Publications by authors named "Lars Kjaer"

Alpha-synuclein (α-syn) is a 140 amino acid, intrinsically disordered protein with a potential role in neurotransmitter vesicle release. The protein is natively unfolded under physiological conditions, and is expressed predominantly in neural tissue. α-syn is associated with neuropathological conditions in Parkinson's disease, where the protein misfolds into oligomers and fibrils resulting in aggregates in Lewy bodies.

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Following publication of the original article [1], the author reported that the two curves in the sub-diagram WSR4 in Fig. 2a should be the other way round.

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Background: Plant cell walls participate in all plant-environment interactions. Maintaining cell wall integrity (CWI) during these interactions is essential. This realization led to increased interest in CWI and resulted in knowledge regarding early perception and signalling mechanisms active during CWI maintenance.

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The ability of proteins to aggregate to form well-organized β-sheet rich amyloid fibrils is increasingly viewed as a general if regrettable property of the polypeptide chain. Aggregation leads to diseases such as amyloidosis and neurodegeneration in humans and various mammalian species but is also found in a functional variety in both animals and microbes. However, there are to our knowledge no reports of amyloid formation in plants.

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The intrinsically disordered protein α-synuclein (aSN) forms insoluble aggregates in the brains of Parkinson's disease (PD) patients. Cytotoxicity is attributed to a soluble aSN oligomeric species that permeabilizes membranes significantly more than monomers and fibrils. In humans, the A53T mutation induces early onset PD and increases the level of aSN oligomerization and fibrillation propensity, but Thr53 occurs naturally in aSNs of most animals.

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The Parkinson's disease-associated protein α-synuclein (αSN) is natively unfolded but its structure can be modulated by membranes and surfactants. The opportunistic pathogen Pseudomonas aeruginosa (PA) produces and secretes the biosurfactant rhamnolipid (RL) which modulates bacterial biofilm. Here, we show that monomeric RL enhances the ability of αSN to permeabilize membranes, while micellar RL rapidly induces protein β-sheet structure with a worm-like fibrillary appearance, which cannot seed RL-free fibrillation but transforms into linear fibrils faster than αSN fibrillating on its own.

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Alpha-synuclein (aSN) is a presynaptic protein with a pathological role in Parkinson's disease (PD). The mutants A30P, E46K and A53T are involved in PD early-onset forms. aSN is natively unfolded but can self-assemble to oligomers and fibrils and binds anionic membranes in a helical conformation.

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Cellulose is the most abundant biopolymer in the world, the main load-bearing element in plant cell walls, and represents a major sink for carbon fixed during photosynthesis. Previous work has shown that photosynthetic activity is partially regulated by carbohydrate sinks. However, the coordination of cellulose biosynthesis with carbohydrate metabolism and photosynthesis is not well understood.

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Monomeric alpha-synuclein (alphaSN), which has no persistent structure in aqueous solution, is known to bind to anionic lipids with a resulting increase in alpha-helix structure. Here we show that at physiological pH and ionic strength, alphaSN incubated with different anionic lipid vesicles undergoes a marked increase in alpha-helical content at a temperature dictated either by the temperature of the lipid phase transition, or (in 1,2-DilauroylSN-Glycero-3-[Phospho-rac-(1-glycerol)] (DLPG), which is fluid down to 0 degrees C) by an intrinsic cold denaturation that occurs around 10-20 degrees C. This structure is subsequently lost in a thermal transition around 60 degrees C.

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