Abstract
As for aquatic photosynthetic organisms, different sensors for photo-movement and photomorphogenesis were acquired according to each phylogenetically diversified organism. Recently, archaeal-type rhodopsin from Chlamydomonas reinhardtii and BLUF-domain-containing adenylyl cyclase from Euglena gracilis were identified as sensors of photomovement. In phototactic zoospores from brown algae, posterior flagella are green-fluorescent, which indicates the accumulation of flavin molecules. Action spectra suggested that flavoprotein in posterior flagella was a promising candidate for sensor of phototaxis. In this study, we tried to isolate and characterize the flavoprotein(s) from green-fluorescent flagella of the brown alga Scytosiphon lomentaria. Zoospores were released from the matured algal thalli. Detached flagella by Vortex treatment were frozen and suspended in Bis-Tris-propane buffer. Soluble fraction including flavoprotein was chromatographed. Fluorescence spectra and SDS-PAGE of eluates from ion-exchange and gel-filtration columns suggested that 41kDa protein was flavoprotein. Fluorescence and TLC analyses indicated that FMN was non-covalently bound to the protein.
