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- Chen, Gefei, et al.
(författare)
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Bri2 BRICHOS client specificity and chaperone activity are governed by assembly state
- 2017
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- . Protein misfolding and aggregation is increasingly being recognized as a cause of disease. In Alzheimer's disease the amyloid-beta peptide (A beta) misfolds into neurotoxic oligomers and assembles into amyloid fibrils. The Bri2 protein associated with Familial British and Danish dementias contains a BRICHOS domain, which reduces A beta fibrillization as well as neurotoxicity in vitro and in a Drosophila model, but also rescues proteins from irreversible nonfibrillar aggregation. How these different activities are mediated is not known. Here we show that Bri2 BRICHOS monomers potently prevent neuronal network toxicity of A beta, while dimers strongly suppress A beta fibril formation. The dimers assemble into high-molecular-weight oligomers with an apparent two-fold symmetry, which are efficient inhibitors of non-fibrillar protein aggregation. These results indicate that Bri2 BRICHOS affects qualitatively different aspects of protein misfolding and toxicity via different quaternary structures, suggesting a means to generate molecular chaperone diversity.
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| 2. |
- Sarr, Medoune, et al.
(författare)
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A spidroin-derived solubility tag enables controlled aggregation of a designed amyloid protein
- 2018
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Ingår i: The FEBS Journal. - : WILEY. - 1742-464X .- 1742-4658. ; 285:10, s. 1873-1885
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Tidskriftsartikel (refereegranskat)abstract
- Amyloidogenesis is associated with more than 30 diseases, but the molecular mechanisms involved in cell toxicity and fibril formation remain largely unknown. The inherent tendency of amyloid-forming proteins to aggregate renders expression, purification, and experimental studies challenging. NT* is a solubility tag derived from a spider silk protein that was recently introduced for the production of several aggregation-prone peptides and proteins at high yields. Herein, we investigate whether fusion to NT* can prevent amyloid fibril formation and enable controlled aggregation for experimental studies. As an example of an amyloidogenic protein, we chose the de novo-designed polypeptide 17. The fusion protein NT*-17 was recombinantly expressed in Escherichia coli to produce high amounts of soluble and mostly monomeric protein. Structural analysis showed that 17 is kept in a largely unstructured conformation in fusion with NT*. After proteolytic release, 17 adopts a -sheet conformation in a pH- and salt-dependent manner and assembles into amyloid-like fibrils. The ability of NT* to prevent premature aggregation and to enable structural studies of prefibrillar states may facilitate investigation of proteins involved in amyloid diseases.
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