Sequestration of a β‐Hairpin for Control of α‐Synuclein Aggregation

Abstract

The misfolding and aggregation of the protein α-synuclein (α-syn), which results in the formation of amyloid fibrils, is involved in the pathogenesis of Parkinson's disease and other synucleinopathies. The emergence of amyloid toxicity is associated with the formation of partially folded aggregation intermediates. Here, we engineered a class of binding proteins termed β-wrapins (β-wrap proteins) with affinity for α-synuclein (α-syn). The NMR structure of an α-syn:β-wrapin complex reveals a β-hairpin of α-syn comprising the sequence region α-syn(37-54). The β-wrapin inhibits α-syn aggregation and toxicity at substoichiometric concentrations, demonstrating that it interferes with the nucleation of aggregation.

X-ray Crystallographic Structure of a Compact Dodecamer from a Peptide Derived from Aβ16–36

“…1 The twisted shape, exposed hydrogen-bonding edges, and hydrophobic surfaces of β-hairpins impart a unique propensity to self-assemble. Characterization of the assemblies that form at high-resolution has been challenging, because the resulting amyloid oligomers are heterogeneous and polymorphic.…”

Contact between the β1 and β2 Segments of α‐Synuclein that Inhibits Amyloid Formation

“…[10] In complex with AS69, a-syn locally adopts a b-hairpin conformation with b-strands comprising residues 37-43 and 48-54, reminiscent of the b1 and b2s trands of fibrillar a-syn. [10] Thet ertiary contacts between the b-strands of the AS69-bound b-hairpin agree well with the b1-b2contact map of free monomeric a-syn.…”

Alternative Conformations of the Tau Repeat Domain in Complex with an Engineered Binding Protein

“…The determination of the high-resolution NMR structures of the K18 ⌬K AA⅐TP4 complexes was precluded by the absence of resonance signals of the bound state due to intermediate exchange. However, the presence of two sequence stretches with high ␤-structure propensity in each of the binding regions suggests the presence of ␤-sheet structure in bound K18, possibly similar to the ␤-hairpin motifs of A␤ bound to the ␤-wrapin scaffold protein ZA␤ 3 (28) and of ␣-synuclein bound to the ␤-wrapin AS69 (26). For the binding site Tau(268 -317), the regions around PHF6* and PHF6 could contribute ␤-strands to a ␤-sheet, whereas the regions around PHF6 and PHF6** could do so for the binding site Tau(300 -349) (Fig.…”

“…TP4 belongs to the class of ␤-wrapins (␤-wrap proteins), which are selected from phage display libraries based on the ZA␤ 3 scaffold (26). ZA␤ 3 is a disulfide-linked homodimeric protein derived from the Z domain of protein A (27,28).…”

“…ZA␤ 3 binds the amyloid-␤ peptide (A␤) with nanomolar affinity, stabilizing a ␤-hairpin conformation of A␤ and inhibiting A␤ aggregation (28 dence obtained by protein engineering, NMR spectroscopy, molecular dynamics simulations, and FTIR spectroscopy suggests that the ␤-hairpin conformation observed in complex with the binding protein is also transiently populated in free A␤ monomers and constitutes a component of A␤ oligomers and protofibrils (29 -32). The ␤-wrapin AS69 selected to bind the protein ␣-synuclein involved in Parkinson disease likewise stabilizes a ␤-hairpin of the target protein and inhibits ␣-synuclein aggregation at substoichiometric concentration (26).…”