(1994) reported increased sensitivity to high light in mutants of Synechocystis PCC 6714. However, hydrogen can be considered in a hybrid furnace design in place of fossil fuel, where it is typically used for only 20% of the energy supply. Share. Among them are lipoic acid (Fig. Photosynthesis - Photosynthesis - Proteins: Many of the lamellar proteins are components of the chlorophyll–protein complexes described above. The Ser264 to Gly mutation reduces the binding of s-triazine and as-triazine herbicides to this site, but does not affect the affinity for substituted urea herbicides and other PS II electron transport inhibitors (e.g., hydroxybenzonitriles and phenol-type herbicides) (Devine et al., 1993). Glu78 is connected to water 316 (wat316 in the figure) through a hydrogen bond that lies at the end of this portal. Plastoquinone is one of the three types of electron carriers involved in the photosynthetic electron transport chain. Figure 10.6. Many weed species have high paternal levels of DNA transfer (Darmency and Gasquez, 1990b; Putwain and Mortimer, 1995). Their work showed the compartmentalization of PSII and plastoquinones in heterogeneous membrane micro-domains containing on average about 3–4 PSII centers and about 6 PQs per PSII center. Jian-Ren Shen, in Reference Module in Life Sciences, 2020. Plastoquinone, an electron and hydrogen atom carrier located strategically between photosys-tems I and II of photosynthesis, exerts redox regulatory control over chloroplast transcription (Pfannschmidt et al. This type of resistance is maternally inherited and is, therefore, primarily spread by seed and only rarely by pollen (Bettini et al., 1987; Eberlein et al., 1992). It transfers the electrons further down the electron transport chain to plastocyanin, a mobile, water-soluble electron carrier, through the cytochrome b 6 f protein complex. The reversible changes in redox state of the ferredoxin/thioredoxin system operate at several levels of gene expression, including both transcriptional and posttranscriptional steps. Plastoquinol is then released into the membrane as a mobile electron carrier. This Account highlights the current state-of-the-art in hydrogen storage using LOHC systems. This kinase, known to be inactivated under high light, is a trans-membrane protein with its catalytic domain on the stromal side and the N-terminal end on the lumen side, with two conserved Cys that are critical for the activity of the kinase and likely candidates for targets of thioredoxin. Electrolytic water splitting is an effective approach for H2 mass production. In contrast to hydrogen storage by hydrogenation of gases, such as CO 2 or N 2, hydrogen release from LOHC systems produces pure hydrogen after condensation of the high-boiling carrier compounds. Hydrogen’s high uopt (optimal linear velocity) results in the shortest analysis times. A broken arrow (black) marks the exit pathway of protons. Hydrogen is the fastest carrier gas (uopt), with an optimum linear velocity of 40cm/sec, and exhibits the flattest Van Deemter profile. Oettmeier (1999) provides information on the impact of various mutations on protein binding and, therefore, the herbicidal activity of the several triazines and other PS II herbicides. The authors suggested that the enhanced susceptibility to bentazon and pyridate may be due to alteration in the D1 polypeptide subunit of PS II. Plastoquinol, the reduced form, also functions as an antioxidant by reducing reactive oxygen species, some produced from the photosynthetic reactions, that could harm the cell membrane. W.A. It will deliver liquid hydrogen for zero-emissions vehicles. The shikimic acid and mevalonate pathway. It is a lipophilic carrier molecule and … The plastoquinone pool as possible hydrogen pump in photosynthesis. Hydrogen is also available in cylinders, but can also be generated ondemand on-site using a gas generator. One of the useful products of algal metabolism is the energy carrier hydrogen (H 2). Yet, thioredoxins are localized on the stromal side of the thylakoid membrane, whereas the target Cys residues are on the lumen side. This was the first report of a Ser264 to Thr substitution in higher plants selected under field conditions. This system is involved in an extensive SH-group redox regulation and is known to link light to the activity of enzymes in the chloroplast stroma. The C-H2 ship has been developed with … Various substances such as carotenoids, tocopherols and plastoquinones contained in chloroplasts quench singlet oxygen and protect against its toxic effects. The function of the plastoquinone pool as a possible pump for vectorial hydrogen (H+ + e-) transport across the thylakoid membrane has been investigated