4S21

Crystal structure of the photosensory core module of bacteriophytochrome RPA3015 from R. palustris

Summary for 4S21

• Entry DOI: 10.2210/pdb4s21/pdb
• Related: 4R6L 4R70
• Descriptor: Bacteriophytochrome (Light-regulated signal transduction histidine kinase), PhyB1, BILIVERDINE IX ALPHA (3 entities in total)
• Functional Keywords: pas fold, transferase, signaling protein
• Biological source: Rhodopseudomonas palustris CGA009
• Total number of polymer chains: 2
• Total formula weight: 115881.46

Authors

Yang, X.,Stojkovi, E.A.,Ozarowski, W.B.,Moffat, K. (deposition date: 2015-01-17, release date: 2015-07-15, Last modification date: 2024-10-30)

Primary citation

Yang, X.,Stojkovic, E.A.,Ozarowski, W.B.,Kuk, J.,Davydova, E.,Moffat, K.
Light Signaling Mechanism of Two Tandem Bacteriophytochromes.
Structure, 23:1179-1189, 2015

PubMed Abstract: RpBphP2 and RpBphP3, two tandem bacteriophytochromes from the photosynthetic bacterium Rhodopseudomonas palustris, share high sequence identity but exhibit distinct photoconversion behavior. Unlike the canonical RpBphP2, RpBphP3 photoconverts to an unusual near-red-absorbing (Pnr) state; both are required for synthesis of light-harvesting complexes under low-light conditions. Here we report the crystal structures of the photosensory core modules of RpBphP2 and RpBphP3. Despite different quaternary structures, RpBphP2 and RpBphP3 adopt nearly identical tertiary structures. The RpBphP3 structure reveals tongue-and-groove interactions at the interface between the GAF and PHY domains. A single mutation in the PRxSF motif at the GAF-PHY interface abolishes light-induced formation of the Pnr state in RpBphP3, possibly due to altered structural rigidity of the chromophore-binding pocket. Structural comparisons suggest that long-range signaling involves structural rearrangement of the helical spine at the dimer interface. These structures, together with mutational studies, provide insights into photoconversion and the long-range signaling mechanism in phytochromes.

PubMed: 26095026
DOI: 10.1016/j.str.2015.04.022

Experimental method

X-RAY DIFFRACTION (3.25 Å)