Characterizing Individual Protein Aggregates by Infrared Nanospectroscopy and Atomic Force Microscopy

Area of Science:

• Biochemistry
• Neuroscience
• Materials Science

Background:

• Protein misfolding and aggregation cause neurodegenerative diseases like Alzheimer's and Parkinson's.
• Amyloid oligomers, low molecular weight aggregates, are potent neurotoxins implicated in dementia.
• Heterogeneous and transient nature of protein aggregates challenges conventional study methods.

Purpose of the Study:

• To characterize morphological, structural, and chemical properties of protein aggregates.
• To demonstrate the utility of Atomic Force Microscopy-Infrared (AFM-IR) spectroscopy for aggregate analysis.
• To provide insights into protein aggregation mechanisms and therapeutic development.

Main Methods:

• Utilized Atomic Force Microscopy (AFM) for high-resolution imaging of protein aggregates.
• Employed AFM-Infrared (AFM-IR) spectroscopy to combine AFM's resolution with IR spectroscopy's chemical analysis.
• Investigated individual protein aggregates at sub-nanometer resolution.

Main Results:

• AFM-IR successfully characterized the morphology and structure of individual protein aggregates.
• The method provided insights into the aggregation mechanisms of neurotoxic species.
• Demonstrated the potential for studying interactions between protein assemblies and therapeutic compounds.

Conclusions:

• AFM-IR is a powerful technique for analyzing heterogeneous protein aggregates.
• This approach offers fundamental information for developing diagnostics and therapeutics for neurodegenerative disorders.
• Enables detailed investigation of protein-small molecule and protein-antibody interactions relevant to disease treatment.