Investigation of the molecular mechanism of the blue-light-specific excitation energy quenching in the plant antenna complex LHCII.
Excitation of the major photosynthetic antenna complex of plants, LHCII, with blue light (470nm) provides an advantage to plants, as it gives rise to chlorophyll a fluorescence lifetimes shorter than with excitation with red light (635nm). This difference is particularly pronounced in fluorescence emission wavelengths longer than 715nm. Illumination of LHCII preparation with blue light additionally induces fluorescence quenching, which develops on a minute timescale. This effect is much less efficient when induced by red light, despite the equalized energy absorbed in both the spectral regions. Simultaneous analysis of the fluorescence and photoacoustic signals in LHCII demonstrated that the light-driven fluorescence quenching is not associated with an increase in heat emission. Instead, a reversible light-induced conformational transformation of the protein takes place, as demonstrated by the FTIR technique. These findings are discussed in terms of the blue-light-specific excitation energy quenching in LHCII, which may have photoprotective applications.
Department of Biophysics, Institute of Physics, Maria Curie-Sklodowska University, 20 031 Lublin, Poland. wieslaw.gruszecki@umcs.pl
Wieslaw I
WI
Gruszecki
Monika
M
Zubik
Rafal
R
Luchowski
Wojciech
W
Grudzinski
Malgorzata
M
Gospodarek
Janusz
J
Szurkowski
Zygmunt
Z
Gryczynski
Ignacy
I
Gryczynski
D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D005453:Fluorescence; D008027:Light; D010788:Photosynthesis; D045322:Photosynthetic Reaction Center Complex Proteins; D018724:Spinacia oleracea / Q000378:metabolism / Q000502:physiology*
D045322:Photosynthetic Reaction Center Complex Proteins; D002734:Chlorophyll; D000077194:Chlorophyll A