Abstract
Phytochrom B (phyB) is a dimeric chromoprotein that detects the quantity, quality, and duration of red or far-red light throughout the entire life cycle of plants. PhyB C-terminal domain including the tandem two PAS domains (PAS1 and PAS2) was necessary for nuclear translocation and signal transduction. Here we determined the solution structures of PAS1 and PAS2 domains using multi-dimensional hetero-nuclear NMR. Loss of function missense mutants were reasonably explained based on these structures. Our structural and biochemical data revealed that the N-terminal region of the PAS1 domain was necessary to form homodimer, and the PAS1 domain did not interact with the PAS2 domain.
