Photo-Cycle Dynamics of LOV1-His Domain of Phototropin from Chlamydomonas reinhardtii with Roseoflavin Monophosphate Cofactor

摘要

The wild-type phototropin protein phot from the green alga Chlamydomonas reinhardtii consists of two N-terminal LOV domains LOV1 and LOV2 with flavin mononucleotide (FMN) cofactor and a C-terminal serine-threonine kinase domain. It controls multiple steps in the sexual lifecycle of the alga. Here the LOVl-His domain of phot with modified cofactor is studied. FMN is replaced by roseoflavin monophosphate (8-dimethylamino-8-demethyl-FMN, RoFMN). The modified LOV1 domain is called RoLOVl. The photo-dynamics consequences of the cofactor change arc studied. The absorption, emission, and photo-cyclic behaviour of LOVl-His and RoLOVl-His are compared. A spectroscopic characterisation of the cofactors FMN and RoFMN (roseoflavin) is given.