Help Privacy Policy Disclaimer
  Advanced SearchBrowse


  Two independent, light-sensing two-component systems in a filamentous cyanobacterium

Jorissen, H. J. M. M., Quest, B., Remberg, A., Coursin, T., Braslavsky, S. E., Schaffner, K., et al. (2002). Two independent, light-sensing two-component systems in a filamentous cyanobacterium. European Journal of Biochemistry, 269(11), 2662-2671.

Item is


show hide
Genre: Journal Article
Alternative Title : Eur. J. Biochem.


show Files




Jorissen, H. J. M. M., Author
Quest, B.1, Author              
Remberg, A., Author
Coursin, T., Author
Braslavsky, S. E., Author
Schaffner, K., Author
de Marsac, N. T., Author
Gärtner, W.2, Author              
1Oesterhelt, Dieter / Membrane Biochemistry, Max Planck Institute of Biochemistry, Max Planck Society, ou_1565164              
2External Organizations, ou_persistent22              


Free keywords: Calothrix sp strain PCC 7601; flash photolysis; heterologous expression; phytochrome-like apoproteins CphA and CphB; response regulators RcpA and RcpB
 Abstract: Two ORFs, cphA and cphB , encoding proteins CphA and CphB with strong similarities to plant phytochromes and to the cyanobacterial phytochrome Cph1 of Synechocystis sp. PCC 6803 have been identified in the filamentous cyanobacterium Calothrix sp. PCC7601. While CphA carries a cysteine within a highly conserved amino-acid sequence motif, to which the chromophore phytochromobilin is covalently bound in plant phytochromes, in CphB this position is changed into a leucine. Both ORFs are followed by rcpA and rcpB genes encoding response regulator proteins similar to those known from the bacterial two-component signal transduction. In Calothrix , all four genes are expressed under white light irradiation conditions, albeit in low amounts. For heterologous expression and convenient purification, the cloned genes were furnished with His-tag encoding sequences at their 3' end and expressed in Escherichia coli . The two recombinant apoproteins CphA and CphB bound the chromophore phycocyanobilin (PCB) in a covalent and a noncovalent manner, respectively, and underwent photochromic absorption changes reminiscent of the P-r and P-fr forms (red and far-red absorbing forms, respectively) of the plant phytochromes and Cph1. A red shift in the absorption maxima of the CphB/PCB complex (lambda(max) = 685 and 735 nm for P-r and P-fr , respectively) is indicative for a noncovalent incorporation of the chromophore (lambda(max) of P- r , P-fr of CphA: 663, 700 nm). A CphB mutant generated at the chromophore-binding position (Leu246-->Cys) bound the chromophore covalently and showed absorption spectra very similar to its paralog CphA, indicating the noncovalent binding to be the only cause for the unexpected absorption properties of CphB. The kinetics of the light-induced P-fr formation of the CphA-PCB chromoprotein, though similar to that of its ortholog from Synechocystis , showed differences in the kinetics of the P-fr formation. The kinetics were not influenced by ATP (probing for autophosphorylation) or by the response regulator. In contrast, the light-induced kinetics of the CphB-PCB complex was markedly different, clearly due to the noncovalently bound chromophore.


Language(s): eng - English
 Dates: 2002-06
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: eDoc: 28943
ISI: 000175906900004
 Degree: -



Legal Case


Project information


Source 1

Title: European Journal of Biochemistry
  Alternative Title : Eur. J. Biochem.
Source Genre: Journal
Publ. Info: -
Pages: - Volume / Issue: 269 (11) Sequence Number: - Start / End Page: 2662 - 2671 Identifier: ISSN: 0014-2956