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Salt Anions Promote the Conversion of HypF-N into Amyloid-Like Oligomers and Modulate the Structure of the Oligomers and the Monomeric Precursor State
- Source :
- Digital.CSIC. Repositorio Institucional del CSIC, instname
- Publication Year :
- 2012
-
Abstract
- An understanding of the solution factors contributing to the rate of aggregation of a protein into amyloid oligomers, to the modulation of the conformational state populated prior to aggregation and to the structure/morphology of the resulting oligomers is one of the goals of present research in this field. We have studied the influence of six different salts on the conversion of the N-terminal domain of Escherichia coli HypF (HypF-N) into amyloid-like oligomers under conditions of acidic pH. Our results show that salts having different anions (NaCl, NaClO4, NaI, Na 2SO4) accelerate oligomerization with an efficacy that follows the electroselectivity series of the anions (SO4 2- ≥ ClO4 - > I- > Cl-). By contrast, salts with different cations (NaCl, LiCl, KCl) have similar effects. We also investigated the effect of salts on the structure of the final and initial states of HypF-N aggregation. The electroselectivity series does not apply to the effect of anions on the structure of the oligomers. By contrast, it applies to their effect on the content of secondary structure and on the exposure of hydrophobic clusters of the monomeric precursor state. The results therefore indicate that the binding of anions to the positively charged residues of HypF-N at low pH is the mechanism by which salts modulate the rate of oligomerization and the structure of the monomeric precursor state but not the structure of the resulting oligomers. Overall, the data contribute to rationalize the effect of salts on amyloid-like oligomer formation and to explain the role of charged biological macromolecules in protein aggregation processes.
- Subjects :
- Anions
Protein Denaturation
Protein Conformation
Inorganic chemistry
Protein aggregation
medicine.disease_cause
Microscopy, Atomic Force
Oligomer
chemistry.chemical_compound
Structural Biology
Polymer chemistry
medicine
Molecular Biology
Escherichia coli
Protein secondary structure
Amyloid like
Circular Dichroism
Escherichia coli Proteins
Spectrum Analysis
Hydrogen-Ion Concentration
Monomer
chemistry
Polymorphism (materials science)
Carboxyl and Carbamoyl Transferases
Salts
Protein Multimerization
Macromolecule
Protein Binding
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- Digital.CSIC. Repositorio Institucional del CSIC, instname
- Accession number :
- edsair.doi.dedup.....4454498dd24f8935c651dfae8c74c44a