PixE promotes dark oligomerization of the BLUF photoreceptor PixD.

ABSTRACT: Cyanobacteria perceive and move (phototax) in response to blue light. In this study, we demonstrate that the PixD blue light-sensing using FAD (BLUF) photoreceptor that governs this response undergoes changes in oligomerization state upon illumination. Under dark conditions we observed that PixD forms a large molecular weight complex with another protein called PixE. Stoicheometric analyses, coupled with sedimentation equilibrium and size exclusion chromatography, demonstrates that PixE drives aggregation of PixD dimers into a stable PixD(10)-PixE(5) complex under dark conditions. Illumination of a flavin chromophore in PixD destabilizes the PixD(10)-PixE(5) complex into monomers of PixE and dimers of PixD. A crystallographic structure of PixD, coupled with Gibbs free energy calculation be

SUBMITTER: Yuan H 

PROVIDER: S-EPMC2575306 | biostudies-literature | 2008 Aug

REPOSITORIES: biostudies-literature