Photoinhibition of photosystem I is accelerated by dimethyldithiocarbamate, an inhibitor of superoxide dismutase, during light-chilling of spinach leaves.
In vivo photoinhibition of photosystem I (PS I) was investigated at chilling temperature using the leaves of the chilling-resistant spinach plant treated with an inhibitor of superoxide dismutase, diethyldithiocarbamate (DDC). When spinach leaves were treated with DDC during chilling at 4 degrees C for 12 h with a light intensity of 120 micromol m(-2) s(-1), the activity of PS I and the content of iron-sulfur centers declined to about 50% and 25% of the non-DDC-treated controls, respectively. A native green gel analysis of thylakoid membranes isolated from the DDC-treated leaves resolved a novel chlorophyll-protein complex, which was identified as the light-harvesting complex I (LHC I)-deficient PS I complex when examined by 77 K fluorescence spectroscopy and two-dimensional sodium dodecyl sulfate gel electrophoresis. The possible dissociation of LHC I as an early structural change in the PS I complex after DDC-induced photoinhibition of PS I is discussed.
Hwang
Hong Jin
HJ
Department of Molecular Biology, Pusan National University, Busan 609-735, South Korea.
Kim
Jin-Hong
JH
Eu
Young-Jae
YJ
Moon
Byoung Yong
BY
Cho
Sung Ho
SH
Lee
Choon-Hwan
CH
D004125:Dimethyldithiocarbamate / Q000494:pharmacology*; D015180:Electrophoresis, Gel, Two-Dimensional; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D008027:Light; D045331:Photosystem I Protein Complex / Q000037:antagonists & inhibitors*; D018515:Plant Leaves / Q000378:metabolism / Q000528:radiation effects; D013050:Spectrometry, Fluorescence; D018724:Spinacia oleracea / Q000378:metabolism / Q000528:radiation effects*; D013482:Superoxide Dismutase / Q000037:antagonists & inhibitors*
D004125:Dimethyldithiocarbamate; D004791:Enzyme Inhibitors; D045331:Photosystem I Protein Complex; D013482:Superoxide Dismutase