Dispensability of a sulfolipid for photoautotrophic cell growth and photosynthesis in a marine cyanobacterium, Synechococcus sp. PCC 7002

Sato, Norihiro; Kamimura, Ryohei; Tsuzuki, Mikio

doi:10.1016/j.bbrc.2016.06.148

Cited by 9 publications

(8 citation statements)

References 30 publications

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“…The slight effects of SQDG absence on PSII activity observed in the thermophilic cyanobacterium in the present and previous studies (3) are similar to those observed with other organisms (except Synechocystis 6803) and may be taken as evidence to indicate that SQDG is dispensable for the photosynthetic growth and PSII activity (13). However, our structural analysis of the ⌬sqdB mutant PSII clearly showed that all of the four SQDG-binding sites have been occupied by other lipid molecules.…”

Section: Discussionsupporting

confidence: 88%

“…In Arabidopsis thaliana and two species of cyanobacteria (Synechococcus elongatus PCC 7942 and a marine cyanobacterium Synechococcus sp. PCC 7002), inactivation of the genes for SQDG synthesis resulted in very little effects on their growth, oxygen-evolving activity, and the sensitivity to herbicides such as 3-(3,4-dichlorophenyl)-1, 1-dimethylurea (DCMU) under normal growth conditions (11)(12)(13). The effects of inactivation of the gene for SQDG synthesis, however, became much more severe under PG-limiting conditions caused by phosphate (P i ) deficiency or by genetic disruption of the PG biosynthesis pathway (3,11,14).…”

Section: Sulfoquinovosyl-diacylglycerol (Sqdg) Is One Of the Four Lipmentioning

confidence: 99%

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Thylakoid membrane lipid sulfoquinovosyl-diacylglycerol (SQDG) is required for full functioning of photosystem II in Thermosynechococcus elongatus

Nakajima

Umena

Nagao

et al. 2018

Journal of Biological Chemistry

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Sulfoquinovosyl-diacylglycerol (SQDG) is one of the four lipids present in the thylakoid membranes. Depletion of SQDG causes different degrees of effects on photosynthetic growth and activities in different organisms. Four SQDG molecules bind to each monomer of photosystem II (PSII), but their role in PSII function has not been characterized in detail, and no PSII structure without SQDG has been reported. We analyzed the activities of PSII from an SQDG-deficient mutant of the cyanobacterium by various spectroscopic methods, which showed that depletion of SQDG partially impaired the PSII activity by impairing secondary quinone (Q) exchange at the acceptor site. We further solved the crystal structure of the PSII dimer from the SQDG deletion mutant at 2.1 Å resolution and found that all of the four SQDG-binding sites were occupied by other lipids, most likely PG molecules. Replacement of SQDG at a site near the head of Q provides a possible explanation for the Q impairment. The replacement of two SQDGs located at the monomer-monomer interface by other lipids decreased the stability of the PSII dimer, resulting in an increase in the amount of PSII monomer in the mutant. The present results thus suggest that although SQDG binding in all of the PSII-binding sites is necessary to fully maintain the activity and stability of PSII, replacement of SQDG by other lipids can partially compensate for their functions.

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Section: Discussionsupporting

confidence: 88%

Section: Sulfoquinovosyl-diacylglycerol (Sqdg) Is One Of the Four Lipmentioning

confidence: 99%

Thylakoid membrane lipid sulfoquinovosyl-diacylglycerol (SQDG) is required for full functioning of photosystem II in Thermosynechococcus elongatus

Nakajima

Umena

Nagao

et al. 2018

Journal of Biological Chemistry

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“…kessleri 11h [22], the wild types of Synechocystis and Synechococcus , and the two disruptants of Synechococcus as to the sqdB and sqdX genes [21, 23]. The culture media for normal growth were 5-fold diluted Gamborg’s B5 [24] and BG11 [23] for C .…”

Section: Methodsmentioning

confidence: 99%

“…Also, disruptants of Synechococcus as to the sqdB and sqdX genes (Δ sqdB and Δ sqdX , respectively; [21]) were characterized as to the behavior of cells for acclimation to S-starvation stress to determine the physiological significance of SQDG synthesis. Obtained results will be discussed from an evolutionary aspect for oxygenic photosynthetic organisms.…”