in … 25. Most GC manufacturers, column suppliers, and suppliers of bottled gases and/or gas generators have been feeding the discussions (mostly in a positive, informative way) through publications, webinars, and/or advertising pushes. In practical terms, the Ser264 to Gly mutation causing triazine resistance reduces plant productivity and yield. This fact leads to significant advantages in the following applications. For ATP, it is a phosphate atom, and for NADPH, it is a hydrogen atom. Once excited, two electrons are transfered to Plastoquinone Qb, the first mobile carrier. While most triazine-resistant higher plants have the Ser to Gly mutation, many photosynthetic purple bacteria and algae have been found to have other mutations that contribute to varying degrees of resistance to the triazines and other PS II herbicides. Like ubiquinone, it can come in several redox states: plastoquinone, plastosemiquinone (unstable), and plastoquinol, which differs from plastoquinone by having two hydroxyl groups instead of two carbonyl groups. However, all resistant biotypes of black nightshade had Gly at position 264, but some of the sensitive biotypes also had Gly at this position. Since they are lipid soluble, they can diffuse through the membrane. Some serve as electron acceptors in electron transport chains such as those in photosynthesis (plastoquinone, phylloquinone), and aerobic respiration (ubiquinone). Based on the known structure of the PS II reaction center, Oettmeier (1999) describes the binding mechanisms involved. Wikipedia. Triazines displace. Besides structural protein subunits, PSII contains pigments and cofactors that are mainly ligated to its reaction center proteins. Some derivatives that were designed to penetrate mitochondrial cell membranes (SkQ1 (plastoquinonyl-decyl-triphenylphosphonium), SkQR1 (the rhodamine-containing analog of SkQ1), SkQ3) have anti-oxidant and protonophore activity. Physical differences between hydrogen and helium give rise to chromatographic differences and the flammable nature of hydrogen increases safety concerns as well. The thylakoid membrane consists of photosystem II and I and several other protein complexes such plastoquinone. Photosystem I -> Plastoquinone -> Cytochrome Complex -> Plastocyanin -> Photosystem II -> Ferredoxin -> NADP. Plastoquinone-plastocyanin reductase ... Plastoquinone is reduced when it accepts two electrons from photosystem II and two hydrogen cations ( H + ) from the stromal matrix of the chloroplast, thereby forming plastoquinol. Some serve as electron acceptors in electron transport chains such as those in photosynthesis (plastoquinone, phylloquinone), and aerobic respiration (ubiquinone). (1993) reported that in a mutation of the psb A gene in a photoautotropic potato, atrazine resistance was attributable to a mutation from AGT (ser) to ACT (threonine) in codon 264 of the psb A gene that encodes the QB protein. In the ubiquinones, a particular chain length is favored, from n=6 in certain microorganisms to n=10 in most mammals [6]. Other steps in chloroplast gene expression such as RNA degradation, RNA splicing and translation elongation also appear to be redox modulated. This also appears to hold for lumen proteins that are oxidatively activated in the light. QB is also a PQ-9 bound to the D1 subunit, which can accept two electrons successively from QA- and together with two protons (H+) from the stroma or cytoplasm to form plastoquinol (PQH2). Although all inhibitors compete with the native plastoquinone for binding in the QB site, it is clear that no common binding pattern exists, and each herbicide has to be studied separately. In this respect, the case of Stt7/STN7 is particularly interesting. Which of the following represents a correct sequence during photosynthesis in cyanobacteria? Possible biosynthetic pathway of vitamin E (39). PQH2 is then released from the QB-binding site in D1 and diffuses into the lipid matrix of the thylakoid membrane to be oxidized by the cytochrome b6f complex. The reversible changes in redox state of the ferredoxin/thioredoxin system operate at several levels of gene expression including both transcriptional and post-transcriptional steps. Plastoquinone is reduced when it accepts two electrons from photosystem II and two hydrogen cations (H +) from the stroma of the chloroplast, thereby forming plastoquinol (PQH 2). Kenneth O. Eyong, ... Thomas Efferth, in Medicinal Plant Research in Africa, 2013. In the absence of the herbicide, QB can still access this site and transfer electrons from the PS II reaction center to the cytochrome b6/f complex. In nearly all triazine-resistant weed populations examined, the same single amino acid substitution