Evidence for a central role of PrP helix 2 in the nucleation of amyloid fibrils

Abstract

Amyloid fibrils are filamentous protein aggregates associated with the pathogenesis of a wide variety of human diseases. The formation of such aggregates typically follows nucleation-dependent kinetics, wherein the assembly and structural conversion of amyloidogenic proteins into oligomeric aggregates (nuclei) is the rate-limiting step of the overall reaction. In this study, we sought to gain structural insights into the oligomeric nuclei of the human prion protein (PrP) by preparing a series of deletion mutants lacking 14-44 of the C-terminal 107 residues of PrP and examined the kinetics and thermodynamics of these mutants in amyloid formation. An analysis of the experimental data using the concepts of the Φ-value analysis indicated that the helix 2 region (residues 168-196) acquires an amyloid-like β-sheet during nucleation, whereas the other regions preserves a relatively disordered structure in the nuclei. This finding suggests that the helix 2 region serves as the nucleation site for the assembly of amyloid fibrils.-Honda, R., Kuwata, K. Evidence for a central role of PrP helix 2 in the nucleation of amyloid fibrils.

Amyloid‐β Peptide Induces Prion Protein Amyloid Formation: Evidence for Its Widespread Amyloidogenic Effect

“…[14] Given that Helix 2i snot required for the binding of PrP to Ab (Group II of Table 1), aH elix 2d eletion is expected to reduce the intrinsic amyloidogenic propensity without affecting the binding capacity with Ab.T herefore,apartial Helix 2 deletion was next included with the D23-123/D124-167 variant to produce triple deletion mutants (D23-123/D124-167/D168-181 and D23-123/D124-167/D182-196). [14] Given that Helix 2i snot required for the binding of PrP to Ab (Group II of Table 1), aH elix 2d eletion is expected to reduce the intrinsic amyloidogenic propensity without affecting the binding capacity with Ab.T herefore,apartial Helix 2 deletion was next included with the D23-123/D124-167 variant to produce triple deletion mutants (D23-123/D124-167/D168-181 and D23-123/D124-167/D182-196).…”

Interaction between Hemin and Prion Peptides: Binding, Oxidative Reactivity and Aggregation

“…The aggregation process and the formation of amyloid fibrils of prion protein is the key event associated with the onset of prion diseases. The portion between the residues 90–140 has been historically identified as the most important for the aggregation process (amyloidogenic region), even if recently the hypothesis that also the region from 170 to 220, including helix 2 and helix 3, has been raised [ 46 , 47 ].…”

Amyloid‐β Peptide Induces Prion Protein Amyloid Formation: Evidence for Its Widespread Amyloidogenic Effect

“…The author recently demonstrated that a partial deletion of residues 168–196 (Helix 2 region) reduced the amyloidogenic propensity of PrP . Given that Helix 2 is not required for the binding of PrP to Aβ (Group II of Table ), a Helix 2 deletion is expected to reduce the intrinsic amyloidogenic propensity without affecting the binding capacity with Aβ.…”

“…Thea uthor recently prepared as eries of PrP variants carrying different deletions of the C-terminal domain (Group II of Table 1a nd the Supporting Information, Figure S6) [14] and the complete deletion of the N-terminal domain (D23-123). These eight variants were next examined to investigate which regions of the C-terminal domain of PrP are required for the coaggregation reaction.…”