Photomovement of the Gliding Cyanobacterium Synechocystis sp. PCC 6803

Choi, Jong-Soon; Chung, Young‐Ho; Moon, Yoon-Jung; Kim, Changhoon; Watanabe, Masakatsu; Song, Pill‐Soon; Joe, Cheol-O; Bogorad, Lawrence; Park, Young Mok

doi:10.1111/j.1751-1097.1999.tb01954.x

Cited by 86 publications

(41 citation statements)

References 30 publications

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“…PixL and PixG form the PixL-PixGH two-component regulatory system involved in positive control of phototaxis in Synechocystis 6803 (Bhaya, 2004). Although Synechococcus 7002 is not apparently motile, the model cyanobacterium Synechocystis 6803 can move on solid surfaces toward light by twitching motility (Choi et al, 1999; Yoshihara and Ikeuchi, 2004). The apparent redox-sensitivity of this two component system regulator suggests it warrants further study.…”

Section: Resultsmentioning

confidence: 99%

Characterization of protein redox dynamics induced during light-to-dark transitions and nutrient limitation in cyanobacteria

et al. 2014

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Protein redox chemistry constitutes a major void in knowledge pertaining to photoautotrophic system regulation and signaling processes. We have employed a chemical biology approach to analyze redox sensitive proteins in live Synechococcus sp. PCC 7002 cells in both light and dark periods, and to understand how cellular redox balance is disrupted during nutrient perturbation. The present work identified 300 putative redox-sensitive proteins that are involved in the generation of reductant, macromolecule synthesis, and carbon flux through central metabolic pathways, and may be involved in cell signaling and response mechanisms. Furthermore, our research suggests that dynamic redox changes in response to specific nutrient limitations, including carbon and nitrogen limitations, contribute to the regulatory changes driven by a shift from light to dark. Taken together, these results contribute to a high-level understanding of post-translational mechanisms regulating flux distributions and suggest potential metabolic engineering targets for redirecting carbon toward biofuel precursors.

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Section: Resultsmentioning

confidence: 99%

Characterization of protein redox dynamics induced during light-to-dark transitions and nutrient limitation in cyanobacteria

et al. 2014

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“…The Deg Proteases Are Needed for Phototaxis-It is well known that Synechocystis exhibits positive phototactic movement (40). This locomotion requires cell appendages termed type IV pili (TFP), which are also responsible for natural transformation competency (41,42).…”

Section: Growth Characteristics Of the Deg Mutants At High And Lowmentioning

confidence: 99%

The Deg Proteases Protect Synechocystis sp. PCC 6803 during Heat and Light Stresses but Are Not Essential for Removal of Damaged D1 Protein during the Photosystem Two Repair Cycle

Barker

Vries

Nield

et al. 2006

Journal of Biological Chemistry

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Members of the DegP/HtrA (or Deg) family of proteases are found widely in nature and play an important role in the proteolysis of misfolded and damaged proteins. As yet, their physiological role in oxygenic photosynthetic organisms is unclear, although it has been widely speculated that they participate in the degradation of the photodamaged D1 subunit in the photosystem two complex (PSII) repair cycle, which is needed to maintain PSII activity in both cyanobacteria and chloroplasts. We have examined the role of the three Deg proteases found in the cyanobacterium Synechocystis sp. PCC 6803 through analysis of double and triple insertion mutants. We have discovered that these proteases show overlap in function and are involved in a number of key physiological responses ranging from protection against light and heat stresses to phototaxis. In previous work, we concluded that the Deg proteases played either a direct or an indirect role in PSII repair in a glucose-tolerant version of An inevitable consequence of the light reactions of oxygenic photosynthesis is the formation of highly reactive molecules, such as reactive oxygen species (ROS) 5 and amino acid free radicals, which can cause irreversible damage to a variety of cellular components including nucleic acids, lipids, pigments, and proteins (1, 2). The photosystem two complex (PSII), which functions as the light-driven water:plastoquinone oxidoreductase in oxygenic photosynthetic electron transport, is particularly prone to light-induced damage (3). Of the more than 25 protein subunits found in PSII, the D1 reaction center subunit appears to be the major target for photodamage (4 -6). To maintain activity, a damaged PSII complex is repaired through the specific replacement of the damaged subunit (usually D1) by a newly synthesized subunit (3). Despite the importance of the PSII repair cycle for maintaining optimal photosynthetic rates in vivo, the molecular details of this repair process remain unclear.Recently, attention has focused on the identity of the proteases that are involved in removing damaged D1 from the PSII complex. In the case of chloroplasts, in vitro experiments suggest that D1 degradation occurs in a two-step process involving the participation of two classes of protease (7). First, a member of the DegP/HtrA family of proteases (or Deg proteases), originally designated DegP2 but now renamed Deg2 (8), is thought to cleave damaged D1 between trans-membrane helices four and five on the stromal side of the membrane to generate N-terminal and C-terminal fragments of ϳ23 and 10 kDa, respectively. Subsequently, the 23-kDa fragment, and possibly the 10-kDa fragment, is removed from the membrane by one or more members of the FtsH protease family (9).Selective D1 degradation also occurs in cyanobacteria such as Synechocystis sp. PCC 6803 (10). Analysis of the genome sequence of Synechocystis sp. PCC 6803 has identified three members of the Deg proteases and four members of the FtsH family of proteases (11). Mutagenesis experiments have so far demonstr...

