English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
 
 
DownloadE-Mail
  Phytochromes with noncovalently bound chromophores: The ability of apophytochromes to direct tetrapyrrole photoisomerization

Jorissen, H. J. M. M., Quest, B., Lindner, I., de Marsac, N. T., & Gärtner, W. (2002). Phytochromes with noncovalently bound chromophores: The ability of apophytochromes to direct tetrapyrrole photoisomerization. Photochemistry and Photobiology, 75(5), 554-559.

Item is

Basic

show hide
Genre: Journal Article
Alternative Title : Photochem. Photobiol.

Files

show Files

Locators

show

Creators

show
hide
 Creators:
Jorissen, H. J. M. M., Author
Quest, B.1, Author              
Lindner, I., Author
de Marsac, N. T., Author
Gärtner, W.1, Author              
Affiliations:
1External Organizations, ou_persistent22              

Content

show
hide
Free keywords: -
 Abstract: Chromophore-apoprotein interactions were studied with recombinant apoproteins, oat phytochrome (phyA) and CphB of the cyanobacterium Calothrix PCC7601, which were both incubated with the bilin compounds biliverdin (BV) IXalpha, phycocyanobilin (PCB) and the 3'-methoxy derivative of PCB. Previously it was shown that CphB and its homolog in Calothrix, CphA, show strong sequence similarities with each other and with the phytochromes of higher and lower plants, despite the fact that CphB carries a leucine instead of a cysteine at the chromophore attachment position and thus holds the chromophore only noncovalently. CphA binds tetrapyrrole chromophores in a covalent, phytochrome-like manner. For both cyanobacterial phytochromes, red and far-red light-induced photochemistry has been reported. Thus, the role of the binding site of CphB in directing the photochemistry of noncovalently bound tetrapyrroles was analyzed in comparison with the apoprotein from phyA phytochrome. Both the aforementioned compounds, which were used as chromophores, are not able to form covalent bonds with a phyto chrome-type apoprotein because of their chemical structure (vinyl group at position 3 or methoxy group at position 3'). The BV adducts of both apoproteins showed phytochrome-like photochemistry (formation of red and far-red- absorbing forms of phytochrome [P-r and P-fr forms]). However, incubation of the oat apophytochrome with BV primarily yields a 700 nm form from which the P-r-P-fr, photochemistry can be initiated and to which the system relaxes in the dark after illumination. The results for CphB were compared with a CphB mutant where the chromophore-binding cysteine had been introduced, which, upon incubation with PCB, shows spectral properties nearly identical with its (covalently binding) CphA homolog. A comparison of the spectral properties P-r and P-fr forms) of all the PCB- and BV-containing chromoproteins reveals that the binding site of the cyanobacterial apoprotein is better suited than the plant (oat) phytochrome to noncovalently incorporate the chromophore and to regulate its photochemistry. Our findings support the proposal that the recently identified phytochrome-like prokaryotic photoreceptors, which do not contain a covalently bound chromophore, may trigger a light- induced physiological response.

Details

show
hide
Language(s): eng - English
 Dates: 2002-05
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: eDoc: 39335
ISI: 000175490100017
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: Photochemistry and Photobiology
  Alternative Title : Photochem. Photobiol.
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: -
Pages: - Volume / Issue: 75 (5) Sequence Number: - Start / End Page: 554 - 559 Identifier: ISSN: 0031-8655