Light-induced structural changes of the LOV2 domains in various phototropins revealed by FTIR spectroscopy

Tatsuya Iwata; Satoru Tokutomi; Hideki Kandori

doi:10.2142/biophysics.7.89

Light-induced structural changes of the LOV2 domains in various phototropins revealed by FTIR spectroscopy

Biophysics (Nagoya-shi). 2011 Nov 9:7:89-98. doi: 10.2142/biophysics.7.89. eCollection 2011.

Authors

Tatsuya Iwata¹, Satoru Tokutomi², Hideki Kandori³

Affiliations

¹ 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.
² Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.
³ Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan.

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 in Adiantum neo1-LOV2 in the C=O stretching region by use of ¹³C-labeled samples. We also describe the comprehensive FTIR analysis of LOV2 domains among Arabidopsis phot1, phot2, and Adiantum neo1 with and without Jα helix domain.

Keywords: FMN; FTIR spectroscopy; LOV domain; blue-light photoreceptor; phototropin.

Publication types

Review