Journal article

Publication year: 2011

Pages: 6178-6188

Journal: Biochemistry

Volume number: 50

Issue number: 28

ISSN: 0006-2960

DOI Link: https://doi.org/10.1021/bi200612d

Publisher: American Chemical Society

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 Mn2+. 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.

Harvard Citation style: Psakis, G., Mailliet, J., Lang, C., Teufel, L., Essen, L. and Hughes, J. (2011) Signaling Kinetics of Cyanobacterial Phytochrome Cph1, a Light Regulated Histidine Kinase, Biochemistry, 50(28), pp. 6178-6188. https://doi.org/10.1021/bi200612d

APA Citation style: Psakis, G., Mailliet, J., Lang, C., Teufel, L., Essen, L., & Hughes, J. (2011). Signaling Kinetics of Cyanobacterial Phytochrome Cph1, a Light Regulated Histidine Kinase. Biochemistry. 50(28), 6178-6188. https://doi.org/10.1021/bi200612d