Fig. 2: Cryo-EM structures of the phyB-Pfr‒PIF6β complex.
From: Structural insight into PIF6-mediated red light signal transduction of plant phytochrome B
a Domain architecture of phyB. PhyB contains the PΦB, nPAS, GAF, and PHY domains, the NTE, knot loop (KL), and hairpin (HP) loops within the PSM; the PAS1 and PAS2 domains, the modulator loop (Mod) preceding the PAS2 domain, and the DHp and CA domains within the HKRD region. The numbers represent the start and end points of the domains or loops within phyB. b Overall structure of the full-length phyB-Pfr‒PIF6β complex. Two phyB-Pfr molecules (off-white and gray) interact with one PIF6β molecule (magenta). Only PIF6N and phyB-Pfr PSMs are clearly modeled. Two phyB-Pfr PSMs are assembled in a “head-to-head” manner. PIF6N indicates N-terminus of PIF6β (residues 1‒60). c Structural overviews of the full-length phyB-Pfr‒PIF6β complex from the front (upper left), top (upper right), and side (lower left) views. The lower right shows the surface of the complex. Domains in protomer A are labeled with “(A)”, and domains in protomer B are labeled with “(B)”. The orange dashed circle represents the four-helix bundle composed of helices α1 and bundle composed of helices α6 from two phyB-Pfr protomers. d Hairpin loops (HPs) of two phyB-Pfr protomers. e Density maps of PΦB in phyB-Pfr protomer A and protomer B. PΦB adopts an “E” configuration, and it is covalently bound to residue C357.
