کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
30968 | 44522 | 2010 | 13 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Photophysical characterisation and photo-cycle dynamics of LOV1-His domain of phototropin from Chlamydomonas reinhardtii with roseoflavin monophosphate cofactor Photophysical characterisation and photo-cycle dynamics of LOV1-His domain of phototropin from Chlamydomonas reinhardtii with roseoflavin monophosphate cofactor](/preview/png/30968.png)
The wild-type phototropin protein phot from the green alga Chlamydomonas reinhardtii with the blue-light photoreceptor domains LOV1 and LOV2 has flavin mononucleotide (FMN) as cofactor. For the LOV1-His domain from phot of C. reinhardtii studied here, the FMN chromophore was replaced by roseoflavin monophosphate (8-dimethylamino-8-demethyl-FMN, RoFMN) during heterologous expression in a riboflavin auxotropic Escherichia coli strain. An absorption and emission spectroscopic characterisation of the cofactor exchanged-LOV1-His (RoLOV1) domain was carried out in aqueous pH 8 phosphate buffer.The fluorescence of RoLOV1 is quenched by photo-induced charge transfer at room temperature. The photo-cyclic dynamics of RoLOV1 was observed by blue-light induced hypochromic and bathochromic absorption changes which recover on a minute timescale in the dark. Photo-excited RoFMN is thought to cause reversible protein and cofactor structural changes. Prolonged intense blue-light exposure caused photo-degradation of RoFMN in RoLOV1 to fully reduced flavin and lumichrome derivatives. Photo-cycle schemes of RoLOV1 and LOV1 are presented, and the photo-degradation dynamics of RoLOV1 is discussed.
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 101, Issue 1, 5 October 2010, Pages 76–88