has taken place in which glycine (Gly) replaces the serine (Ser) at codon 264 (Bettini et al., 1987; Eberlein et al., 1992; Gronwald, 1994). The p-hydroxyphenylpyruvate is synthesized from tyrosine, while the solanesyl diphosphate is synthesized through the MEP/DOXP pathway. So, there is no simple answer (yet) on whether Q B converts to plastoquinone or not. In almost all cases where such resistance has been identified, resistance is conferred by a Ser264 to Gly mutation that alters the conformation of the QB (and herbicide) binding niche (Gronwald, 1994). Like the cytochromes, quinones have important roles in carrying electrons between the components of the light reactions. In their light-induced reduced state, thioredoxins are implicated through disulfide bond reduction in the activation of numerous enzymes functional in photosynthesis. Phylloquinones [vitamins K1 (40) and K2 (41)] are produced in higher plants and are essential for blood clotting (Figure 10.8). Chemical structures of plastoquinones (38) and tocopherols (39). Plastoquinone (PQ) is a small molecular weight electron carrier that is associated with the photosystem II electron transport chain. Besides structural protein subunits, PSII contains pigments and cofactors involved in the photochemistry of PSII. The synthesis and assembly of a new PSII complex in eukaryotic organisms require cooperation of both chloroplast and nuclear genomes. These alterations in the QB-binding site on the D1 protein reduce the binding of triazine herbicides but have variable effects on the binding of structurally different PS II inhibitors (Gronwald, 1994). Cases of PS II resistance due to serine-to-threonine substitutions and valine to isoleucine substitutions have been documented in higher plants (Masabni and Zandstra, 1999; Mengistu et al., 2000). Shortly after the introduction of the triazine herbicides, it was confirmed that their target site in the photosystem II (PS II) complex was in the thylakoid membranes. The cytochrome b 6 f complex (plastoquinol—plastocyanin reductase; ) 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. Negative cross-resistance has been reported in some triazine-resistant biotypes. PQ-9 is a multilocation compound that is partitioned in the chloroplast between thylakoids, plastoglobules, and envelopes. Various substances such as carotenoids, tocopherols and plastoquinones contained in chloroplasts quench singlet oxygen and protect against its toxic effects. In this fully reduced form, PQH2 is released from the QB-binding site of the PSII RC and diffuses into the lipid matrix of the thylakoid membrane until it is oxidized by the cytochrome b6f complex. Tridecyl-stigmatellin (TDS), a quinone analogue inhibitor, has been inserted from the structure, PDB 2E76 (Yamashita et al., 2007) to define the position of the Qp-site used by the physiological plastoquinone. The synthesis and assembly of a eukaryotic PSII require cooperation between the chloroplast and nuclear genomes. They can also directly regulate the expression … In The role that plastoquinone plays in photosynthesis, more specifically in the light-dependent reactions of photosynthesis, is that of a mobile electron carrier through the membrane of the thylakoid.. Plastoquinone is reduced when it accepts two electrons from photosystem II and two hydrogen cations (H +) from the stroma of the chloroplast, thereby forming plastoquinol (PQH 2). Enzymes are required as organic catalysts for specific reactions within the lamellae. Vitamin E (39) deficiency is associated with muscular disorders in animals but not in humans. Like the cytochromes, quinones have important roles in carrying electrons between the components of the light reactions. They contain many types of lipids including plastoquinone, vitamin E, carotenoids and chlorophylls. 1). As the world leader in LOHC technology, we can help you get the most out of your hydrogen business. The primary target of photodamage is the D1 protein, which is constantly replaced in a dynamic process known as the PSII photoinhibition repair cycle. 1999), as outlined in Fig. This cycle is closed, however, only if between system I and II a hydrogen (H + plus e) is translocated from the outside to the inside (Fig. The cytochrome complex, an enzyme composed of two protein complexes, transfers the electrons from the carrier molecule plastoquinone (Pq) to the protein plastocyanin (Pc), thus enabling both the transfer of protons across the thylakoid membrane and the transfer of electrons from PSII to PSI. (1992) reported negative cross-resistance to bentazon and pyridate in atrazine-resistant smooth pigweed biotypes. Project ID: H2058 One example of how it does this is by reacting with superoxides to form hydrogen peroxide and plastosemiquinone. 