9jry

Crystal structure of FiDCB, a dual-cysteine cyanobacterial phytochrome of Fischerella sp. PCC 9605

spinqualitylabelsall models 9jry, resolution 3.35Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9jry is a 2 chain structure with sequence from Fischerella sp. PCC 9605. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.35Å Ligands: BLR Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Previous studies have identified three families of knotted phytochrome photoreceptors in cyanobacteria. We describe a fourth type: 'hybrid' phytochromes with putative bilin-binding cysteine residues in both their N-terminal 'knot' extensions and cGMP-phosphodiesterase/adenylate cyclase/FhlA (GAF) domains, which we designate as dual-cysteine bacteriophytochromes (DCBs). Recombinant expression of DCBs in Escherichia coli yields photoactive phycocyanobilin (PCB) adducts with red/far-red photocycles similar to those of the GAF-Cys-containing cyanobacterial phytochromes (Cph1s). Incorporation of the PCB precursor, biliverdin IXalpha (BV), gave multiple populations, one of which appears similar to those of cyanobacterial bacteriophytochromes (cBphPs). A crystal structure of FiDCB bound to BV exhibits two thioether linkages between the GAF- and 'PAS-knot'-Cys residues and the C3(1) and C3(2) atoms of BV. When expressed in Synechocystis sp. PCC 6803, DCBs incorporate PCB rather than BV. DCBs can be converted to photoactive cBphP-, Cph1-, and tandem-cysteine cyanobacterial phytochrome (TCCP) analogs by removal and/or addition of a cysteine residue by site-directed mutagenesis. This structural plasticity contrasts with our inability to generate functional photosensor analogs by analogous site-directed mutagenesis of TCCP and Cph1 representatives. Phylogenetic analysis demonstrates that DCBs do not form a monophyletic clade and also suggest that Cph1 and TCCP families independently emerged from different lineages of cBphPs, possibly via DCB intermediates. Dual-Cys bacteriophytochromes: intermediates in cyanobacterial phytochrome evolution?,Yang HW, Song JY, Song JJ, Kim YW, Rockwell NC, Kim W, Kim H, Lagarias JC, Park YI FEBS J. 2025 Jan 13. doi: 10.1111/febs.17395. PMID:39801362 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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