34 Result(s)
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Protocol
Development of a Light-Dependent Protein Histidine Kinase
Phosphorylation plays a critical role in facilitating signal transduction in prokaryotic and eukaryotic organisms. Our study introduces a tool for investigation of signal diffusion in a biochemical regulation ...
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Article
Open AccessExploring the low photosynthetic efficiency of cyanobacteria in blue light using a mutant lacking phycobilisomes
The ubiquitous chlorophyll a (Chl a) pigment absorbs both blue and red light. Yet, in contrast to green algae and higher plants, most cyanobacteria have much lower photosynthetic rates in blue than in red light. ...
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Article
Open AccessBlue light reduces photosynthetic efficiency of cyanobacteria through an imbalance between photosystems I and II
Several studies have described that cyanobacteria use blue light less efficiently for photosynthesis than most eukaryotic phototrophs, but comprehensive studies of this phenomenon are lacking. Here, we study t...
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Article
Open AccessSpectrally decomposed dark-to-light transitions in Synechocystis sp. PCC 6803
Photosynthetic activity and respiration share the thylakoid membrane in cyanobacteria. We present a series of spectrally resolved fluorescence experiments where whole cells of the cyanobacterium Synechocystis sp....
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Article
Tryptophan fluorescence as a reporter for structural changes in photoactive yellow protein elicited by photo-activation
Light-activation of photoactive yellow protein (PYP) is followed by a series of dynamical transitions in the structure of the protein. Tryptophan fluorescence is well-suited as a tool to study selected aspects...
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Article
Is the photoactive yellow protein a UV-B/blue light photoreceptor?
UV light below 300 nm is shown to generate the first photocycle intermediate in the blue light photoreceptor Photoactive Yellow Protein. Fluorescence and ultrafast transient absorption measurements indicate tw...
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Chapter
Photoreceptor Proteins from Purple Bacteria
Purple bacteria contain representatives of four of the six main families of photoreceptor proteins: phytochromes, BLUF domain containing proteins, xanthopsins (i.e., photoactive yellow proteins), and phototrop...
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Protocol
Prokaryotic Phototaxis
Microorganisms have various mechanisms at their disposal to react to (changes in) their ambient light climate (i.e., intensity, color, direction, and degree of polarization). Of these, one of the best studied ...
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Article
Binding, tuning and mechanical function of the 4-hydroxy-cinnamic acid chromophore in photoactive yellow protein
The bacterial photoreceptor protein photoactive yellow protein (PYP) covalently binds the chromophore 4-hydroxy coumaric acid, tuning (spectral) characteristics of this cofactor. Here, we study this binding an...
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Chapter
Light-induced behavioral responses (‘phototaxis’) in prokaryotes
Light-induced sensory responses are among the oldest scientific observations on bacterial behavior. Various types of response have been characterized physiologically in detail. However, the molecular basis of ...
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Article
Chromophore composition of a heterologously expressed BLUF-domain
Upon heterologous expression of the BLUF (for: Blue-Light sensing Using Flavin) domain from AppA, a transcriptional anti-repressor from Rhodobacter sphaeroides, in Escherichia coli, photoactive holo-protein is fo...
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Article
Early molecular events in the photoactive yellow protein: role of the chromophore photophysics
We report a comparative study of the isomerization reaction in native and denatured photoactive yellow protein (PYP) and in various chromophore analogues in their trans deprotonated form. The excited-state relaxa...
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Article
Tryptophan fluorescence monitors structural changes accompanying signalling state formation in the photocycle of photoactive yellow protein
Photoactive yellow protein, a small, water-soluble blue-light absorbing photoreceptor protein from Ectothiorhodospira (Halorhodospira) halophila has a structure with two hydrophobic cores, of which the main one h...
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Article
Light-induced behavioral responses (`phototaxis') in prokaryotes
Light-induced sensory responses are among the oldest scientific observations on bacterial behavior. Various types of response have been characterized physiologically in detail. However, the molecular basis of ...
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Article
Phototransformation of green fluorescent protein with UV and visible light leads to decarboxylation of glutamate 222
Wild type green fluorescent protein (GFP) from Aequorea victoria absorbs predominantly at 398 nm. Illumination with UV (254 nm) or visible (390 nm) light transforms this state (GFP398) into one absorbing at 483 n...
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Article
Alkalispirillum mobile gen. nov., spec. nov., an alkaliphilic non-phototrophic member of the Ectothiorhodospiraceae
From cultures of the anoxygenic phototroph Halorhodospira halophila SL-1, an aerobic, gram-negative spirillum was isolated. This moderately halophilic, alkaliphilic bacterium was motile by means of a single pola...
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Chapter
Sensing of Green Light in Complementary Chromatic Adaptation of the Cyanobacterium Calothrix sp.
Light harvesting is essential for phototrophic organisms. The reaction centers of PS2 and PS1 in cyanobacteria contain chl a, † a ubiquitous pigment that absorbs light in two spectral domains. In the blue, absorp...
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Article
Characterization and transcriptional regulation of the Synechocystis PCC 6803, petH gene, encoding ferredoxin-NADP+ oxidoreductase: involvement of a novel type of divergent operator
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Article
Structural and dynamic changes of photoactive yellow protein during its photocycle in solution
Light irradiation of photoactive yellow protein (PYP) induces a photocycle, in which red-shifted (pR) and blue-shifted (pB) intermediates have been characterized. An NMR study of the long-lived pB intermediate...
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Article
Characterization and transcriptional regulation of the Synechocystis PCC 6803 petH gene, encoding ferredoxin-NADP+ oxidoreductase: involvement of a novel type of divergent operator
The petH gene, encoding ferredoxin-NADP+ oxidoreductase (FNR), has been characterised in the unicellular cyanobacterium Synechocystis PCC 6803. Its product, FNR, was heterologously produced and functionally chara...
