Light-dependent dimerisation in the N-terminal sensory module of cyanobacterial phytochrome 1

• Published in: FEBS letters Vol. 579; no. 18; pp. 3970 - 3974
• Main Authors: Strauss, Holger M., Schmieder, Peter, Hughes, Jon
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 18.07.2005
• Subjects: Analytical ultracentrifugation; Area Under Curve; AUC; Biophysical Phenomena; Biophysics; Chromatography; Chromatography, Gel; Cph1Δ2; Cyanobacteria - metabolism; Dimerization; Dose-Response Relationship, Drug; farred light (∼720 nm); farred-absorbing form of phytochrome; Histidine sensor kinase; HSK; Internet; Kinetics; Light; Macromolecular Substances - chemistry; N-terminal, photochromic module of cyanobacterial phytochrome 1; PCB; Pfr; Photochemistry; Photoreceptor Cells - metabolism; Phycocyanobilin; Phytochrome; Phytochrome - chemistry; Protein Structure, Quaternary; Protein Structure, Tertiary; r.m.s.d; red light (∼660 nm); red-absorbing form of phytochrome; root mean squared deviation; SAR; Scattering, Radiation; SEC; Signal Transduction; size-exclusion chromatography; specific absorbance ratio; Two-component system; Ultracentrifugation; HSK; Two-component system; Pr; SAR; FR; PCB; AUC; SEC; Signal transduction; R; Histidine sensor kinase; Phytochrome; r.m.s.d; Cph1Δ2; Analytical ultracentrifugation; Pfr
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/j.febslet.2005.06.025

Phytochromes, photoreceptors controlling important physiological processes in plants and many prokaryotes, are photochromic biliproteins. The red-absorbing Pr ground state is converted by light into the farred-absorbing Pfr which can be photoconverted back to Pr. In plants at least Pfr is the physiologically active signalling state. Here, we show that the N-terminal photochromic module of Cph1 homodimerises reversibly and independently in Pr and Pfr, Pfr-dimers being significantly more stable. Implications for the mechanism of signal transduction are discussed.