title: Coproporphyrin III excretion identifies the anaerobic coproporphyrinogen III oxidase HemN as a copper target in the Cu⁺-ATPase mutant copA⁻ of Rubrivivax gelatinosus.
abstract: Two genes encoding structurally similar Copper P1B -type ATPases can be identified in several genomes. Notwithstanding the high sequence and structural similarities these ATPases held, it has been suggested that they fulfil distinct physiological roles. In deed, we have shown that the Cu(+) -ATPase CtpA is required only for the activity of cuproproteins in the purple bacterium Rubrivivax gelatinosus; herein, we show that CopA is not directly required for cytochrome c oxidase but is vital for copper tolerance. Interestingly, excess copper in the copA(-) mutant resulted in a substantial decrease of the cytochrome c oxidase and the photosystem under microaerobic and anaerobic conditions together with the extrusion of coproporphyrin III. The data indicated that copper targeted the tetrapyrrole biosynthesis pathway at the level of the coproporphyrinogen III oxidase HemN and thereby affects the oxidase and the photosystem. This is the first in vivo demonstration that copper, like oxygen, affects tetrapyrrole biosynthesis presumably at the level of the SAM and [4Fe-4S] containing HemN enzyme. In light of these results and similar findings in Escherichia coli, the potential role of copper ions in the evolution of [4Fe-4S] enzymes and the Cu(+) -ATPases is discussed.
authors: CNRS, CGM, UPR 3404, Université Paris Sud, 1 Ave. de la Terrasse Gif sur Yvette, F-91198, France.
authors: Asma
authors: A
authors: Azzouzi
authors: Anne-Soisig
authors: AS
authors: Steunou
authors: Anne
authors: A
authors: Durand
authors: Bahia
authors: B
authors: Khalfaoui-Hassani
authors: Marie-Line
authors: ML
authors: Bourbon
authors: Chantal
authors: C
authors: Astier
authors: David W
authors: DW
authors: Bollivar
authors: Soufian
authors: S
authors: Ouchane
mesh_terms: D000693:Anaerobiosis; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D020562:Betaproteobacteria / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D003300:Copper / Q000378:metabolism* / Q000494:pharmacology; D003304:Coproporphyrinogen Oxidase / Q000235:genetics / Q000378:metabolism*; D003306:Coproporphyrins / Q000378:metabolism*; D004251:DNA Transposable Elements; D015964:Gene Expression Regulation, Bacterial; D016254:Mutagenesis, Insertional
chemical_list: D001426:Bacterial Proteins; D003300:Copper; D003304:Coproporphyrinogen Oxidase; D003306:Coproporphyrins; D004251:DNA Transposable Elements; C071263:CopA protein, Bacteria; C026971:coproporphyrin III; C109194:HemN protein, Bacteria