| Autor: |
Frank, Harry, Cua, Agnes, Chynwat, Veeradej, Young, Andrew, Gosztola, David, Wasielewski, Michael |
| Zdroj: |
Photosynthesis Research; Sep1994, Vol. 41 Issue 3, p389-395, 7p |
| Abstrakt: |
Green plants use the xanthophyll cycle to regulate the flow of energy to chlorophyll a within photosynthetic proteins. Under conditions of low light intensity violaxanthin, a carotenoid possessing nine conjugated double bonds, functions as an antenna pigment by transferring energy from its lowest excited singlet state to that of chlorophyll a within light-harvesting proteins. When the light intensity increases, violaxanthin is biochemically transformed into zeaxanthin, a carotenoid that possesses eleven conjugated double bonds. The results presented here show that extension of the ⧄ conjugation of the polyene lowers the energy of the lowest excited singlet state of the carotenoid below that of chlorophyll a. As a consequence zeaxanthin can act as a trap for the excess excitation energy on chlorophyll a pigments within the protein, thus regulating the flow of energy within photosynthetic light-harvesting proteins. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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