Self-Organization Pathways and Spatial Heterogeneity in Insulin Amyloid Fibril Formation

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Abstract

At high temperature and low pH, the protein hormone insulin is highly prone to form amyloid fibrils, and for this reason it is widely used as a model system to study fibril formation mechanisms. In this work, we focused on insulin aggregation mechanisms occurring in HCl solutions (pH 1.6) at 60 °C. By means of in situ Thioflavin T (ThT) staining, the kinetics profiles were characterized as a function of the protein concentration, and two concurrent aggregation pathways were pointed out, being concentration dependent. In correspondence to these pathways, different morphologies of self-assembled protein molecules were detected by atomic force microscopy images also evidencing the presence of secondary nucleation processes as a peculiar mechanism for insulin fibrillation. Moreover, combining ThT fluorescence and light scattering, the early stages of the process were analyzed in the low concentration regime, pointing out a pronounced spatial heterogeneity in the formation of the first stable fibrils in solution and the onset of the secondary nucleation pathways.
Original languageEnglish
Pages (from-to)10830-10837
Number of pages8
JournalJOURNAL OF PHYSICAL CHEMISTRY. B, CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES & BIOPHYSICAL
Volume113
Publication statusPublished - 2009

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Amyloid
Insulin
Nucleation
Agglomeration
Proteins
Light scattering
Atomic force microscopy
Fluorescence
Hormones
Molecules
Kinetics
Temperature
thioflavin T

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Materials Chemistry
  • Surfaces, Coatings and Films

Cite this

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title = "Self-Organization Pathways and Spatial Heterogeneity in Insulin Amyloid Fibril Formation",
abstract = "At high temperature and low pH, the protein hormone insulin is highly prone to form amyloid fibrils, and for this reason it is widely used as a model system to study fibril formation mechanisms. In this work, we focused on insulin aggregation mechanisms occurring in HCl solutions (pH 1.6) at 60 °C. By means of in situ Thioflavin T (ThT) staining, the kinetics profiles were characterized as a function of the protein concentration, and two concurrent aggregation pathways were pointed out, being concentration dependent. In correspondence to these pathways, different morphologies of self-assembled protein molecules were detected by atomic force microscopy images also evidencing the presence of secondary nucleation processes as a peculiar mechanism for insulin fibrillation. Moreover, combining ThT fluorescence and light scattering, the early stages of the process were analyzed in the low concentration regime, pointing out a pronounced spatial heterogeneity in the formation of the first stable fibrils in solution and the onset of the secondary nucleation pathways.",
author = "Maurizio Leone and Pignataro, {Bruno Giuseppe} and Fabio Librizzi and Sebastiano Cataldo and Vito Foder{\`a}",
year = "2009",
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publisher = "American Chemical Society",

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T1 - Self-Organization Pathways and Spatial Heterogeneity in Insulin Amyloid Fibril Formation

AU - Leone, Maurizio

AU - Pignataro, Bruno Giuseppe

AU - Librizzi, Fabio

AU - Cataldo, Sebastiano

AU - Foderà, Vito

PY - 2009

Y1 - 2009

N2 - At high temperature and low pH, the protein hormone insulin is highly prone to form amyloid fibrils, and for this reason it is widely used as a model system to study fibril formation mechanisms. In this work, we focused on insulin aggregation mechanisms occurring in HCl solutions (pH 1.6) at 60 °C. By means of in situ Thioflavin T (ThT) staining, the kinetics profiles were characterized as a function of the protein concentration, and two concurrent aggregation pathways were pointed out, being concentration dependent. In correspondence to these pathways, different morphologies of self-assembled protein molecules were detected by atomic force microscopy images also evidencing the presence of secondary nucleation processes as a peculiar mechanism for insulin fibrillation. Moreover, combining ThT fluorescence and light scattering, the early stages of the process were analyzed in the low concentration regime, pointing out a pronounced spatial heterogeneity in the formation of the first stable fibrils in solution and the onset of the secondary nucleation pathways.

AB - At high temperature and low pH, the protein hormone insulin is highly prone to form amyloid fibrils, and for this reason it is widely used as a model system to study fibril formation mechanisms. In this work, we focused on insulin aggregation mechanisms occurring in HCl solutions (pH 1.6) at 60 °C. By means of in situ Thioflavin T (ThT) staining, the kinetics profiles were characterized as a function of the protein concentration, and two concurrent aggregation pathways were pointed out, being concentration dependent. In correspondence to these pathways, different morphologies of self-assembled protein molecules were detected by atomic force microscopy images also evidencing the presence of secondary nucleation processes as a peculiar mechanism for insulin fibrillation. Moreover, combining ThT fluorescence and light scattering, the early stages of the process were analyzed in the low concentration regime, pointing out a pronounced spatial heterogeneity in the formation of the first stable fibrils in solution and the onset of the secondary nucleation pathways.

UR - http://hdl.handle.net/10447/36316

M3 - Article

VL - 113

SP - 10830

EP - 10837

JO - Journal of Physical Chemistry B

JF - Journal of Physical Chemistry B

SN - 1520-6106

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