Cross-linking analysis reveals the putative dimer structure of the cyanobacterial BLUF photoreceptor PixD

FEBS Lett. 2015 Jul 8;589(15):1879-82. doi: 10.1016/j.febslet.2015.05.019. Epub 2015 May 14.

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.

Keywords: Blue light using flavin; Cyanobacteria; Photoreceptor; Phototaxis; Synechocystis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Cross-Linking Reagents / chemistry*
  • Crystallography, X-Ray
  • Cyanobacteria / chemistry*
  • Dimerization
  • Models, Molecular
  • Molecular Sequence Data
  • Photoreceptors, Microbial / chemistry*
  • Protein Conformation
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Substances

  • Cross-Linking Reagents
  • Photoreceptors, Microbial