzyme activity showed that under low copper concentrations, the mutant accumulated protochlorophyllide, suggesting that the protochlorophyllide reductase activity is affected by excess copper. Increase of copper concentration led to a complete lack of chlorophyll synthesis as a result of the loss of Mg-chelatase activity. Both enzymes are widely distributed from bacteria to plants; both are [4Fe-4S] proteins and oxygen sensitive; our data demonstrate their in vivo susceptibility to copper in the presence of oxygen. Additionally, our study provides the understanding of molecular mechanisms that may contribute to chlorosis in plants when exposed to metals. The role of copper efflux systems and the impact of copper on heme and chlorophyll biosynthesis in phototrophs are addressed (Less)
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author
organization
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type
Contribution to journal
publication status
published
subject
in
Environmental Microbiology
volume
17
pages
1963 - 1976
publisher
Wiley-Blackwell
external identifiers
  • scopus:84931568026
ISSN
1462-2920
DOI
10.1111/1462-2920.12733
language
English
LU publication?
yes
id
b7da0573-3260-4e59-84ef-ad4780c0ecb2 (old id 7758747)
date added to LUP
2015-09-03 13:02:30
date last changed
2017-01-01 07:31:51
@article{b7da0573-3260-4e59-84ef-ad4780c0ecb2,
  abstract     = {Characterization of a copA(-) mutant in the purple photosynthetic bacterium Rubrivivax gelatinosus under low oxygen or anaerobic conditions, as well as in the human pathogen Neisseria gonorrhoeae identified HemN as a copper toxicity target enzyme in the porphyrin synthesis pathway. Heme synthesis is, however, unaffected by copper under high oxygen tension because of the aerobic coproporphyrinogen III oxidase HemF. Nevertheless, in the copA(-) mutant under aerobiosis, we show that the chlorophyll biosynthesis pathway is affected by excess copper resulting in a substantial decrease of the photosystem. Analyses of pigments and enzyme activity showed that under low copper concentrations, the mutant accumulated protochlorophyllide, suggesting that the protochlorophyllide reductase activity is affected by excess copper. Increase of copper concentration led to a complete lack of chlorophyll synthesis as a result of the loss of Mg-chelatase activity. Both enzymes are widely distributed from bacteria to plants; both are [4Fe-4S] proteins and oxygen sensitive; our data demonstrate their in vivo susceptibility to copper in the presence of oxygen. Additionally, our study provides the understanding of molecular mechanisms that may contribute to chlorosis in plants when exposed to metals. The role of copper efflux systems and the impact of copper on heme and chlorophyll biosynthesis in phototrophs are addressed},
  author       = {Liotenberg, Sylviane and Stenou, Anne-Soisig and Durand, Anne and Buorbon, Marie-Line and Bollivar, David and Hansson, Mats and Astier, Chantal and Ouchane, Soufian},
  issn         = {1462-2920},
  language     = {eng},
  pages        = {1963--1976},
  publisher    = {Wiley-Blackwell},
  series       = {Environmental Microbiology},
  title        = {Oxygen-dependent copper toxicity: targets in the chlorophyll biosynthesis pathway identified in the copper efflux ATPase CopA deficient mutant},
  url          = {http://dx.doi.org/10.1111/1462-2920.12733},
  volume       = {17},
  year         = {2015},
}