Temperature-sensitive reaction of a photosensor protein YcgF: possibility of a role of temperature sensor.
The spectrally silent photoreaction of a blue light sensor protein YcgF, composed of the N-terminal BLUF domain and the C-terminal EAL domain, was investigated by the time-resolved transient grating method. Comparing photoinduced reactions of full-length YcgF with that of the BLUF-linker construct, it was found that a major conformation change after photoinduced dimerization is predominantly localized on the EAL domain. Furthermore, the photoinduced conformational change displayed significant temperature dependence. This result is explained by an equilibrium of reactive and nonreactive YcgF species, with the population of photoreactive species decreasing as the temperature is lowered in the dark state. We consider that the dimer form is the nonreactive species and it is the dominant species at lower temperatures. The temperature sensitivity of the photoreaction of YcgF suggests that this protein could have a biological function as a temperature sensor as well as behaving as a light sensor.
Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
Yusuke
Y
Nakasone
Taka-aki
TA
Ono
Asako
A
Ishii
Shinji
S
Masuda
Masahide
M
Terazima
D003624:Darkness; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism*; D008027:Light; D010727:Phosphoric Diester Hydrolases / Q000737:chemistry* / Q000378:metabolism*; D055668:Photochemical Processes; D055503:Protein Multimerization / Q000528:radiation effects; D020836:Protein Structure, Quaternary; D013696:Temperature
D029968:Escherichia coli Proteins; D010727:Phosphoric Diester Hydrolases; C510176:bluF protein, E coli