Differing involvement of sulfoquinovosyl diacylglycerol in photosystem II in two species of unicellular cyanobacteria

Aoki, Motohide; Sato, Norihiro; Meguro, Ayano; Tsuzuki, Mikio

doi:10.1111/j.1432-1033.2003.03970.x

Cited by 82 publications

(65 citation statements)

References 34 publications

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“…Whereas DGDG is essential in Synechococcus but not in Synechocystis, the reverse is true for the requirement of SQDG-the other glycolipid in thylakoid membranes. This anionic glycolipid is essential in Synechocystis (Aoki et al, 2004), whereas the genes required for SQDG synthesis can be knocked out in Synechococcus without effect under optimal conditions (Güler et al, 1996(Güler et al, , 2000. The…”

Section: Physiological Functions Of Dgdg In Thylakoid Membranesmentioning

confidence: 99%

Configuration of the sugar head of glycolipids in thylakoid membranes

Apdila

Awai

2017

Genes Genet. Syst.

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Glycolipids constitute the majority of membrane components in oxygenic photosynthetic organisms, whereas they are minor lipids in other organisms. In cyanobacteria, three glycolipids comprise ~90 mol% of the total lipids in thylakoid membranes, where photosynthetic electron transport occurs. Among these glycolipids, 80 mol% are galactolipids (monogalactosyldiacylglycerol and digalactosyldiacylglycerol). Galactolipids are well conserved in oxygenic photosynthetic organisms and are believed to be essential for the integrity of the membrane system. It remains unclear, however, which part(s) of the galactolipid structure is the key factor for their function, e.g., the sugar moiety and/or the anomeric configuration. To address this issue, several bacterial membrane glycolipid synthase genes have been introduced into cyanobacteria to test for complementation of knocked-out genes involved in galactolipid biosynthesis. In this review, we summarize recent advances in the analyses of sugar species and configurations of glycolipids heterologously synthesized in the thylakoid membrane and discuss their functional importance.4

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Section: Physiological Functions Of Dgdg In Thylakoid Membranesmentioning

confidence: 99%

Configuration of the sugar head of glycolipids in thylakoid membranes

Apdila

Awai

2017

Genes Genet. Syst.

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“…PCC7942 (Gü ler et al, 1996), Synechocystis sp. PCC6803 (Aoki et al, 2004), Chlamydomonas reinhardtii (Sato et al, 1995), and Arabidopsis (Arabidopsis thaliana; Yu et al, 2002), and roles of SQDG in photosynthesis have been studied with these mutants. An analysis of the mutants indicated that the level of responsibility of SQDG for photosynthesis differed among the organisms.…”

mentioning

confidence: 99%

Digalactosyldiacylglycerol Is Required for Stabilization of the Oxygen-Evolving Complex in Photosystem II

Sakurai¹,

Mizusawa²,

Wada³

et al. 2007

Plant Physiol.

128

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The galactolipid digalactosyldiacylglycerol (DGDG) is present in the thylakoid membranes of oxygenic photosynthetic organisms such as higher plants and cyanobacteria. Recent x-ray crystallographic analysis of protein-cofactor supercomplexes in thylakoid membranes revealed that DGDG molecules are present in the photosystem II (PSII) complex (four molecules per monomer), suggesting that DGDG molecules play important roles in folding and assembly of subunits in the PSII complex. However, the specific role of DGDG in PSII has not been fully clarified. In this study, we identified the dgdA gene (slr1508, a ycf82 homolog) of Synechocystis sp. PCC6803 that presumably encodes a DGDG synthase involved in the biosynthesis of DGDG by comparison of genomic sequence data. Disruption of the dgdA gene resulted in a mutant defective in DGDG synthesis. Despite the lack of DGDG, the mutant cells grew as rapidly as the wild-type cells, indicating that DGDG is not essential for growth in Synechocystis. However, we found that oxygen-evolving activity of PSII was significantly decreased in the mutant. Analyses of the PSII complex purified from the mutant cells indicated that the extrinsic proteins PsbU, PsbV, and PsbO, which stabilize the oxygen-evolving complex, were substantially dissociated from the PSII complex. In addition, we found that heat susceptibility but not dark-induced inactivation of oxygen-evolving activity was notably increased in the mutant cells in comparison to the wild-type cells, suggesting that the PsbU subunit is dissociated from the PSII complex even in vivo. These results demonstrate that DGDG plays important roles in PSII through the binding of extrinsic proteins required for stabilization of the oxygen-evolving complex.

