This HPLC-based system allowed us to quantify oxidized and reduced … These mutants possess active PSII and reduce plastoquinone (PQ) but cannot oxidize plastoquinol (PQH2) via light-dependent reduction of NADP. Please enable it to take advantage of the complete set of features! Time-resolved visible and infrared difference spectroscopy for the study of photosystem I with different quinones incorporated into the A1 binding site. The energized electrons are replaced by oxidizing water, to form hydrogen ions and molecular oxygen, as shown in Fig. THE KINETICS OF PLASTOQUINONE POOL REOXIDATION IN MOUGEOTIA SP. not otherwise permitted to reproduce, republish, redistribute, or sell any Supporting Information -, Photosynth Res. Hiroki Makita, Nan Zhao, Gary Hastings. PY - 2011/12/27. http://pubs.acs.org/page/copyright/permissions.html. plastoquinol at the Qo site of the cytochromeb6/f complex is considered to be the slowest step in the linear electron transport chain, with a turnover time of 3.3–5ms[37]. 338 Catalysed Reduction of Plastocyanin by Plastoquinol-I They found that plastoquinone-I was as effective as plastoquinone-9, but further reduction of the carbon skeleton of the side chain caused almost complete loss of activity. In Photosystem 1 (PS1), phylloquinone (PhQ) acts as a secondary electron acceptor from chlorophyll ec3 and also as an electron donor to the iron–sulfur cluster FX. The cytochrome b 6 f complex (plastoquinol—plastocyanin reductase; EC 1.10.99.1) is an enzyme found in the thylakoid membrane in chloroplasts of plants, cyanobacteria, and green algae, that catalyzes the transfer of electrons from plastoquinol to plastocyanin. By comparison, upstream electron transport from H 2O to PSII centers and from Q A to diffusible PQ occurs with turnover times in the range of 1–2ms[38,39]. This corresponds to the events from the PSIdriven electron transfer to the end electron acceptors on the PSI acceptor side ([NADP.sup.+]), starting at [PQH.sub.2] (plastoquinol). plastoquinol PQH 2 The conversion to the more stable oxidized form facilitates the separation and the collection of the purified PQ. PSII reduces PQ to PQH 2 (plastoquinol), the fully reduced form of PQ. Indeed it has been shown [15,16] that a substantial fraction (30-40%) of the extracted plastoquinone is in the doubly reduced and protonated form, i.e. Light-driven quinone reduction in heliobacterial membranes. Upon photoactivation of PSII, PLQ is double reduced and takes up … redistribute this material, requesters must process their own requests via the RightsLink permission This article is cited by Plastoquinol A (all-E)-2,3-dimethyl-5-(3,7,11,15,19,23,27,31,35-nonamethyl-2,6,10,14,18,22,26,30,34-hexatricontanonaenyl)-1,4-benzenediol in Nat Struct Mol Biol 16:334-342, 2009), allowing to rule out the proposed "alternating" mechanism of plastoquinol-plastoquinone exchange, while giving support to the "single-channel" one. Plastoquinone-9 (PQ-9) is an essential component of photosynthesis that carries electrons in the linear and alternative electron transport chains, and is also a redox sensor that regulates state transitions and gene expression. Diffusing in the … Y1 - 2011/12/27.  |  Diffusing in the membrane, PQH 2 reaches the Cyt b 6 f complex. PQH 2 donates two electrons to Cyt b 6 f and releases two protons into the intra‐thylakoid lumen. Define plastoquinone. Semenov, Boris N. Ivanov. Epub 2019 Apr 2. http://pubs.acs.org/page/copyright/permissions.html, https://doi.org/10.1007/s11120-020-00760-9, https://doi.org/10.1016/j.bbabio.2018.08.003, https://doi.org/10.1007/s11120-018-0496-x, https://doi.org/10.1007/s11120-018-0503-2, https://doi.org/10.1007/s11120-018-0480-5, https://doi.org/10.1016/j.bbabio.2014.12.007, https://doi.org/10.1016/j.bpj.2015.01.009, https://doi.org/10.1016/j.febslet.2014.10.003. 2008 Oct-Dec;98(1-3):53-80. doi: 10.1007/s11120-008-9345-7. Evolution of photosynthetic reaction centers: insights from the structure of the heliobacterial reaction center. Mackey*, Adina Paytan, Ken Caldeira, Arthur R. Grossman, Dawn Moran, The duration of the inhibitory effect, as tested here and in the previous study [19], was, in both cases, related to the nature of the antioxidant moiety, decreasing in the series [alpha]-tocopherol ~ ubiquinol > plastoquinol, independently of the rest of the structure of the antioxidant; compare Figures 5-7, 9, and 10, Table 1, and [19]. The duration of the inhibitory effect, as tested here and in the previous study [19], was, in both cases, related to the nature of the antioxidant moiety, decreasing in the series [alpha]-tocopherol ~ ubiquinol > plastoquinol, independently of the rest of the structure of the antioxidant; compare Figures 5-7, 9, and 10, Table 1, and [19]. The Cyt b 6 f complex reduces Pc. Plastoquinone and ubiquinone can scavenge free radicals to prevent lipid peroxidation, protein oxidation and DNA damage in plant response to biotic and abiotic stresses. The reduction of electron acceptors such as [NADP.sup.+], and energy requirements as ATP, depending on enzyme-sensitive [Na.sup.+] and [Cl.sup.-] are undermining the activity cycle of carbon fixation (ABDEL-LATIF, 2008) can also be a reason for the rate of reoxidation of the plastoquinone (Qa) being less than the rate of reduction, thus leading to a reduction of … Clipboard, Search History, and several other advanced features are temporarily unavailable. Article Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. Photosystem-II D1 protein mutants of Chlamydomonas reinhardtii in relation to metabolic rewiring and remodelling of H-bond network at Q, J Mol Graph Model. A distinct dynamic behavior of PSII in the presence of plastoquinol is observed which, coupled to changes in charge distribution and electrostatic interactions, causes disruption of the interactions seen in the PSII-plastoquinone complex and leads to the "squeezing out" of plastoquinol from the binding pocket. Photosystem II: The machinery of photosynthetic water splitting. PQH 2 donates two electrons to Cyt b 6 f and releases two protons into the intra‐thylakoid lumen. 2 Find out information about Plastoquinol. NIH Plastoquinol, the reduced form, also functions as an antioxidant by reducing reactive oxygen species, some produced from the … However, little is known about the functions of fibrillins in leaf tissues. What does PLASTOQUINONE mean? -, Biochemistry. 122 plastoquinone-9 (plastoquinol-9) in one disc after a dark-adaptation period of 2 h. The dark-adapted 123 samples were frozen in liquid nitrogen after 3-s illumination with farred light to ensure full oxidation - 124 of the photoactive pool of plastoquinone. However, a large fraction of the PQ pool is located outside the thylakoid membranes, in the plastoglobules and the chloroplast envelopes, reflecting a wider … The reduction of plastoquinone to plastoquinol dynamics of the plastoquinone binding pocket and plasto- lowers PSII affinity for the latter and leads to its release. 2018 Nov 10;24(12):337. doi: 10.1007/s00894-018-3858-6. 2007 Oct 9;46(40):11398-409 HHS Would you like email updates of new search results? in Nat Struct Mol Biol 16:334–342, 2009), allowing to rule out the proposed “alternating” mechanism of plastoquinol–plastoquinone exchange, while giving support to the “single-channel” one. Dynamics: a new insight into breast cancer treatment D. McConnell, David Lowry, Troy N. Rowan, van. 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