The flavodiiron (Flv) proteins are present in Archaea, Bacteria and some Protozoa. Flv proteins from anaerobic organisms have been proposed to be involved in the detoxification of NO and/or O2.(1) Flv proteins have a modular structure with C-terminal flavodoxin and N-terminal metallo-β-lactamase domains as core modules. In microalgae they consist of an additional NAD(P)H:flavin oxidoreductase module that is fused at the C-terminus.1 In the cyanobacterium Synechocystis two Flv proteins Flv1 and Flv3 are essential in the light-dependent reduction of O2.(2,3) Two other Flv proteins, Flv2 and Flv4, are unique for cyanobacteria and are involved in the photoprotection of PSII under high light and CO2-limiting conditions.(4) Recent results from our lab demonstrated interplay between Flv1/Flv3 mediated photo-reduction of O2 and other important bioenergetic pathways: the photorespiratory 2-phosphoglycolate metabolism(3) and the NDH-1 complex.(4)
Phylogenetic analysis revealed two genes in the genome of Chlamydomonas reinhardtii with high homology to Synechocystis flv1 and flv3 genes.(5) As the eukaryotic green algae C. reinhardtii performs oxygenic photosynthesis similar to that in higher plants it is an interesting model organism to investigate the role of flavodiiron proteins in eukaryotic photosynthetic organisms.
This research project focuses on the analysis of the physiological functions and the mechanisms of action of the FlvA and FlvB proteins in Chlamydomonas reinhardtii by using systems biology approaches. The evolutionary aspects of flavodiiron proteins will be studied as well.