Section: Introductionmentioning

confidence: 99%

Species-specific roles of sulfolipid metabolism in acclimation of photosynthetic microbes to sulfur-starvation stress

et al. 2017

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Photosynthetic organisms utilize sulfate for the synthesis of sulfur-compounds including proteins and a sulfolipid, sulfoquinovosyl diacylglycerol. Upon ambient deficiency in sulfate, cells of a green alga, Chlamydomonas reinhardtii, degrade the chloroplast membrane sulfolipid to ensure an intracellular-sulfur source for necessary protein synthesis. Here, the effects of sulfate-starvation on the sulfolipid stability were investigated in another green alga, Chlorella kessleri, and two cyanobacteria, Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942. The results showed that sulfolipid degradation was induced only in C. kessleri, raising the possibility that this degradation ability was obtained not by cyanobacteria, but by eukaryotic algae during the evolution of photosynthetic organisms. Meanwhile, Synechococcus disruptants concerning sqdB and sqdX genes, which are involved in successive reactions in the sulfolipid synthesis pathway, were respectively characterized in cellular response to sulfate-starvation. Phycobilisome degradation intrinsic to Synechococcus, but not to Synechocystis, and cell growth under sulfate-starved conditions were repressed in the sqdB and sqdX disruptants, respectively, relative to in the wild type. Their distinct phenotypes, despite the common loss of the sulfolipid, inferred specific roles of sqdB and sqdX. This study demonstrated that sulfolipid metabolism might have been developed to enable species- or cyanobacterial-strain dependent processes for acclimation to sulfate-starvation.

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“…The PCR product was ligated to the pGEM T-EASY vector (Promega), cut with both BamHI and HindIII for 0.8 kbp deletion in the ORF, and then blunt-ended. The linear DNA obtained was ligated with the kanamycin-resistant gene in pKMT903 (constructed from the transposon Tn903 [ 19 ], a kind gift from Dr. K. Okada, Tokyo University of Pharmacy and Life Sciences) for generation of a plasmid to disrupt the ORF, which was then used for natural transformation in Synechococcus 7002 [ 15 ]. Briefly, Synechococcus 7002 cells were grown to OD 730 of ca.…”

Section: Methodsmentioning

confidence: 99%

Plastoquinone Lipids: Their Synthesis via a Bifunctional Gene and Physiological Function in a Euryhaline Cyanobacterium, Synechococcus sp. PCC 7002

et al. 2023

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Eukaryotic photosynthetic organisms synthesize triacylglycerols, which are crucial physiologically as major carbon and energy storage compounds and commercially as food oils and raw materials for carbon-neutral biofuel production. TLC analysis has revealed triacylglycerols are present in several cyanobacteria. However, mass spectrometric analysis has shown that freshwater cyanobacterium, Synechocystis sp. PCC 6803, contains plastoquinone-B and acyl plastoquinol with triacylglycerol-like TLC mobility, concomitantly with the absence of triacylglycerol. Synechocystis contains slr2103, which is responsible for the bifunctional synthesis of plastoquinone-B and acyl plastoquinol and also for NaCl-stress acclimatizing cell growth. However, information is limited on the taxonomical distribution of these plastoquinone lipids, and their synthesis genes and physiological roles in cyanobacteria. In this study, a euryhaline cyanobacterium, Synechococcus sp. PCC 7002, shows the same plastoquinone lipids as those in Synechocystis, although the levels are much lower than in Synechocystis, triacylglycerol being absent. Furthermore, through an analysis of a disruptant to the homolog of slr2103 in Synechococcus, it is found that the slr2103 homolog in Synechococcus, similar to slr2103 in Synechocystis, contributes bifunctionally to the synthesis of plastoquinone-B and acyl plastoquinol; however, the extent of the contribution of the homolog gene to NaCl acclimatization is smaller than that of slr2103 in Synechocystis. These observations suggest strain- or ecoregion-dependent development of the physiological roles of plastoquinone lipids in cyanobacteria and show the necessity to re-evaluate previously identified cyanobacterial triacylglycerol through TLC analysis with mass spectrometric techniques.

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Dispensability of a sulfolipid for photoautotrophic cell growth and photosynthesis in a marine cyanobacterium, Synechococcus sp. PCC 7002

Cited by 9 publications

References 30 publications

Thylakoid membrane lipid sulfoquinovosyl-diacylglycerol (SQDG) is required for full functioning of photosystem II in Thermosynechococcus elongatus

Thylakoid membrane lipid sulfoquinovosyl-diacylglycerol (SQDG) is required for full functioning of photosystem II in Thermosynechococcus elongatus

Species-specific roles of sulfolipid metabolism in acclimation of photosynthetic microbes to sulfur-starvation stress

Plastoquinone Lipids: Their Synthesis via a Bifunctional Gene and Physiological Function in a Euryhaline Cyanobacterium, Synechococcus sp. PCC 7002

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