Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Site Tools

  • AAAS
  • Subscribe
  • Feedback

Site Search

Search Advanced

Science 23 September 2005:
Vol. 309. no. 5743, pp. 2061 - 2064
DOI: 10.1126/science.1118046
Prev | Table of Contents | Next

Reports

Xanthorhodopsin: A Proton Pump with a Light-Harvesting Carotenoid Antenna

Sergei P. Balashov,1* Eleonora S. Imasheva,1 Vladimir A. Boichenko,2 Josefa Antón,3 Jennifer M. Wang,1 Janos K. Lanyi1*

Energy transfer from light-harvesting carotenoids to chlorophyll is common in photosynthesis, but such antenna pigments have not been observed in retinal-based ion pumps and photoreceptors. Here we describe xanthorhodopsin, a proton-pumping retinal protein/carotenoid complex in the eubacterium Salinibacter ruber. The wavelength dependence of the rate of pumping and difference absorption spectra measured under a variety of conditions indicate that this protein contains two chromophores, retinal and the carotenoid salinixanthin, in a molar ratio of about 1:1. The two chromophores interact strongly, and light energy absorbed by the carotenoid is transferred to the retinal with a quantum efficiency of ~40%. The antenna carotenoid extends the wavelength range of the collection of light for uphill transmembrane proton transport.

1 University of California, Irvine, CA 92697, USA.
2 Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, 142290, Russia.
3 University of Alicante, Alicante, E-03080, Spain.

* To whom correspondence should be addressed. E-mail: balashov{at}uci.edu (S.P.B.); jlanyi{at}orion.oac.uci.edu (J.K.L.)

Read the Full Text


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Crystallographic structure of xanthorhodopsin, the light-driven proton pump with a dual chromophore.
H. Luecke, B. Schobert, J. Stagno, E. S. Imasheva, J. M. Wang, S. P. Balashov, and J. K. Lanyi (2008)
PNAS 105, 16561-16565
   Abstract »    Full Text »    PDF »
Salinibacter Sensory Rhodopsin: SENSORY RHODOPSIN I-LIKE PROTEIN FROM A EUBACTERIUM.
T. Kitajima-Ihara, Y. Furutani, D. Suzuki, K. Ihara, H. Kandori, M. Homma, and Y. Sudo (2008)
J. Biol. Chem. 283, 23533-23541
   Abstract »    Full Text »    PDF »
The genome of Salinibacter ruber: Convergence and gene exchange among hyperhalophilic bacteria and archaea.
E. F. Mongodin, K. E. Nelson, S. Daugherty, R. T. DeBoy, J. Wister, H. Khouri, J. Weidman, D. A. Walsh, R. T. Papke, G. Sanchez Perez, et al. (2005)
PNAS 102, 18147-18152
   Abstract »    Full Text »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)