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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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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
The molecular basis of sensing and responding to light in microorganisms
Photon absorption in biological signal transfer is mediated by a limited number of photoreceptor families, each characterised by binding of chromophore from a particular class of chemical compounds. Most photo...
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Article
Current topics in signal transduction in bacteria
Among the signal transfer systems in bacteria two types predominate: two-component regulatory systems and quorum sensing systems. Both types of system can mediate signal transfer across the bacterial cell enve...
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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
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...
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Article
Regulation of the expression of thePseudomonas stutzeri recA gene
With the aid ofrecA-lacZ fusion strains, thein vivo regulation of thePseudomonas stutzeri recA gene has been studied. It is shown that expression of this gene can be induced with a variety of DNA damaging agents,...
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Article
Molecular cloning and functional characterization of a recA analog from Pseudomonas stutzeri and construction of a P. stutzeri recA mutant
A recombinant plasmid carrying the Pseudomonas stutzeri recA gene was isolated by complementation of the Escherichia coli recA13 mutation. Subcloning experiments showed that the gene was located on a 1500 bp PvuI...
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Article
The role of the proton motive force and electron flow in light-driven solute transport in Rhodopseudomonas sphaeroides