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  • Single molecule secondary structure determination of proteins through infrared absorption nanospectroscopy.

Single molecule secondary structure determination of proteins through infrared absorption nanospectroscopy.

Nature communications (2020-06-12)
Francesco Simone Ruggeri, Benedetta Mannini, Roman Schmid, Michele Vendruscolo, Tuomas P J Knowles
ABSTRACT

The chemical and structural properties of biomolecules determine their interactions, and thus their functions, in a wide variety of biochemical processes. Innovative imaging methods have been developed to characterise biomolecular structures down to the angstrom level. However, acquiring vibrational absorption spectra at the single molecule level, a benchmark for bulk sample characterization, has remained elusive. Here, we introduce off-resonance, low power and short pulse infrared nanospectroscopy (ORS-nanoIR) to allow the acquisition of infrared absorption spectra and chemical maps at the single molecule level, at high throughput on a second timescale and with a high signal-to-noise ratio (~10-20). This high sensitivity enables the accurate determination of the secondary structure of single protein molecules with over a million-fold lower mass than conventional bulk vibrational spectroscopy. These results pave the way to probe directly the chemical and structural properties of individual biomolecules, as well as their interactions, in a broad range of chemical and biological systems.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Apoferritin from equine spleen
Sigma-Aldrich
Thyroglobulin from bovine thyroid, (For Gel Filtration Chromatography)