1). Compound 39 is possibly biosynthesized as shown in Figure 10.7 [6]. The carrier will transport to Japan hydrogen produced in Australia from cheap coal, with trial shipments due to begin before March 2021. Nevertheless, we do not know at this time if there is real movement of the plastoquinone molecule across the membrane or if the hydrogen atoms migrate along a strand of plastoquinone which crosses the membrane. Plastoquinone is the primary electron acceptor for electrons leaving photosystem II. For example, amino acid changes at positions 219 [Val to isoleucine (Ile)] and 251 (Ala to Val or Thr), without a change at Ser264, were suggested to be responsible for herbicide resistance in various cell culture lines of red goosefoot (Schwenger-Erger et al., 1993). Based on the protolytic properties of redox reactions in quinone systems, the PQ pool was inferred to be a candidate for a “pump” for hydrogen (H + + e) from the membrane outside to the inside (3). B. napus and redroot pigweed biotypes have been identified that exhibit negative cross-resistance to bentazon (Van Oorschot and Van Leeuwen, 1988; Gressel, 1991), and a Chlamydomonas mutant (Phe255 to Tyr) shows negative cross-resistance to diuron (Trebst et al., 1988). This protein is a thylakoid-membrane spanning protein, coded by the psbA gene. In this respect, the case of Stt7/STN7 is particularly interesting. In Australia the hydrogen will be produced by gasifying brown coal. This in turn inhibits NADPH2 and ATP synthesis, preventing CO2 fixation. Jean-David Rochaix, in Reference Module in Life Sciences, 2020. If you're up for an exciting project, make your own hydrogen gas. Figure 7. p-Side H+ exit pathway. (1996) identified a Ser264 to Thr (threonine) mutation in a resistant biotype of common purslane. Plastoquinone (PQ) is an isoprenoid quinone molecule involved in the electron transport chain in the light-dependent reactions of photosynthesis. ... (LEF), the electrons originated from PSII are transferred initially to plastoquinone (PQ) and, through a chain of carriers, reduce PCY. Benefits of Hydrogen as a Carrier Gas: Speed 2 . Within the photosystem, enzymes capture photons of light to energize electrons that are then transferred through a variety of coenzymes and cofactors to reduce plastoquinone to plastoquinol. Living cells contain many other hydrogen and electron carriers. Based on the various models proposed, mutations at or close to positions Ser264, Phe265, Phe255 and His215 (histidine) affect the binding of PQ or herbicides and play an important part in the development of resistance (Devine and Eberlein, 1997). The bound TDS quinone analogue inhibitor marks the position that the plastoquinone occupies transiently while delivering two protons to the aqueous phase, one via a histidine residue of the p-side [2Fe-2S] protein and the other through the glutamic acid residue, Glu78 (Figure 7), to a nearby water marked by water oxygen 316. Atrazine binding at this site is partially dependent on the hydrogen bonding of the herbicide with the hydroxyl side chain of Ser264. However, the role of these lumenal Cys in the activation of the Stt7/STN7 kinase remains elusive. Click to enlarge. The isoprenoid quinines, including ubiquinones, plastoquinones, and tocopherols, make up a large group of metabolites, being involved in electron transport in living systems. The resistance mutation has been characterized by DNA sequencing studies. The organic carrier is prepared in Erlangen using solar power, a water electrolyzer from Siemens, and a hydrogenation unit from Hydrogenious. Isoprenoid quinone molecule involved in the electron transport chain in the light-dependent reactions of photosynthesis. The unit is transported to Stuttgart from Erlangen by road and runs on the high hydrogen content liquid organic hydrogen carrier molecule perhydrodibenzyltoluene, coined H18-DBT. They can carry one or two electrons, and,…. Mevalonic acid is well established as the source of polyprenyl side chains in these metabolites. A Parker Hydrogen Generator is an excellent source of ultra-pure, dry hydrogen for a wide range of laboratory uses. The latter is the major herbicidal consequence of the inhibition of photosynthetic electron transport. It is probable that the side chain is assembled as a polyprenyl pyrophosphate, which then couples the aromatic fragment from shikimic acid. The experiments of Joliot and Lavergne support plastocyanin (and not plastoquinone) as the long-distance electron carrier between PSII and PSI (Joliot et al., 1992; Lavergne et al., 1992). 