RESUMEN
Ordered, fibrous, self-seeding aggregates of misfolded proteins known as amyloids are associated with important diseases in mammals and control phenotypic traits in fungi. A given protein may adopt multiple amyloid conformations, known as variants or strains, each of which leads to a distinct disease pattern or phenotype. Here, we study the effect of Hofmeister ions on amyloid nucleation and strain generation by the prion domain-containing fragment (Sup35NM) of a yeast protein Sup35p. Strongly hydrated anions (kosmotropes) initiate nucleation quickly and cause rapid fiber elongation, whereas poorly hydrated anions (chaotropes) delay nucleation and mildly affect the elongation rate. For the first time, we demonstrate that kosmotropes favor formation of amyloid strains that are characterized by lower thermostability and higher frangibility in vitro and stronger phenotypic and proliferation patterns effectively in vivo as compared with amyloids formed in chaotropes. These phenomena point to inherent differences in the biochemistry of Hofmeister ions. Our work shows that the ionic composition of a solution not only influences the kinetics of amyloid nucleation but also determines the amyloid strain that is preferentially formed.
Asunto(s)
Amiloide/química , Factores de Terminación de Péptidos/química , Priones/química , Proteínas de Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/química , Amiloide/genética , Amiloide/metabolismo , Factores de Terminación de Péptidos/genética , Factores de Terminación de Péptidos/metabolismo , Priones/genética , Priones/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismoRESUMEN
Headed for a membrane: Continuous, polycrystalline ZIF-90 membranes (picture, left) can be grown at 65 °C from methanolic precursor solutions on nanocrystal-seeded surfaces of poly(amide-imide) macroporous hollow fibers (right). The ZIF-90 membranes exhibit good separation properties for linear over cyclic hydrocarbons, as well as gas permeation selectivities higher than Knudsen values.