Morphological and Biophysical Study of S100A9 Protein Fibrils by Atomic Force Microscopy Imaging and Nanomechanical Analysis

Atomic force microscopy (AFM) imaging enables the visualization of protein molecules with high resolution, providing insights into their shape, size, and surface topography. Here, we use AFM to study the aggregation process of protein S100A9 in physiological conditions, in the presence of calcium at...

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Main Authors: Ana P. Carapeto, Carlos Marcuello, Patrícia F. N. Faísca, Mário S. Rodrigues
Format: Article
Language:English
Published: MDPI AG 2024-08-01
Series:Biomolecules
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Online Access:https://www.mdpi.com/2218-273X/14/9/1091
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author Ana P. Carapeto
Carlos Marcuello
Patrícia F. N. Faísca
Mário S. Rodrigues
author_facet Ana P. Carapeto
Carlos Marcuello
Patrícia F. N. Faísca
Mário S. Rodrigues
author_sort Ana P. Carapeto
collection DOAJ
description Atomic force microscopy (AFM) imaging enables the visualization of protein molecules with high resolution, providing insights into their shape, size, and surface topography. Here, we use AFM to study the aggregation process of protein S100A9 in physiological conditions, in the presence of calcium at a molar ratio 4Ca<sup>2+</sup>:S100A9. We find that S100A9 readily assembles into a worm-like fibril, with a period dimension along the fibril axis of 11.5 nm. The fibril’s chain length extends up to 136 periods after an incubation time of 144 h. At room temperature, the fibril’s bending stiffness was found to be <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2.95</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>28</mn></mrow></msup></mrow></semantics></math></inline-formula> Nm<sup>2</sup>, indicating that the fibrils are relatively flexible. Additionally, the values obtained for the Young’s modulus (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>E</mi><mi>x</mi></msub><mo>=</mo><mn>6.96</mn><mo>×</mo><msup><mn>10</mn><mn>5</mn></msup></mrow></semantics></math></inline-formula> Pa and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>E</mi><mi>y</mi></msub><mo>=</mo><mn>3.37</mn><mo>×</mo><msup><mn>10</mn><mn>5</mn></msup></mrow></semantics></math></inline-formula> Pa) are four orders of magnitude lower than those typically reported for canonical amyloid fibrils. Our findings suggest that, under the investigated conditions, a distinct aggregation mechanism may be in place in the presence of calcium. Therefore, the findings reported here could have implications for the field of biomedicine, particularly with regard to Alzheimer’s disease.
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spelling doaj-art-e2d72e8ed5d84489aa3e7e9fb5324ae52025-08-20T01:56:00ZengMDPI AGBiomolecules2218-273X2024-08-01149109110.3390/biom14091091Morphological and Biophysical Study of S100A9 Protein Fibrils by Atomic Force Microscopy Imaging and Nanomechanical AnalysisAna P. Carapeto0Carlos Marcuello1Patrícia F. N. Faísca2Mário S. Rodrigues3BioISI—Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, PortugalBioISI—Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, PortugalBioISI—Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, PortugalBioISI—Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, PortugalAtomic force microscopy (AFM) imaging enables the visualization of protein molecules with high resolution, providing insights into their shape, size, and surface topography. Here, we use AFM to study the aggregation process of protein S100A9 in physiological conditions, in the presence of calcium at a molar ratio 4Ca<sup>2+</sup>:S100A9. We find that S100A9 readily assembles into a worm-like fibril, with a period dimension along the fibril axis of 11.5 nm. The fibril’s chain length extends up to 136 periods after an incubation time of 144 h. At room temperature, the fibril’s bending stiffness was found to be <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2.95</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>28</mn></mrow></msup></mrow></semantics></math></inline-formula> Nm<sup>2</sup>, indicating that the fibrils are relatively flexible. Additionally, the values obtained for the Young’s modulus (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>E</mi><mi>x</mi></msub><mo>=</mo><mn>6.96</mn><mo>×</mo><msup><mn>10</mn><mn>5</mn></msup></mrow></semantics></math></inline-formula> Pa and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>E</mi><mi>y</mi></msub><mo>=</mo><mn>3.37</mn><mo>×</mo><msup><mn>10</mn><mn>5</mn></msup></mrow></semantics></math></inline-formula> Pa) are four orders of magnitude lower than those typically reported for canonical amyloid fibrils. Our findings suggest that, under the investigated conditions, a distinct aggregation mechanism may be in place in the presence of calcium. Therefore, the findings reported here could have implications for the field of biomedicine, particularly with regard to Alzheimer’s disease.https://www.mdpi.com/2218-273X/14/9/1091atomic force microscopyS100A9biomolecular processesoligomerizationprotein fibrilsmechanical properties
spellingShingle Ana P. Carapeto
Carlos Marcuello
Patrícia F. N. Faísca
Mário S. Rodrigues
Morphological and Biophysical Study of S100A9 Protein Fibrils by Atomic Force Microscopy Imaging and Nanomechanical Analysis
Biomolecules
atomic force microscopy
S100A9
biomolecular processes
oligomerization
protein fibrils
mechanical properties
title Morphological and Biophysical Study of S100A9 Protein Fibrils by Atomic Force Microscopy Imaging and Nanomechanical Analysis
title_full Morphological and Biophysical Study of S100A9 Protein Fibrils by Atomic Force Microscopy Imaging and Nanomechanical Analysis
title_fullStr Morphological and Biophysical Study of S100A9 Protein Fibrils by Atomic Force Microscopy Imaging and Nanomechanical Analysis
title_full_unstemmed Morphological and Biophysical Study of S100A9 Protein Fibrils by Atomic Force Microscopy Imaging and Nanomechanical Analysis
title_short Morphological and Biophysical Study of S100A9 Protein Fibrils by Atomic Force Microscopy Imaging and Nanomechanical Analysis
title_sort morphological and biophysical study of s100a9 protein fibrils by atomic force microscopy imaging and nanomechanical analysis
topic atomic force microscopy
S100A9
biomolecular processes
oligomerization
protein fibrils
mechanical properties
url https://www.mdpi.com/2218-273X/14/9/1091
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AT patriciafnfaisca morphologicalandbiophysicalstudyofs100a9proteinfibrilsbyatomicforcemicroscopyimagingandnanomechanicalanalysis
AT mariosrodrigues morphologicalandbiophysicalstudyofs100a9proteinfibrilsbyatomicforcemicroscopyimagingandnanomechanicalanalysis