Delineating the Role of Helical Intermediates in Natively Unfolded Polypeptide Amyloid Assembly and Cytotoxicity

2015 ◽  
Vol 127 (48) ◽  
pp. 14591-14595 ◽  
Author(s):  
Carole Anne De Carufel ◽  
Noé Quittot ◽  
Phuong Trang Nguyen ◽  
Steve Bourgault
Keyword(s):  
Natively Unfolded ◽  
Amyloid Assembly

Delineating the Role of Helical Intermediates in Natively Unfolded Polypeptide Amyloid Assembly and Cytotoxicity

2015 ◽  
Vol 54 (48) ◽  
pp. 14383-14387 ◽  
Author(s):  
Carole Anne De Carufel ◽  
Noé Quittot ◽  
Phuong Trang Nguyen ◽  
Steve Bourgault
Keyword(s):  
Natively Unfolded ◽  
Amyloid Assembly

scholarly journals Probing the Role of PrP Repeats in Conformational Conversion and Amyloid Assembly of Chimeric Yeast Prions

2007 ◽  
Vol 282 (47) ◽  
pp. 34204-34212 ◽  
Author(s):  
Jijun Dong ◽  
Jesse D. Bloom ◽  
Vladimir Goncharov ◽  
Madhuri Chattopadhyay ◽  
Glenn L. Millhauser ◽  
...  
Keyword(s):  
Yeast Prions ◽  
Amyloid Assembly ◽  
Conformational Conversion

scholarly journals Understanding Amyloid Assembly of Natively Unfolded Polypeptide by Means of Conformationally Restricted Peptides

2016 ◽  
Vol 110 (3) ◽  
pp. 219a
Author(s):  
Noé Quittot ◽  
De Carufel ◽  
Carole Anne ◽  
Phuong Trang Nguyen ◽  
Steve Bourgault
Keyword(s):  
Conformationally Restricted ◽  
Natively Unfolded ◽  
Amyloid Assembly

scholarly journals Mapping the sequence specificity of heterotypic amyloid interactions enables the identification of aggregation modifiers

2021 ◽  
Author(s):  
Nikolaos N Louros ◽  
Meine Ramakers ◽  
Emiel Michiels ◽  
Katerina Konstantoulea ◽  
Chiara Morelli ◽  
...  
Keyword(s):  
Sequence Homology ◽  
Protein Sequences ◽  
Sequence Specificity ◽  
Structural Mechanism ◽  
Structural Rules ◽  
Amyloidogenic Proteins ◽  
Systematic Understanding ◽  
Fibril Morphology ◽  
Amyloid Assembly

Heterotypic amyloid interactions between related protein sequences have been observed in functional and disease amyloids. While sequence homology seems to favour heterotypic amyloid interactions, we have no systematic understanding of the structural rules determining such interactions nor whether they inhibit or facilitate amyloid assembly. Using structure-based thermodynamic calculations and extensive experimental validation, we performed a comprehensive exploration of the defining role of sequence promiscuity in amyloid interactions. Using this knowledge, we demonstrate, using tau as a model system, that predicted cross-interactions driven by sequence homology indeed can modify nucleation, fibril morphology, kinetic assembly and cellular spreading of aggregates. We also find that these heterotypic amyloid interactions can result in the mis-localisation of brain-expressed protein sequences with prevalent activities in neurodegenerative disorders. Our findings suggest a structural mechanism by which the proteomic background can modulate the aggregation propensity of amyloidogenic proteins and discuss how such sequence-specific proteostatic perturbations could contribute to the selective cellular susceptibility of amyloid disease progression.

scholarly journals The role of the IT-state in D76N β2-microglobulin amyloid assembly: A crucial intermediate or an innocuous bystander?

2020 ◽  
Vol 295 (35) ◽  
pp. 12474-12484 ◽  
Author(s):  
Hugh I. Smith ◽  
Nicolas Guthertz ◽  
Emma E. Cawood ◽  
Roberto Maya-Martinez ◽  
Alexander L. Breeze ◽  
...  
Keyword(s):  
Amino Acids ◽  
Single Amino Acid ◽  
Folding Intermediate ◽  
Exposed Site ◽  
Aggregation Propensity ◽  
Amyloid Disease ◽  
Aggregation Rate ◽  
Amyloid Assembly

