Quantum yield of triplet formation of riboflavin in aqueous solution and of flavin mononucleotide bound to the LOV1 domain of Photl from Chlamydomonas reinhardtii

The quantum yields of triplet formation, phi(T), of riboflavin, and of flavin mononucleotide (FMN) bound to wild-type LOV1 domain (LOV1-WT) or bound to a mutated LOV1 domain (LOV1-C57S, cysteine 57 replaced by serine) of the photo-receptor Phot1 from the green alga Chlamydomonas reinhardtii are determined by picosecond laser double-pulse excitation and time-resolved fluorescence detection. The determined quantum yields of triplet formation are phi(T) 0.375 +/- 0.05 for riboflavinin in aqueous solution at pH = 7, phi(T), = 0.225 +/- 0.04 for FMN in LOV1-C57S in aqueous solution at pH = 8, and phi(T) = 0.255 +/- 0.04 for FMN in LOV1-WT in aqueous solution at pH = 8. (C) 2003 Elsevier Science B.V. All rights reserved.