title: Light-induced structural changes of the LOV2 domains in various phototropins revealed by FTIR spectroscopy.
abstract: Phototropin (Phot), a blue-light photoreceptor in plants, consists of two FMN-binding domains (named LOV1 and LOV2) and a serine/threonine (Ser/Thr) kinase domain. We have investigated light-induced structural changes of LOV domains, which lead to the activation of the kinase domain, by means of light-induced difference FTIR spectroscopy. FTIR spectroscopy revealed that the reactive cysteine is protonated in both unphotolyzed and triplet-excited states, which is difficult to detect by other methods such as X-ray crystallography. In this review, we describe the light-induced structural changes of hydrogen-bonding environment of FMN chromophore and protein backbone inAdiantumneo1-LOV2 in the C=O stretching region by use of13C-labeled samples. We also describe the comprehensive FTIR analysis of LOV2 domains amongArabidopsisphot1, phot2, andAdiantumneo1 with and without Jα helix domain.
authors.affiliation: Center for Fostering Young and Innovative Researchers, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan; Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Iwata
authors.affiliation: Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Tokutomi
authors.affiliation: Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Kandori
keywords: FMN; FTIR spectroscopy; LOV domain; blue-light photoreceptor; phototropin