title: Cross-linking analysis reveals the putative dimer structure of the cyanobacterial BLUF photoreceptor PixD.
abstract: PixD is a blue light using flavin (BLUF)-type blue-light photoreceptor controlling phototaxis in the cyanobacterium Synechocystis sp. PCC6803. The crystal structure of PixD shows a decamer, although in solution an equilibrium is maintained between the dimer and decamer. Because the ratio of these two conformers is altered by illumination, the equilibrium state determines photosensitivity. However, no structural information is available for the PixD dimer. Here, we report a predicted structure for the dimer based on docking simulation, mutagenesis, and mass spectrometry-based cross-linking analyses. The results indicate the importance of the PixD C-terminus for dimer preference and photosensitivity.
authors.affiliation: Center for Biological Resources & Informatics, Tokyo Institute of Technology, Yokohama, Japan.
authors.forename: Shukun
authors.initials: S
authors.lastname: Ren
authors.affiliation: Graduate School of Bioscience & Biotechnology, Tokyo Institute of Technology, Yokohama, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Sugimoto
authors.affiliation: Graduate School of Bioscience & Biotechnology, Tokyo Institute of Technology, Yokohama, Japan.
authors.forename: Taichi
authors.initials: T
authors.lastname: Kobayashi
authors.affiliation: Center for Biological Resources & Informatics, Tokyo Institute of Technology, Yokohama, Japan; Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan. Electronic address: shmasuda@bio.titech.ac.jp.
authors.forename: Shinji
authors.initials: S
authors.lastname: Masuda
mesh_terms: D000595:Amino Acid Sequence; D003432:Cross-Linking Reagents / Q000737:chemistry*; D018360:Crystallography, X-Ray; D000458:Cyanobacteria / Q000737:chemistry*; D019281:Dimerization; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020283:Photoreceptors, Microbial / Q000737:chemistry*; D011487:Protein Conformation; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D003432:Cross-Linking Reagents; D020283:Photoreceptors, Microbial
keywords: Blue light using flavin; Cyanobacteria; Photoreceptor; Phototaxis; Synechocystis