Work

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

Year: 2005

Type: article

Abstract: 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 approximately 40%. The antenna carotenoid extends the wavelength range of the collection of light for uphill transmembrane proton transport.

Source: Science

DOI: 10.1126/science.1118046

Authors: Sergei P. Balashov, Eleonora S. Imasheva, Vladimir A. Boichenko, Josefa Antón, Jennifer M. Wang, Janos K. Lanyi

Institutions: University of Alicante, Russian Academy of Sciences, University of California, Irvine, Institute of Basic Biological Problems

Language: English

Topic: Photoreceptor and optogenetics research

Subfield: Cellular and Molecular Neuroscience

Field: Neuroscience

Domain: Life Sciences

Open Access status: green

Funder: National Institute of General Medical Sciences

Awards: LIGHT-DRIVEN ION TRANSPORT IN BACTERIAL RHODOPSINS, G3307643445