1. Arsenite oxidase, an ancient bioenergetic enzyme?

2. ATPase Electron transfer chain H+H+

6. Hélice transmembranaire Cluster [2Fe-2S] Domaine soluble

7. Ellis et al. 2001 Structure 9, 125-132 arsenite oxidase from Alcaligenes faecalis

8. Distribution of arsenite oxidases on the phylo tree of species

10. ssu-rRNA:

12. Chloroflexus aurantiacus - thermophilic photosynthetic bacterium (affiliated to Thermus-group) - isolated from a Yellowstone Park hot spring - earliest branching phototroph in standard ssu rRNA-trees - genome sequenced no bc-complex in Chloroflexus (genome), sole Rieske protein in the arsenite oxidase operon Inital results: - Rieske protein is membrane-associated (no RPE signal in supernatant) - Rieske protein can be light-oxidised, i.e. electrons from As III oxidation enter the photosynthetic electron transfer chain

13. ATPase Electron transfer chain H+H+

14. ATPase H+H+ Chloroflexus in the presence of arsenite h arsox AuCy mena- quinone ? As III As V photo- system + -

16. 0 100 200 Mo ? [3Fe4S] Rieske AuCy P/P + (photosystem) E m (mV) ? 300 Mo [3Fe4S] Rieske cyt c oxidase Alcaligenes faecalis As III / As V Chloroflexus aurantiacus ?

18. BIP 09/CNRS Marseile Frauke Baymann (CR1) Anne-Lise Ducluzeau (Mastère) Simon Duval (Mastère) Evelyne Lebrun (CR1) Wolfgang Nitschke (DR2) Barbara Schoepp (CR1)