Send to

Choose Destination
Biochemistry. 2003 Feb 4;42(4):1008-15.

Oxidation of the two beta-carotene molecules in the photosystem II reaction center.

Author information

Wolfson Laboratories, Department of Biological Sciences, Imperial College of Science, Technology and Medicine, London SW7 2AY, UK.


We present a spectroscopic characterization of the two nonequivalent beta-carotene molecules in the photosystem II reaction center. Their electronic and vibrational properties exhibit significant differences, reflecting a somewhat different configuration for these two cofactors. Both carotenoid molecules are redox-active and can be oxidized by illumination of the reaction centers in the presence of an electron acceptor. The radical cation species show similar differences in their spectroscopic properties. The results are discussed in terms of the structure and unusual function of these carotenoids. In addition, the attribution of resonance Raman spectra of photosystem II preparations excited in the range 800-900 nm is discussed. Although contributions of chlorophyll cations cannot be formally ruled out, our results demonstrate that these spectra mainly arise from the cation radical species of the two carotenoids present in photosystem II reaction centers.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for American Chemical Society
Loading ...
Support Center