Global properties and propensity to dimerization of the amyloid-beta (12-28) peptide fragment through the modeling of its monomer and dimer diffusion coefficients and electrophoretic mobilities.
Neuronal activity loss may be due to toxicity caused mainly by amyloid-beta (1-40) and (1-42) peptides forming soluble oligomers. Here the amyloid-beta (12-28) peptide fragment (monomer) and its dimer are characterized at low pH through the modeling of their diffusion coefficients and effective electrophoretic mobilities. Translational diffusion coefficient experimental values of monomer and dimer analogs of this peptide fragment and monomer and dimer mixtures at thermodynamic equilibrium are used as reported in the literature for different monomer initial concentrations. The resulting electrokinetic and hydrodynamic global properties are employed to evaluate the amyloid-beta (12-28) peptide fragment propensity to dimerization through a thermodynamic theoretical framework. Therefore equilibrium constants are considered at pH 2.9 to elucidate one of the amyloidogenic mechanisms involving the central hydrophobic region LVFFA of the peptide spanning residues 17-21 associated with phenylalanine at positions 19 and 20 in the amino acid sequence of amyloid-beta peptides. An analysis demonstrating that peptide aggregation is a concentration-dependent process is provided, where both pair and intraparticle charge regulation phenomena become relevant. It is shown that the modeling of the effective electrophoretic mobility of the amyloid-beta (12-28) peptide fragment is crucial to understand the effect of hydrophobic region LVFFA in the amyloidogenic process.
Instituto de Desarrollo Tecnológico para la Industria Química (INTEC), Universidad Nacional del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Santa Fe, Argentina.
Julio A
JA
Deiber
Marta B
MB
Peirotti
Maria V
MV
Piaggio
D000595:Amino Acid Sequence; D016229:Amyloid beta-Peptides / Q000737:chemistry* / Q000378:metabolism*; D004058:Diffusion; D004586:Electrophoresis / Q000379:methods; D057446:Hydrodynamics; D008956:Models, Chemical; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism*; D055503:Protein Multimerization; D013816:Thermodynamics
D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; C092395:amyloid beta-protein (12-28)
Amyloid-beta fragment; Charge regulation phenomena; Dimerization equilibrium; Effective electrophoretic mobility; Translational diffusion coefficient