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Polymorphism of amyloid-like fibrils can be defined by the concentration of seeds.

Sneideris T, Milto K, Smirnovas V - PeerJ (2015)

Bottom Line: The strains are enciphered by different misfolded conformations.Strain-like phenomena have also been reported in a number of other amyloid-forming proteins.Our findings could explain conformational switching between amyloid strains observed in a wide variety of in vivo and in vitro experiments.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biothermodynamics and Drug Design, Vilnius University, Institute of Biotechnology , Vilnius , Lithuania.

ABSTRACT
Prions are infectious proteins where the same protein may express distinct strains. The strains are enciphered by different misfolded conformations. Strain-like phenomena have also been reported in a number of other amyloid-forming proteins. One of the features of amyloid strains is the ability to self-propagate, maintaining a constant set of physical properties despite being propagated under conditions different from those that allowed initial formation of the strain. Here we report a cross-seeding experiment using strains formed under different conditions. Using high concentrations of seeds results in rapid elongation and new fibrils preserve the properties of the seeding fibrils. At low seed concentrations, secondary nucleation plays the major role and new fibrils gain properties predicted by the environment rather than the structure of the seeds. Our findings could explain conformational switching between amyloid strains observed in a wide variety of in vivo and in vitro experiments.

No MeSH data available.


Related in: MedlinePlus

Denaturation profiles of rPrP-A2M and rPrP-A4M fibrils in GuSCN reveal different conformational stabilities.Standard errors calculated from 6 measurements using Student’s t-distribution at P = 0.05.
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fig-1: Denaturation profiles of rPrP-A2M and rPrP-A4M fibrils in GuSCN reveal different conformational stabilities.Standard errors calculated from 6 measurements using Student’s t-distribution at P = 0.05.

Mentions: Conformational stability of PrPSc as defined by resistance to chemical denaturation has been one of the key parameters used to define differences between strains (Colby et al., 2009). Different strains of recombinant mammalian prion protein amyloid-like fibrils made in 2 and 4 M guanidine hydrochloride (rPrP-A2M and rPrP-A4M, respectively) were thoroughly characterized by Surewicz group (Cobb et al., 2014). We used recombinant N-terminally truncated mouse prion protein (rMoPrP(89-230)) to create rPrP-A2M and rPrP-A4M strains of amyloid-like fibrils. Similar to recent data on recombinant human PrP (Cobb et al., 2014), rMoPrP fibrils formed in 2 and 4 M guanidine hydrochloride (GuHCl) have different conformational stability (Fig. 1). Due to the fact that rPrP-A4M fibrils could not be fully denatured using even 7.5 M GuHCl (Cobb et al., 2014), a denaturation assay using a more strongly chaotropic salt, guanidine thiocynate (GuSCN) was performed. Midpoint of denaturation of rPrP-A2M is at ∼1.8 M GuSCN and rPrP-A4M is at ∼3 M GuSCN, respectively. This difference served as a simple, unbiased marker of different strains in further experiments.


Polymorphism of amyloid-like fibrils can be defined by the concentration of seeds.

Sneideris T, Milto K, Smirnovas V - PeerJ (2015)

Denaturation profiles of rPrP-A2M and rPrP-A4M fibrils in GuSCN reveal different conformational stabilities.Standard errors calculated from 6 measurements using Student’s t-distribution at P = 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4563235&req=5

fig-1: Denaturation profiles of rPrP-A2M and rPrP-A4M fibrils in GuSCN reveal different conformational stabilities.Standard errors calculated from 6 measurements using Student’s t-distribution at P = 0.05.
Mentions: Conformational stability of PrPSc as defined by resistance to chemical denaturation has been one of the key parameters used to define differences between strains (Colby et al., 2009). Different strains of recombinant mammalian prion protein amyloid-like fibrils made in 2 and 4 M guanidine hydrochloride (rPrP-A2M and rPrP-A4M, respectively) were thoroughly characterized by Surewicz group (Cobb et al., 2014). We used recombinant N-terminally truncated mouse prion protein (rMoPrP(89-230)) to create rPrP-A2M and rPrP-A4M strains of amyloid-like fibrils. Similar to recent data on recombinant human PrP (Cobb et al., 2014), rMoPrP fibrils formed in 2 and 4 M guanidine hydrochloride (GuHCl) have different conformational stability (Fig. 1). Due to the fact that rPrP-A4M fibrils could not be fully denatured using even 7.5 M GuHCl (Cobb et al., 2014), a denaturation assay using a more strongly chaotropic salt, guanidine thiocynate (GuSCN) was performed. Midpoint of denaturation of rPrP-A2M is at ∼1.8 M GuSCN and rPrP-A4M is at ∼3 M GuSCN, respectively. This difference served as a simple, unbiased marker of different strains in further experiments.

Bottom Line: The strains are enciphered by different misfolded conformations.Strain-like phenomena have also been reported in a number of other amyloid-forming proteins.Our findings could explain conformational switching between amyloid strains observed in a wide variety of in vivo and in vitro experiments.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biothermodynamics and Drug Design, Vilnius University, Institute of Biotechnology , Vilnius , Lithuania.

ABSTRACT
Prions are infectious proteins where the same protein may express distinct strains. The strains are enciphered by different misfolded conformations. Strain-like phenomena have also been reported in a number of other amyloid-forming proteins. One of the features of amyloid strains is the ability to self-propagate, maintaining a constant set of physical properties despite being propagated under conditions different from those that allowed initial formation of the strain. Here we report a cross-seeding experiment using strains formed under different conditions. Using high concentrations of seeds results in rapid elongation and new fibrils preserve the properties of the seeding fibrils. At low seed concentrations, secondary nucleation plays the major role and new fibrils gain properties predicted by the environment rather than the structure of the seeds. Our findings could explain conformational switching between amyloid strains observed in a wide variety of in vivo and in vitro experiments.

No MeSH data available.


Related in: MedlinePlus