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“…The enzymatic activities are regulated in a red and far-red lightdependent manner in a similar way as has been recently demonstrated for the serine/threonine kinase activity of plant phytochromes (8,9). In addition, the Cph1 protein has been implicated as the photosensor for the photomovement of Synechocystis (10). While physiological roles of the Cph1 is yet unknown, it is likely that the Cph1 is a photosensor protein acting in conjunction with the Rcp1 regulator, as a two-component signaling system similar to the bacterial binary sensory systems (5).…”

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confidence: 99%

Chromophore−Apoprotein Interactions in Synechocystis sp. PCC6803 Phytochrome Cph1

et al. 2000

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The secondary, tertiary, and quaternary structures of the Synechocystis Cph1 phytochrome were investigated by absorption and circular dichroism spectroscopy, size exclusion chromatography, and limited proteolysis. The Cph1 protein was coexpressed with a bacterial thioredoxin in Escherichia coli, reconstituted in vitro with tetrapyrrole chromophores, and purified by chitin affinity chromatography. The resultant Cph1 holoproteins were essentially pure and had the specific absorbance ratio (SAR) of 0.8-0.9. Circular dichroism spectroscopy and limited proteolysis showed that the chromophore binding induced marked conformational changes in the Cph1 protein. The alpha-helical content increased to 42-44% in the holoproteins from 37% in the apoprotein. However, no significant difference in the secondary structure was detected between the Pr and Pfr forms. The tertiary structure of the Cph1 apoprotein appeared to be relatively flexible but became more compact and resistant to tryptic digestion upon chromophore binding. Interestingly, a small chromopeptide of about 30 kDa was still predominant even after longer tryptic digestion. The N-terminal location of this chromopeptide was confirmed by expression in E. coli and in vitro reconstitution with chromophores of the 32.5 kDa N-terminal fragment of the Cph1 protein. This chromopeptide was fully photoreversible with the spectral characteristic similar to that of the full-size Cph1 protein. The Cph1 protein forms dimers through the C-terminal region. These results suggest that the prokaryotic Cph1 phytochrome shares the structural and conformational characteristics of plant phytochromes, such as the two-domain structure consisting of the relatively compact N-terminal and the relatively flexible C-terminal regions, in addition to the chromophore-induced conformational changes.

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Photomovement of the Gliding Cyanobacterium Synechocystis sp. PCC 6803

Cited by 86 publications

References 30 publications

Characterization of protein redox dynamics induced during light-to-dark transitions and nutrient limitation in cyanobacteria

Characterization of protein redox dynamics induced during light-to-dark transitions and nutrient limitation in cyanobacteria

The Deg Proteases Protect Synechocystis sp. PCC 6803 during Heat and Light Stresses but Are Not Essential for Removal of Damaged D1 Protein during the Photosystem Two Repair Cycle

Chromophore−Apoprotein Interactions in Synechocystis sp. PCC6803 Phytochrome Cph1

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