Photosynthetic activities of a thermophilic blue-green alga

Yamaoka, Takashi; Satoh, Kazuhiko; Katoh, Sakae

doi:10.1093/oxfordjournals.pcp.a075684

Cited by 163 publications

(101 citation statements)

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“…The wild-type cells of T. elongatus BP-1 (30) were grown at 55°C under constant light from white fluorescent lamps at 50 mol m Ϫ2 s Ϫ1 (hereafter called LL conditions) in BG-11 liquid medium (hereafter called liquid BG-11 [6]) and on BG-11 agar medium (hereafter called solid BG-11) that contained 1.5% Bacto Agar (Nippon BD, Tokyo, Japan). To permit selection and maintenance of kanamycin-resistant (Km r ) transformants, liquid BG-11 and solid BG-11 were supplemented with kanamycin at final concentrations of 100 and 75 g/ml, respectively.…”

Section: Methodsmentioning

confidence: 99%

Circadian Rhythms in the Thermophilic Cyanobacterium Thermosynechococcus elongatus : Compensation of Period Length over a Wide Temperature Range

et al. 2004

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Proteins derived from the thermophilic cyanobacterium Thermosynechococcus elongatus BP-1, which performs plant-type oxygenic photosynthesis, are suitable for biochemical, biophysical, and X-ray crystallographic studies. We developed an automated bioluminescence real-time monitoring system for the circadian clock in the thermophilic cyanobacterium T. elongatus BP-1 that uses a bacterial luciferase gene set (Xl luxAB) derived from Xenorhabdus luminescens as a bioluminescence reporter gene. A promoter region of the psbA1 gene of T. elongatus was fused to the Xl luxAB gene set and inserted into a specific targeting site in the genome of T. elongatus. The bioluminescence from the cells of the psbA1-reporting strain was measured by an automated monitoring apparatus with photomultiplier tubes. The strain exhibited the circadian rhythms of bioluminescence with a 25-h period length for at least 10 days in constant light and temperature. The rhythms were reset by light-dark cycle, and their period length was almost constant over a wide range of temperatures (30 to 60°C). Theses results indicate that T. elongatus has the circadian clock that is widely temperature compensated.Circadian rhythms are endogenous daily fluctuations in physiological activities that have the following three characteristics: they are sustained under constant conditions with a period length of about 24 h; the phase of the rhythm is reset by environmental cues such as light-dark (LD) cycles and lowhigh temperature cycles; and the period of the rhythm is almost constant at physiological temperatures (5, 26). Thus far, circadian rhythms have been observed only in mesophilic organisms; we have found no reports of circadian rhythms in thermophilic organisms.The clock gene cluster kaiABC generates circadian rhythms in the mesophilic cyanobacterium Synechococcus sp. strain PCC 7942 (hereafter called Synechococcus) (8). KaiA and KaiC proteins regulate the transcription of the kaiBC operon positively and negatively, respectively, and this feedback regulation is important for generating circadian oscillations (8). Kai proteins interact with each other in all possible combinations (9), and KaiA enhances the phosphorylation of KaiC (10,28,29). These mesophilic clock proteins are unstable, however, and their structure and function, their mutual interactions, and their reactions with their substrates in the circadian feedback processes remain unknown.The thermophilic cyanobacteria Thermosynechococcus elongatus (30) and T. vulcanus (13), which were isolated from a Japanese hot spring, grow optimally at ca. 57°C, and their proteins are highly stable. The proteins can be easily purified, characterized for biochemical and biophysical properties, and crystallized. The photosynthetic reaction center protein complexes of photosystems I and II have been X-ray analyzed in T. elongatus (11, 31) and T. vulcanus (12). Recently, we cloned the gene cluster kaiABC from both species (7; T. Uzumaki and M. Ishiura, unpublished data), and both showed high homology with the correspo...

