NADPH Dehydrogenase-mediated respiratory electron transport in thylakoid membranes of the cyanobacterium Synechocystis sp. PCC 6803 is inactive in the light
Date
2003
Authors
Ryu, Kwon-Sang
Suh, Kye-Hong
Chung, Young-Ho
Park, Young-Mok
Chow, Wah S (Fred)
Park, Youn-Il
Journal Title
Journal ISSN
Volume Title
Publisher
Korean Society of Molecular and Cell Biology
Abstract
Non-photochemical redox changes of the plastoquinone pools in darkness were investigated in the cyanobacterium Synechocystis sp. PCC 6803 by monitoring changes in Chl fluorescence yield during light-to-dark transitions. The inhibitors rotenone and mercury with or without 1 mM succinate fully suppressed the postillumination increase in Chl fluorescence in both NADPH dehydrogenase-defective (M55) and ΔCtaI cells. The latter cells lack subunit I of cytochrome aa3-type cytochrome c oxidase. These results strongly suggest that NADPH dehydrogenase plays the major role in electron donation in the non-photo-chemical reduction of plastoquinone. The rising phase of post-illumination Chl fluorescence in both wild type pretreated with KCN, and ΔCtaI cells, was significantly slowed by low light illumination. We detected comparable photochemical levels of both photosystem (PS) II and PSI during steady state illumination in wild type and ΔCtaI cells. From these results, we suggest that respiratory electron flow involved in the non-photochemical redox change of plastoquinone is not likely to occur in the light.
Description
Keywords
Keywords: reduced nicotinamide adenine dinucleotide phosphate dehydrogenase; cytochrome c oxidase; mercury; plastoquinone; rotenone; succinic acid; article; Cyanobacterium; electron transport; enzymology; light; physiology; spectrofluorometry; thylakoid; fluorescen Cytochrome aa3 Oxidase; Light Inactivation; NADPH Dehydrogenase; Synechocystis sp. PCC 6803
Citation
Collections
Source
Molecules and Cells
Type
Journal article