S33-02 : BLUF: the highly conserved blue-light photoreceptor controlling a wide variety of physiological activities in microorganisms
1Center for Biological Resources & Informatics, Tokyo Institute of Technology, 2Earth-Life Science Institute, Tokyo Institute of Technology
BLUF is a small (~15 kDa) flavin-binding domain that functions as a blue light-sensing module, and is widespread among the bacterial kingdom (~10% of fully sequenced bacteria). BLUF controls a wide variety of light-regulated physiological activities in several microorganisms that includes photosystem synthesis, biofilm formation, phototaxis and the photoavoidance response. Physiological analyses of several BLUF-protein mutants have indicated that the BLUF photoreceptors are important for photo-damage response under fluctuating light conditions.
The photo-activation process of BLUF is unique in that only small structural changes of the flavin are involved rather than an isomerization or covalent bond formation. Recent studies have begun to elucidate how BLUF domains transmit the light signal and identify related, subsequent changes in the domain structures. The BLUF domain structural changes could further induce conformational changes of different downstream components that include transcription factor-like proteins as well as several enzymatic domains. The mechanism of how the small flavin-binding domain can transmit the light signal to different protein modules is biochemically interest.
Here, historical backgrounds for the identification of BLUF domain, and our current understanding for mechanisms of the BLUF-dependent cell signaling will be summarized.