Abstract
In the present study the effect of TBTQ on PS II and its mutual interaction with DCMU was analyzed by measurements of the oxygen yield oscillation pattern and of DCMU binding. It was found: 1) TBTQ in its reduced form is able to induce the reduction of Dox which gives rise to an accelerated decay of S2 and S3 of the wateroxidizing complex. 2) Triton X-100 treatment used for isolation of PS II membrane fragments does not significantly affect the lateral mobility of plastoquinone within the membrane. TBTQ bound to the thylakoid membrane does not enhance the electron pool capacity in PS II membrane fragments. 3) Preincubation of thylakoids with TBTQ diminishes the blockage of 02-evolution by DCMU significantly. In correspondence with previous findings [18, 19] the effect strongly depends on the order of addition of TBTQ and DCMU. 4) Excitation with a single saturating flash causes enhanced DCMU binding in TBTQ pretreated samples leading to the inhibition of flash induced oxygen evolution. The rate of the latter process depends on the DCMU concentration. 5) In thylakoids pretreated in the dark with TBTQ the oxygen yield of the 3rd flash slowly declines as a function of dark incubation time at constant DCMU concentration. Based on the above mentioned findings it is inferred that a mutual interaction between TBTQ and DCMU takes place at the PS II acceptor side. Two alternative mechanisms are discussed: i) TBTQ tightly (covalently?) bound at the QB-site (or very close to it) is modified in its function by DCMU via structural effects (allosteric type), or ii) there occurs a TBTQ/DCMU exchange that is fast in the light and slow in the dark.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 423-430 |
| Number of pages | 8 |
| Journal | Zeitschrift fur Naturforschung - Section C Journal of Biosciences |
| Volume | 44 |
| Issue number | 5-6 |
| DOIs | |
| State | Published - Jun 1 1989 |
| Externally published | Yes |
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Keywords
- Binding Sites
- Halogenated p-Benzoquinones
- Oxygen Yield Oscillation
- Photosystem II
- Quinone/Herbicide Interaction
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
Cite this
Tribromotoluquinone Induced Modifications of the Oscillation Pattern of Oxygen Evolution and of Herbicide Binding in Thylakoids and PS II Membrane Fragments from Spinach. / Renger, G.; Messinger, J.; Fromme, Raimund.
In: Zeitschrift fur Naturforschung - Section C Journal of Biosciences, Vol. 44, No. 5-6, 01.06.1989, p. 423-430.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Tribromotoluquinone Induced Modifications of the Oscillation Pattern of Oxygen Evolution and of Herbicide Binding in Thylakoids and PS II Membrane Fragments from Spinach
AU - Renger, G.
AU - Messinger, J.
AU - Fromme, Raimund
PY - 1989/6/1
Y1 - 1989/6/1
N2 - In the present study the effect of TBTQ on PS II and its mutual interaction with DCMU was analyzed by measurements of the oxygen yield oscillation pattern and of DCMU binding. It was found: 1) TBTQ in its reduced form is able to induce the reduction of Dox which gives rise to an accelerated decay of S2 and S3 of the wateroxidizing complex. 2) Triton X-100 treatment used for isolation of PS II membrane fragments does not significantly affect the lateral mobility of plastoquinone within the membrane. TBTQ bound to the thylakoid membrane does not enhance the electron pool capacity in PS II membrane fragments. 3) Preincubation of thylakoids with TBTQ diminishes the blockage of 02-evolution by DCMU significantly. In correspondence with previous findings [18, 19] the effect strongly depends on the order of addition of TBTQ and DCMU. 4) Excitation with a single saturating flash causes enhanced DCMU binding in TBTQ pretreated samples leading to the inhibition of flash induced oxygen evolution. The rate of the latter process depends on the DCMU concentration. 5) In thylakoids pretreated in the dark with TBTQ the oxygen yield of the 3rd flash slowly declines as a function of dark incubation time at constant DCMU concentration. Based on the above mentioned findings it is inferred that a mutual interaction between TBTQ and DCMU takes place at the PS II acceptor side. Two alternative mechanisms are discussed: i) TBTQ tightly (covalently?) bound at the QB-site (or very close to it) is modified in its function by DCMU via structural effects (allosteric type), or ii) there occurs a TBTQ/DCMU exchange that is fast in the light and slow in the dark.
AB - In the present study the effect of TBTQ on PS II and its mutual interaction with DCMU was analyzed by measurements of the oxygen yield oscillation pattern and of DCMU binding. It was found: 1) TBTQ in its reduced form is able to induce the reduction of Dox which gives rise to an accelerated decay of S2 and S3 of the wateroxidizing complex. 2) Triton X-100 treatment used for isolation of PS II membrane fragments does not significantly affect the lateral mobility of plastoquinone within the membrane. TBTQ bound to the thylakoid membrane does not enhance the electron pool capacity in PS II membrane fragments. 3) Preincubation of thylakoids with TBTQ diminishes the blockage of 02-evolution by DCMU significantly. In correspondence with previous findings [18, 19] the effect strongly depends on the order of addition of TBTQ and DCMU. 4) Excitation with a single saturating flash causes enhanced DCMU binding in TBTQ pretreated samples leading to the inhibition of flash induced oxygen evolution. The rate of the latter process depends on the DCMU concentration. 5) In thylakoids pretreated in the dark with TBTQ the oxygen yield of the 3rd flash slowly declines as a function of dark incubation time at constant DCMU concentration. Based on the above mentioned findings it is inferred that a mutual interaction between TBTQ and DCMU takes place at the PS II acceptor side. Two alternative mechanisms are discussed: i) TBTQ tightly (covalently?) bound at the QB-site (or very close to it) is modified in its function by DCMU via structural effects (allosteric type), or ii) there occurs a TBTQ/DCMU exchange that is fast in the light and slow in the dark.
KW - Binding Sites
KW - Halogenated p-Benzoquinones
KW - Oxygen Yield Oscillation
KW - Photosystem II
KW - Quinone/Herbicide Interaction
UR - http://www.scopus.com/inward/record.url?scp=84961490007&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84961490007&partnerID=8YFLogxK
U2 - 10.1515/znc-1989-5-614
DO - 10.1515/znc-1989-5-614
M3 - Article
VL - 44
SP - 423
EP - 430
JO - Zeitschrift fur Naturforschung - Section C Journal of Biosciences
JF - Zeitschrift fur Naturforschung - Section C Journal of Biosciences
SN - 0939-5075
IS - 5-6
ER -