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Section: Methodsmentioning

confidence: 99%

Circadian Rhythms in the Thermophilic Cyanobacterium Thermosynechococcus elongatus : Compensation of Period Length over a Wide Temperature Range

et al. 2004

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“…Cells of Synechococcus elongatus [23] The libraries were constructed in the lambda vector system ZAP Express predigested vector kit (Stratagene) essentially according to the instructions of the supplier. Genomic DNA of cyanobacteria was isolated as described [25] and partially digested with the restriction endonuclease Sau3AI.…”

Section: Strains and Culture Conditionsmentioning

confidence: 99%

Biosynthesis of the cyanobacterial reserve polymer multi‐L‐arginyl‐poly‐L‐aspartic acid (cyanophycin)

Berg

Ziegler

Piotukh

et al. 2000

European Journal of Biochemistry

118

100

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Biosynthesis of the cyanobacterial nitrogen reserve cyanophycin (multi-l-arginyl-poly-l-aspartic acid) is catalysed by cyanophycin synthetase, an enzyme that consists of a single kind of polypeptide. Efficient synthesis of the polymer requires ATP, the constituent amino acids aspartic acid and arginine, and a primer like cyanophycin. Using synthetic peptide primers, the course of the biosynthetic reaction was studied. The following results were obtained: (a) sequence analysis suggests that cyanophycin synthetase has two ATP-binding sites and hence probably two active sites; (b) the enzyme catalyses the formation of cyanophycin-like polymers of 25±30 kDa apparent molecular mass in vitro; (c) primers are elongated at their C-terminus; (d) the constituent amino acids are incorporated stepwise, in the order aspartic acid followed by arginine, into the growing polymer. A mechanism for the cyanophycin synthetase reaction is proposed; (e) the specificity of the enzyme for its amino-acid substrates was also studied. Glutamic acid cannot replace aspartic acid as the acidic amino acid, whereas lysine can replace arginine but is incorporated into cyanophycin at a much lower rate.

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“…Here we report the solution structure of the Ϸ12-kDa KaiCinteracting C-terminal KaiA domain (residues 180-283, henceforth named ThKaiA180C) from the thermophilic cyanobacterium Thermosynechococcus elongatus BP-1 (17), which grows naturally at temperatures Ͼ50°C. The superior thermal stability of this domain compared with the equivalent domain of KaiA from S. elongatus (Fig.…”

mentioning

confidence: 99%

NMR structure of the KaiC-interacting C-terminal domain of KaiA, a circadian clock protein: Implications for KaiA–KaiC interaction

Vakonakis

Sun

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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KaiA is a two-domain circadian clock protein in cyanobacteria, acting as the positive element in a feedback loop that sustains the oscillation. The structure of the N-terminal domain of KaiA is that of a pseudo-receiver, similar to those of bacterial response regulators, which likely interacts with components of the clock-resetting pathway. The C-terminal domain of KaiA is highly conserved among cyanobacteria and enhances the autokinase activity of KaiC. Here we present the NMR structure of the C-terminal domain of KaiA from the thermophilic cyanobacterium Thermosynechococcus elongatus BP-1. This domain adopts a novel all ␣-helical homodimeric structure. Several mutations known to affect the period of the circadian oscillator are shown to be located at an exposed groove near the dimer interface. This NMR structure and a 21-Å-resolution electron microscopy structure of the hexameric KaiC particle allow us to postulate a mode of KaiA-KaiC interaction, in which KaiA binds a linker region connecting two globular KaiC domains.

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Photosynthetic activities of a thermophilic blue-green alga

Cited by 163 publications

References 0 publications

Circadian Rhythms in the Thermophilic Cyanobacterium Thermosynechococcus elongatus : Compensation of Period Length over a Wide Temperature Range

Circadian Rhythms in the Thermophilic Cyanobacterium Thermosynechococcus elongatus : Compensation of Period Length over a Wide Temperature Range

Biosynthesis of the cyanobacterial reserve polymer multi‐L‐arginyl‐poly‐L‐aspartic acid (cyanophycin)

NMR structure of the KaiC-interacting C-terminal domain of KaiA, a circadian clock protein: Implications for KaiA–KaiC interaction

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