TY - JOUR
T1 - Effect of ionic strength on the aggregation kinetics of the amidated amyloid beta peptide Aβ (1-40) in aqueous solutions
AU - Campos-Ramírez, Adriana
AU - Márquez, Maripaz
AU - Quintanar, Liliana
AU - Rojas-Ochoa, Luis F.
N1 - Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2017/9
Y1 - 2017/9
N2 - In this work we study the effect of solution ionic strength on the structural evolution of amidated amyloid beta peptide Aβ (1-40) oligomers at the early stages of fibril formation. By light scattering, we follow the time evolution of the structure and short-time dynamics of peptide structures at low ionic strengths. Our results allow identifying initial oligomer structures as the effective building blocks in the amyloid fibrils formation and indicate that the oligomers growth pathway, from compact structures to flexible chain-like structures, becomes faster as the solution ionic strength is increased. Furthermore, we find no evidence of structural branching what suggests that elongation of amyloid fibrils is dominated by linear association. To describe our results we adapt a phenomenological model based on population balance equations and linear polymer growth, where the parameters required are obtained from the experiments. Model calculations are in good agreement with experimentally-obtained estimates for the radius of gyration of Aβ (1-40) oligomers, thus further supporting our findings. Additionally, we introduce a model for the effective interaction among initial Aβ structures that captures the dependence of the effective association rates on solution ionic strength.
AB - In this work we study the effect of solution ionic strength on the structural evolution of amidated amyloid beta peptide Aβ (1-40) oligomers at the early stages of fibril formation. By light scattering, we follow the time evolution of the structure and short-time dynamics of peptide structures at low ionic strengths. Our results allow identifying initial oligomer structures as the effective building blocks in the amyloid fibrils formation and indicate that the oligomers growth pathway, from compact structures to flexible chain-like structures, becomes faster as the solution ionic strength is increased. Furthermore, we find no evidence of structural branching what suggests that elongation of amyloid fibrils is dominated by linear association. To describe our results we adapt a phenomenological model based on population balance equations and linear polymer growth, where the parameters required are obtained from the experiments. Model calculations are in good agreement with experimentally-obtained estimates for the radius of gyration of Aβ (1-40) oligomers, thus further supporting our findings. Additionally, we introduce a model for the effective interaction among initial Aβ structures that captures the dependence of the effective association rates on solution ionic strength.
KW - Amyloid beta peptide
KW - Ionic strength
KW - Light scattering
KW - Linear polymer growth
KW - Oligomer
UR - http://www.scopus.com/inward/record.url?scp=85020113720&partnerID=8YFLogxK
U2 - 10.1016/j.bpc.2017.05.004
DO - 10.1016/j.bpc.2017.05.004
M3 - Artículo
C2 - 28587777
AN - SCOPUS:85020113720
SN - 0301-4622
VL - 228
SP - 98
EP - 107
JO - Biophysical Chemistry
JF - Biophysical Chemistry
ER -