40 Result(s)
within
Article
Klaas J. Hellingwerf
English
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Article
Open AccessConfinement in crystal lattice alters entire photocycle pathway of the Photoactive Yellow Protein
Femtosecond time-resolved crystallography (TRC) on proteins enables resolving the spatial structure of short-lived photocycle intermediates. An open question is whether confinement and lower hydration of the p...
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Open AccessUsing osmotic stress to stabilize mannitol production in Synechocystis sp. PCC6803
Mannitol is a C(6) polyol that is used in the food and medical sector as a sweetener and antioxidant, respectively. The sustainable production of mannitol, especially via the direct conversion of CO2 by photosynt...
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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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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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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
Open AccessDesign, characterization and in vivo functioning of a light-dependent histidine protein kinase in the yeast Saccharomyces cerevisiae
Helical alignment of the α-helical linker of the LOV (light-oxygen-voltage) domain of YtvA from Bacillus subtilis with the α-helical linker of the histidine-protein kinase domain of the Sln1 kinase of the phospho...
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Open AccessAlignment of microbial fitness with engineered product formation: obligatory coupling between acetate production and photoautotrophic growth
Microbial bioengineering has the potential to become a key contributor to the future development of human society by providing sustainable, novel, and cost-effective production pipelines. However, the sustaine...
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Open AccessEthylene production with engineered Synechocystis sp PCC 6803 strains
Metabolic engineering and synthetic biology of cyanobacteria offer a promising sustainable alternative approach for fossil-based ethylene production, by using sunlight via oxygenic photosynthesis, to convert c...
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Open AccessGenetic engineering of Synechocystis PCC6803 for the photoautotrophic production of the sweetener erythritol
Erythritol is a polyol that is used in the food and beverage industry. Due to its non-caloric and non-cariogenic properties, the popularity of this sweetener is increasing. Large scale production of erythritol...
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Open AccessSingle-cell screening of photosynthetic growth and lactate production by cyanobacteria
Photosynthetic cyanobacteria are attractive for a range of biotechnological applications including biofuel production. However, due to slow growth, screening of mutant libraries using microtiter plates is not ...
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Open AccessQuantitative proteomics analysis of an ethanol- and a lactate-producing mutant strain of Synechocystis sp. PCC6803
This study aimed at exploring the molecular physiological consequences of a major redirection of carbon flow in so-called cyanobacterial cell factories: quantitative whole-cell proteomics analyses were carried...
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Open AccessExploring metabolic engineering design principles for the photosynthetic production of lactic acid by Synechocystis sp. PCC6803
Molecular engineering of the intermediary physiology of cyanobacteria has become important for the sustainable production of biofuels and commodity compounds from CO2 and sunlight by “designer microbes.” The chem...
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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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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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Open AccessAlgal Photosynthesis as the Primary Driver for a Sustainable Development in Energy, Feed, and Food Production
High oil prices and global warming that accompany the use of fossil fuels are an incentive to find alternative forms of energy supply. Photosynthetic biofuel production represents one of these since for this, ...
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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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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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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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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 ...