The D76N variant of human β2-microglobulin (β2m) is the causative agent of a hereditary amyloid disease. Interestingly, D76N-associated amyloidosis has a distinctive pathology compared with aggregation of WT-β2m, which occurs in dialysis-related amyloidosis. A folding intermediate of WT-β2m, known as the IT-state, which contains a nonnative trans Pro-32, has been shown to be a key precursor of WT-β2m aggregation in vitro. However, how a single amino acid substitution enhances the rate of aggregation of D76N-β2m and gives rise to a different amyloid disease remained unclear. Using real-time refolding experiments monitored by CD and NMR, we show that the folding mechanisms of WT- and D76N-β2m are conserved in that both proteins fold slowly via an IT-state that has similar structural properties. Surprisingly, however, direct measurement of the equilibrium population of IT using NMR showed no evidence for an increased population of the IT-state for D76N-β2m, ruling out previous models suggesting that this could explain its enhanced aggregation propensity. Producing a kinetically trapped analog of IT by deleting the N-terminal six amino acids increases the aggregation rate of WT-β2m but slows aggregation of D76N-β2m, supporting the view that although the folding mechanisms of the two proteins are conserved, their aggregation mechanisms differ. The results exclude the IT-state as the origin of the rapid aggregation of D76N-β2m, suggesting that other nonnative states must cause its high aggregation rate. The results highlight how a single substitution at a solvent-exposed site can affect the mechanism of aggregation and the resulting disease.

scholarly journals Molecular insights into the surface-catalyzed secondary nucleation of amyloid-β40 (Aβ40) by the peptide fragment Aβ16–22

2019 ◽  
Vol 5 (6) ◽  
pp. eaav8216 ◽  
Author(s):  
Samuel J. Bunce ◽  
Yiming Wang ◽  
Katie L. Stewart ◽  
Alison E. Ashcroft ◽  
Sheena E. Radford ◽  
...  
Keyword(s):  
Random Coil ◽  
Peptide Fragments ◽  
Secondary Nucleation ◽  
Dynamic Interactions ◽  
Structural Mechanism ◽  
Dynamics Simulations ◽  
Transient Intermediates ◽  
Amyloid Assembly ◽  
Amyloid Diseases

Understanding the structural mechanism by which proteins and peptides aggregate is crucial, given the role of fibrillar aggregates in debilitating amyloid diseases and bioinspired materials. Yet, this is a major challenge as the assembly involves multiple heterogeneous and transient intermediates. Here, we analyze the co-aggregation of Aβ40 and Aβ16–22, two widely studied peptide fragments of Aβ42 implicated in Alzheimer’s disease. We demonstrate that Aβ16–22 increases the aggregation rate of Aβ40 through a surface-catalyzed secondary nucleation mechanism. Discontinuous molecular dynamics simulations allowed aggregation to be tracked from the initial random coil monomer to the catalysis of nucleation on the fibril surface. Together, the results provide insight into how dynamic interactions between Aβ40 monomers/oligomers on the surface of preformed Aβ16–22 fibrils nucleate Aβ40 amyloid assembly. This new understanding may facilitate development of surfaces designed to enhance or suppress secondary nucleation and hence to control the rates and products of fibril assembly.

scholarly journals Conformational Priming of RepA-WH1 for Functional Amyloid Conversion Detected by NMR Spectroscopy

2019 ◽  
Author(s):  
David Pantoja-Uceda ◽  
Javier Oroz ◽  
Cristina Fernández ◽  
Eva de Alba ◽  
Rafael Giraldo ◽  
...  
Keyword(s):  
Structural Changes ◽  
Conformational Dynamics ◽  
Functional Abilities ◽  
Exchange Kinetics ◽  
Folded Proteins ◽  
Partially Unfolded ◽  
Α Helix ◽  
Amyloid Assembly ◽  
Small Molecule Ligand

AbstractHow proteins with a stable globular fold acquire the amyloid state is still largely unknown. RepA is a versatile plasmidic DNA binding protein, functional either as a transcriptional repressor or as an initiator or inhibitor of DNA replication, the latter through the assembly of an amyloidogenic oligomer. Its N-terminal domain (WH1) is responsible for discrimination between these functional abilities by undergoing hitherto unknown structural changes. Furthermore, when expressed alone, RepA-WH1 behaves as a synthetic prion-like protein causing an amyloid proteinopathy in bacteria. RepA-WH1 is a stable dimer whose conformational dynamics had not been explored. Here we have studied it through NMR {1H}-15N relaxation and H/D exchange kinetics measurements. The N- and the C- terminal α-helices, which lock the WH1 fold in each subunit of the dimer, as well as an internal amyloidogenic loop, show reduced stability and are partially unfolded in solution. S4-indigo, a small molecule ligand known to interfere with the amyloid assembly of RepA-WH1, binds to and tethers the N-terminal α-helix and a β-hairpin that is involved in dimerization, thus providing evidence for a priming role of fraying ends and dimerization switches in the amyloidogenesis of folded proteins.

Sign in / Sign up

Export Citation Format

Share Document