抄録
Phototropin (phot) is a plant blue-light receptor. Higher plants has two phot isoforms, phot1 and phot2, each of which has two chromophoric domains named LOV1 and 2 in the N-terminal half, and the C-terminal half works as a serine/threonine kinase. Photoreaction of LOV domains may alter their stracture to activate kinase. To make this clear, small-angle X-ray scattering was measured with phot1 and phot2 of Arabidopsis. Results indicates that LOV1 fragments of both phot1 and phot2 exist in a dimeric form and do not exhibit any detectable light-induced structural change. On the other hand, LOV2 is in a dimmer in phot1 and a monomer in phot2. Futhermore, LOV2 fragment of phot1 shows marked changes in scattering patterns under light illumination, indicating global structure changes during the photoreaction. These results will be discussed in connection with the different roles of LOV domains in regulating the kinase activity of phot.
