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Signaling kinetics of cyanobacterial phytochrome Cph1, a light regulated histidine kinase.
- Source :
-
Biochemistry [Biochemistry] 2011 Jul 19; Vol. 50 (28), pp. 6178-88. Date of Electronic Publication: 2011 Jun 22. - Publication Year :
- 2011
-
Abstract
- Cyanobacterial phytochrome 1 (Cph1) is a red/far-red light regulated histidine kinase, which together with its response regulator (Rcp1) forms a two-component light signaling system in Synechocystis 6803. In the present study we followed the in vitro autophosphorylation of Cph1 and the subsequent phosphotransfer to Rcp1 in different ionic milieus and following different light treatments. Both processes were red/far-red reversible with activity manifested in the Pr ground state (in darkness or after far-red irradiation) and with strongest activities being exhibited in the presence of Mn(2+). In vivo and in vitro assembled holoproteins in the Pr state displayed at least 4-fold higher efficiencies (k(cat)/K(m)) for autophosphorylation and phosphotransfer than the apoprotein or the holoprotein at photoequilibrium in red light. The reduced activities observed following red light treatments were consistent with the Pfr state being enzymatically inactive. Thus, both the rate of kinase autophosphorylation and the rate of phosphotransfer regulate the phosphorylation state of the response regulator, consistent with the rotary switch model regulating accessibility of the histidine target.
- Subjects :
- Bacterial Proteins metabolism
Bacterial Proteins radiation effects
Cations, Divalent chemistry
Histidine Kinase
Hydrogen-Ion Concentration
Kinetics
Manganese chemistry
Phosphoproteins chemistry
Phosphoproteins physiology
Phosphoproteins radiation effects
Phosphorylation radiation effects
Photoreceptors, Microbial
Phytochrome radiation effects
Protein Kinases radiation effects
Signal Transduction radiation effects
Synechocystis radiation effects
Ultraviolet Rays
Bacterial Proteins chemistry
Bacterial Proteins physiology
Light
Phytochrome chemistry
Phytochrome physiology
Protein Kinases chemistry
Protein Kinases metabolism
Protein Kinases physiology
Signal Transduction physiology
Synechocystis enzymology
Subjects
Details
- Language :
- English
- ISSN :
- 1520-4995
- Volume :
- 50
- Issue :
- 28
- Database :
- MEDLINE
- Journal :
- Biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 21634374
- Full Text :
- https://doi.org/10.1021/bi200612d