Interaction of 2-n-heptyl-4-hydroxyquinoline-N-oxide with photosystem II in chloroplasts and subchloroplast particles.
The effects of 2-n-heptyl-4-hydroxyquinoline-N-oxide on electron transport in thylakoids and oxygen-evolving photosystem II particles has been examined. Kinetic fluorescence studies reveal that the site of inhibition for alkyl derivatives of hydroxyquinoline-N-oxide (I50 approximately equal to 2 microM) is located between Q and plastoquinone. Studies with thylakoids isolated from atrazine-resistant pigweed plants indicate that the modification in the Q/B membrane complex that confers increased resistance to inhibition by atrazine also results in decreased sensitivity to inhibition by 2-n-heptyl-4-hydroxyquinoline-N-oxide (resistant/ sensitive ratio = 11). From the results of tetramethylphenylenediamine by-pass experiments, determinations of inhibitor sensitivity in trypsin-treated thylakoids and competitive displacement experiments made with [14C]metribuzin in thylakoids and photosystem II particles, it is suggested that 2-n-heptyl-4-hydroxyquinoline-N-oxide binds in a region of the Q/B complex that is distinct from the 3-(3,4-dichloro)-1,1-dimethyl urea and atrazine binding sites.
Barton
J R
JR
School of Biological Sciences, University of Kentucky, Lexington, Kentucky 40506, USA.
MacPeek
W A
WA
Cohen
W S
WS
D027721:Amaranthus / Q000187:drug effects / Q000378:metabolism; D001280:Atrazine / Q000494:pharmacology; D002736:Chloroplasts / Q000187:drug effects* / Q000378:metabolism*; D004237:Diuron / Q000494:pharmacology; D004579:Electron Transport / Q000187:drug effects; D005292:Ferricyanides / Q000494:pharmacology; D006540:Herbicides / Q000378:metabolism / Q000494:pharmacology; D006912:Hydroxyquinolines / Q000378:metabolism / Q000494:pharmacology*; D018532:Pisum sativum / Q000187:drug effects / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000187:drug effects* / Q000378:metabolism*; D010847:Picolines / Q000494:pharmacology; D020524:Thylakoids / Q000187:drug effects / Q000378:metabolism; D014227:Triazines / Q000378:metabolism / Q000494:pharmacology
C524030:1-(3-picolinium)-12-triethylammonium-dodecane dibromide; D005292:Ferricyanides; D006540:Herbicides; D006912:Hydroxyquinolines; D045332:Photosystem II Protein Complex; D010847:Picolines; D014227:Triazines; C007931:hexacyanoferrate III; C001333:2-(n-heptyl)-4-hydroxyquinoline N-oxide; D004237:Diuron; D001280:Atrazine; C009235:metribuzin