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“…It has been thought that photosynthetic organisms require constant anionic lipid content by keeping a certain total level of PG and SQDG; if necessary, the two anionic lipids could substitute for each other to some extent, such that the photosynthetic apparatus can function properly and normally. It was found that several photosynthetic organisms, depending on available sources of nutrition, could reciprocally adjust the PG and SQDG contents and maintain the level of the sum of these anionic lipids (Benning et al, 1993;Sato et al, 1995;Guler et al, 1996;Essigmann et al, 1998;Yu et al, 2002;Aoki et al, 2004). However, the increased SQDG in this pgpB mutant could not recover its decreased CO 2 -dependent photosynthetic activity and DCBQ-dependent PSII activity, suggesting the different role for PG and SQDG in maintenance of thylakoid properties in Anabaena sp.…”

Section: Parametersmentioning

confidence: 82%

“…However, the increased SQDG in this pgpB mutant could not recover its decreased CO 2 -dependent photosynthetic activity and DCBQ-dependent PSII activity, suggesting the different role for PG and SQDG in maintenance of thylakoid properties in Anabaena sp. PCC7120, as suggested by Aoki et al (2004).…”

Section: Parametersmentioning

confidence: 99%

Impaired Photosynthesis in Phosphatidylglycerol-Deficient Mutant of Cyanobacterium Anabaena sp. PCC7120 with a Disrupted Gene Encoding a Putative Phosphatidylglycerophosphatase

Yang

Kuang

2006

Plant Physiology

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Phosphatidylglycerol (PG) is a ubiquitous phospholipid in thylakoid membranes of cyanobacteria and chloroplasts and plays an important role in the structure and function of photosynthetic membranes. The last step of the PG biosynthesis is dephosphorylation of phosphatidylglycerophosphate (PGP) catalyzed by PGP phosphatase. However, the gene-encoding PGP phosphatase has not been identified and cloned from cyanobacteria or higher plants. In this study, we constructed a PG-deficient mutant from cyanobacterium Anabaena sp. PCC7120 with a disrupted gene (alr1715, a gene for Alr1715 protein, GenBank accession no. BAB78081) encoding a putative PGP phosphatase. The obtained mutant showed an approximately 30% reduction in the cellular content of PG. Following the reduction in the PG content, the photoautotrophical growth of the mutant was restrained, and the cellular content of chlorophyll was decreased. The decreases in net photosynthetic and photosystem II (PSII) activities on a cell basis also occurred in this mutant. Simultaneously, the photochemical efficiency of PSII was considerably declined, and less excitation energy was transferred toward PSII. These findings demonstrate that the alr1715 gene of Anabaena sp. PCC7120 is involved in the biosynthesis of PG and essential for photosynthesis.Thylakoid membranes of cyanobacteria and chloroplasts of plants and algae are the sites of the oxygenic photosynthesis, where highly organized pigmentprotein complexes are embedded in the lipid matrix. Thylakoid membranes are characterized by its unique lipid composition, which is in contrast with animal, bacterial, and nonchloroplastic cell membranes dominated by phospholipids. The major lipids of thylakoid membranes are the uncharged galactolipids, namely, monogalacotsyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG). These galactolipids account for at least 50 mol% of the total thylakoid lipids. In addition, thylakoid membranes are specific in that there is a negatively charged sulfolipid, sulfoquinovosyl diacylglycerol (SQDG), which seems not to be present in nonphotosynthetic organisms. The only significant phospholipid is phosphatidylglycerol (PG), rather than phosphatidylcholine or phosphatidylethnolamine (Murata and Siegenthaler, 1998).PG is an anionic phospholipid that is also extensively distributed in the functional domains of thylakoid membranes, suggesting that PG is critical for the structure and function of thylakoid membrane. Indeed, increasing biochemical and genetic studies provided evidence that PG plays an important role in photosynthesis of thylakoid membranes. It has shown that PG is indispensable for the dimerization of PSII (Kruse et al., 2000) and trimerization of the lightharvesting complex of PSII (Nußberger et al., 1993;Hobe et al., 1994;Liu et al., 2004). PG is also essential for the oligomerization of PSI reaction center of cyanobacterium (Domonkos et al., 2004), consistent with the fact that PG is an integral component of PSI (Jordan et al., 2001). It was found that PG is required for ...

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Differing involvement of sulfoquinovosyl diacylglycerol in photosystem II in two species of unicellular cyanobacteria

Cited by 82 publications

References 34 publications

Configuration of the sugar head of glycolipids in thylakoid membranes

Configuration of the sugar head of glycolipids in thylakoid membranes

Digalactosyldiacylglycerol Is Required for Stabilization of the Oxygen-Evolving Complex in Photosystem II

Impaired Photosynthesis in Phosphatidylglycerol-Deficient Mutant of Cyanobacterium Anabaena sp. PCC7120 with a Disrupted Gene Encoding a Putative Phosphatidylglycerophosphatase

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