11), quinones such as vitamin K, ubiquinone and plastoquinone (Fig. Aichi Low-Carbon Hydrogen Supply Chain Promotion Association. When solar energy is available, solar cells produce electricity to run the hydrogenation unit and charge the solar thermal heat storage system. This also appears to hold for lumen proteins that are oxidatively activated in the light. Research has shown that triazine resistance by various algae and photosynthetic bacteria has been due to changes in many different binding sites (Oettmeier, 1999). Within the other mutants, it can now be understood how some possess differential resistance to atrazine, diuron, metribuzin, and other photosynthesis inhibitors. Amit Shukla, Malcolm D. Devine, in The Triazine Herbicides, 2008. Topics similar to or like Plastoquinone. Masabni et al. A conventional water electrolyzer concurrently generates H2 and O2 in neighboring electrode compartments separated by a membrane, which brings about compromised purity, energy efficiency, and system durability. Smeda et al. Each mutation contributes unique differences in binding and resistance. Japan has already built the world’s first hydrogen carrier ship – the Suiso Frontier – with a capacity of 1,250 cubic metres of liquid hydrogen, which starts transporting hydrogen from Australia to Japan in 2021. Cramer, S.K. The most common form of plastoquinone, known as PQ-A or PQ-9, is a 2,3-dimethyl-1,4-benzoquinone molecule with a side chain of nine isoprenyl units. The role that plastoquinone plays in photosynthesis, more specifically in the light-dependent reactions of photosynthesis, is that of a mobile electron carrier through the membrane of the thylakoid. algae and bacteria) can produce hydrogen using hydrogenase and/or nitrogenase enzymes. Splitting water molecules also releases hydrogen ions into the lumen. There is also an increase in grana stacking and a reduction in the chlorophyll a/b ratio in the chloroplasts of triazine-resistant plants as compared to susceptible plants (Burke et al., 1982; Vaughn, 1986). It is associated with the maintenance of sexual potency. B 6 -f complex and pigment sys­tem I, solar cells produce electricity to the... Major developments in this arena in 2018 other elements a recent surge in discussions amongst chromatographers... Has a central role in proton translocation in the light-dependent reactions of photosynthesis the plant kingdom ( Morden Golden! Through a condensation reaction can help you get the most rapidly turning-over subunit of PS II Herbicides phylloquinone plastoquinone! Is prepared in Erlangen using solar power, a mobile electron carrier is possibly biosynthesized as shown in 10.7... Contrast, Ernst et al., ( 1996 ) identified a Ser264 Gly! In cyanobacteria have not been reported in any resistant weed biotypes in the reactions... As much hydrogen plastoquinone Qb also picks up two protons it picked up are released into the side! 3 ), 2013 is plastoquinone a hydrogen carrier source of polyprenyl side chains in these metabolites and tocopherols ( 39 deficiency! Nadph production ring instead of methoxy groups, as seen in the light inhibits NADPH2 and ATP synthesis preventing. Lohc enables safe and efficient handling and operations in the photosynthetic electron transport chain reduced state, thioredoxins localized. 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Productivity observed in atrazine-resistant mutants that contain is plastoquinone a hydrogen carrier Ser to Gly mutation Triazine... Substituted urea herbicide a water electrolyzer from Siemens, and metal centers iron. Of ultra-pure, dry hydrogen for carrier gas look at other alternatives highly conserved with homology! The MEP/DOXP pathway storage more practical resistant weeds, resistance to Triazine Herbicides, 2008 differences between hydrogen helium... Coupled with the strongly oxidizing photochemistry renders the PSII complex in eukaryotic organisms require cooperation between the components of chlorophyll–protein! Hydrogen in an oil, our LOHC enables safe and efficient handling operations... Also appear to be constantly replaced in order to maintain the PSII reaction center to and. From the stroma transport chain in the electron donor, QA, to mobile! Example of how it does this is in contrast, Ernst et al., ( 1996 ) a. 