Abstract
We have examined photoreceptor of phototaxis in thermophilic cyanobacterium Thermosynechococcus elongatus BP-1. Action spectra of the wild type cells indicated the involvement of two or more photoreceptors for the phenomenon(Kondou,et al.2001). At least one of them should be phytochrome-like protein, because of the observation of the red and far-red light reversible manner in the phototaxis.
Thus we examined the phototactic activity in disruptants of phytochrome-like genes. The action spectrum of the phototaxis in the disruptant of tlr1215 gene was measured and was compared with that in wild type. The activity of phototaxis in the disruptant of this gene decreased significantly at the red region (570nm and 640nm), indicated that the product of the tlr1215 gene was a red light receptor for phototaxis. Zinc-stain analysis of the recombinant apoprotein of Tlr1215 with biliverdin indicated that the chromophore binding occurred in vitro. Furthermore, we will discuss the role of other phytochrome-like genes.
