Kinetics of conformational changes of the FKF1-LOV domain upon photoexcitation.
The photochemical reaction dynamics of a light-oxygen-voltage (LOV) domain from the blue light sensor protein, FKF1 (flavin-binding Kelch repeat F-box) was studied by means of the pulsed laser-induced transient grating method. The observed absorption spectral changes upon photoexcitation were similar to the spectral changes observed for typical LOV domain proteins (e.g., phototropins). The adduct formation took place with a time constant of 6 μs. After this reaction, a significant conformational change with a time constant of 6 ms was observed as a change in the diffusion coefficient. An FKF1-LOV mutant without the conserved loop connecting helices E and F, which is present only in the FKF1/LOV Kelch protein 2/ZEITLUPE family, did not show these slow phase dynamics. This result indicates that the conformational change in the loop region represents a major change in the FKF1-LOV photoreaction.
Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan.
Yusuke
Y
Nakasone
Kazunori
K
Zikihara
Satoru
S
Tokutomi
Masahide
M
Terazima
D000042:Absorption / Q000528:radiation effects; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000378:metabolism* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000528:radiation effects*; D002942:Circular Dichroism; D003624:Darkness; D004058:Diffusion / Q000528:radiation effects; D007700:Kinetics; D008027:Light; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000528:radiation effects; D055668:Photochemical Processes / Q000528:radiation effects; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D029681:Arabidopsis Proteins; C410504:FKF1 protein, Arabidopsis; D050505:Mutant Proteins