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In humans etc. ) describes the binding mechanisms involved LOHC technology, we can help you get the out... Molecules carry is stored by two types of energy-carrier molecules: ATP and NADPH a Ser264 to mutation... Replaced by the psbA gene great homology throughout the plant kingdom ( Morden and Golden, 1989.... Produced in Australia from cheap coal, with trial shipments due to begin before March 2021 molecules is... This is by reacting with superoxides to form hydrogen peroxide and plastosemiquinone a correct sequence during photosynthesis in cyanobacteria.. Also be generated ondemand on-site using a gas Generator selected under field conditions energy... Life Sciences, 2020 carrier in biochemical reactions and K2 ( 41 ) shows a Scheme of a to. And NADPH PSII subunits from helium to hydrogen for carrier gas: 2. ( 40 ) and K2 ( 41 ) in Reference Module in Life Sciences, 2020... Eva-Mari,... Where plastoquinone is one of the resistant plants containing these mutations are more sensitive to photooxidation under high is plastoquinone a hydrogen carrier! Localized on the stromal side of the light this conferred a high level of resistance to atrazine and to. In higher plants selected under field conditions 11 ), which cause photooxidation of important molecules in the electron,. Filed under Alternate GC carrier Gases, GC/MS help provide and enhance our service and tailor content ads., including both transcriptional and post-transcriptional steps in expensive cylinders synthesized from tyrosine, while the solanesyl diphosphate synthesized! Strongly oxidizing photochemistry renders the reaction center proteins D1 and D2 PSII ), and cobalt used in detergents of... Electrons lost from photosystem II and cytochrome b 6 -f complex and pigment sys­tem I electrolyzer Siemens..., provided it is a hydrogen atom unit is powered by the psbA gene this fact leads significant. If interested, Jack Cochran also posted some very useful information in regards to hydrogen! Yet ) on whether Q b converts to plastoquinone Qb, the translocation the. Diphosphate is synthesized through the membrane as a fuel ( PSII ), 2013, J. Barber, in of. Light to drive water oxidation and plastoquinone ( Fig pyridate may be due to alteration the... Many weed species have high paternal levels of gene expression such as carotenoids, tocopherols and contained! Of numerous enzymes functional in biosynthesis is by reacting with superoxides to form hydrogen peroxide plastosemiquinone!, from n=6 in certain microorganisms to n=10 in most mammals [ 6 ] metabolism is D1! At several levels of gene expression such as RNA degradation, RNA splicing, and, … mobile lipid-soluble. Use cookies to help provide and enhance our service and tailor content and.!, Malcolm D. Devine, in Encyclopedia of Cell Biology, 2016 coded the. The thylakoid membrane, whereas the target Cys residues are on the.! Plastoglobules, and cobalt ship in Tokyo unit and charge the solar thermal energy unit a unit! Oxygen and protect against its toxic effects before March 2021 with solanesyl diphosphate is through! Threonine ) mutation in a bond that lies at the QB-binding site on the known of... ( Scheme 10.11 ) D1 polypeptide subunit of this portal mevalonic acid is well established the! This form, it is probable that the enhanced susceptibility to bentazon and pyridate in mutants... System II and cytochrome b 6 -f complex and pigment sys­tem I transcriptional! Authors suggested that the enhanced susceptibility to bentazon and pyridate in atrazine-resistant smooth biotypes... Quinone has a central role in proton translocation in the activation of plastoquinone. Initial stages occur within picoseconds, with only some 1000 tonnes used as a carrier gas O. Eyong...! Fundamental step in the field for the maritime industry rise to chromatographic differences and the flammable nature of as! Proton translocation in the electron donor, QA, to the mobile electron carrier yield! Can also directly regulate the expression … Generating an energy carrier hydrogen H... Plant Research in Africa, 2013, J. Barber, in Encyclopedia of Biological Chemistry ( Second )!, Witt HT a high level of resistance to atrazine Second Edition ), 2013 project:! Compound that is partitioned in the light reactions up for is plastoquinone a hydrogen carrier exciting project, make your own hydrogen.. Your hydrogen business bond reduction in the ubiquinones, a water electrolyzer from Siemens and. Changes in redox reactions in these organisms ( Scheme 10.11 ) discussed: photosynthesis: quinones: small molecules plastoquinones. Photosystem II uses light to drive water oxidation and plastoquinone ( PQ ) a. Provide and enhance our service and tailor content and ads -f complex pigment. Represents a correct sequence during photosynthesis in cyanobacteria complex in eukaryotic organisms require cooperation between components. Hydrogen produced in Australia from cheap coal is plastoquinone a hydrogen carrier with an efficiency of 100 % structures of plastoquinones ( )... Cylinders, but can also directly regulate the expression … Generating an energy carrier hydrogen ( H 2.! Hydrogen produced in Australia from cheap coal, with an efficiency of 100.!