6BHO
Green Light-Absorbing State of NpR6012g4, a Red/Green Cyanobacteriochrome
Summary for 6BHO
| Entry DOI | 10.2210/pdb6bho/pdb |
| Related | 6BHN |
| NMR Information | BMRB: 26577 |
| Descriptor | Methyl-accepting chemotaxis sensory transducer with phytochrome sensor, PHYCOCYANOBILIN (2 entities in total) |
| Functional Keywords | cbcr, phytochrome, bilin, cyanobacteria, signaling protein |
| Biological source | Nostoc punctiforme PCC 73102 |
| Total number of polymer chains | 1 |
| Total formula weight | 20990.50 |
| Authors | Lim, S.,Yu, Q.,Rockwell, N.C.,Martin, S.S.,Lagarias, J.C.,Ames, J.B. (deposition date: 2017-10-31, release date: 2018-04-18, Last modification date: 2024-10-23) |
| Primary citation | Lim, S.,Yu, Q.,Gottlieb, S.M.,Chang, C.W.,Rockwell, N.C.,Martin, S.S.,Madsen, D.,Lagarias, J.C.,Larsen, D.S.,Ames, J.B. Correlating structural and photochemical heterogeneity in cyanobacteriochrome NpR6012g4. Proc. Natl. Acad. Sci. U.S.A., 115:4387-4392, 2018 Cited by PubMed Abstract: Phytochrome photoreceptors control plant growth, development, and the shade avoidance response that limits crop yield in high-density agricultural plantings. Cyanobacteriochromes (CBCRs) are distantly related photosensory proteins that control cyanobacterial metabolism and behavior in response to light. Photoreceptors in both families reversibly photoconvert between two photostates via photoisomerization of linear tetrapyrrole (bilin) chromophores. Spectroscopic and biochemical studies have demonstrated heterogeneity in both photostates, but the structural basis for such heterogeneity remains unclear. We report solution NMR structures for both photostates of the red/green CBCR NpR6012g4 from In addition to identifying structural changes accompanying photoconversion, these structures reveal structural heterogeneity for residues Trp655 and Asp657 in the red-absorbing NpR6012g4 dark state, yielding two distinct environments for the phycocyanobilin chromophore. We use site-directed mutagenesis and fluorescence and absorbance spectroscopy to assign an orange-absorbing population in the NpR6012g4 dark state to the minority configuration for Asp657. This population does not undergo full, productive photoconversion, as shown by time-resolved spectroscopy and absorption spectroscopy at cryogenic temperature. Our studies thus elucidate the spectral and photochemical consequences of structural heterogeneity in a member of the phytochrome superfamily, insights that should inform efforts to improve photochemical or fluorescence quantum yields in the phytochrome superfamily. PubMed: 29632180DOI: 10.1073/pnas.1720682115 PDB entries with the same primary citation |
| Experimental method | SOLUTION NMR |
Structure validation
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