4BWI

Structure of the phytochrome Cph2 from Synechocystis sp. PCC6803

Summary for 4BWI

• Entry DOI: 10.2210/pdb4bwi/pdb
• Descriptor: PHYTOCHROME-LIKE PROTEIN CPH2, GLUTAMIC ACID, PHYCOCYANOBILIN, ... (6 entities in total)
• Functional Keywords: transferase, phycocyanobilin, pcb, red light photoreceptor
• Biological source: SYNECHOCYSTIS SP.
• Total number of polymer chains: 2
• Total formula weight: 100282.30

Authors

Anders, K.,Angerer, V.,Widany, G.D.,Mroginski, M.A.,von Stetten, D.,Essen, L.-O. (deposition date: 2013-07-03, release date: 2013-10-30, Last modification date: 2024-11-13)

Primary citation

Anders, K.,Daminelli-Widany, G.,Mroginski, M.A.,von Stetten, D.,Essen, L.-O.
Structure of the Cyanobacterial Phytochrome 2 Photosensor Implies a Tryptophan Switch for Phytochrome Signaling.
J.Biol.Chem., 288:35714-, 2013

PubMed Abstract: Phytochromes are highly versatile photoreceptors, which occur ubiquitously in plants as well as in many light-responsive microorganisms. Here, photosynthetic cyanobacteria utilize up to three different phytochrome architectures, where only the plant-like and the single-domain cyanobacteriochromes are structurally characterized so far. Cph2 represents a third group in Synechocystis species and affects their capability of phototaxis by controlling c-di-GMP synthesis and degradation. The 2.6-Å crystal structure of its red/far-red responsive photosensory module in the Pr state reveals a tandem-GAF bidomain that lacks the figure-of-eight knot of the plant/cph1 subfamily. Its covalently attached phycocyanobilin chromophore adopts a highly tilted ZZZssa conformation with a novel set of interactions between its propionates and the GAF1 domain. The tongue-like protrusion from the GAF2 domain interacts with the GAF1-bound chromophore via its conserved PRXSF, WXE, and W(G/A)G motifs. Mutagenesis showed that the integrity of the tongue is indispensable for Pr → Pfr photoconversion and involves a swap of the motifs' tryptophans within the tongue-GAF1 interface. This "Trp switch" is supposed to be a crucial element for the photochromicity of all multidomain phytochromes.

PubMed: 24174528
DOI: 10.1074/JBC.M113.510461

Experimental method

X-RAY DIFFRACTION (2.6 Å)