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Protein conformational changes probed by infrared nano-spectroscopy.

Giliberti V.
  Lunedì 12/09   14:00 - 19:00   Aula D - Marianna Ciccone   II - Fisica della materia   Presentazione
Atomic force microscopy-based infrared (IR) methods enable IR nano-spectroscopy and nano-imaging with a resolution far below the conventional optical diffraction limit. These approaches have emerged as a frontier for the study of complex heterogeneous materials and nanometer-sized ones, finding applications in a variety of fields including the study of 2D materials, plasmonic structures and biomolecules. Here we apply AFM-assisted IR nano-spectroscopy based on the photothermal expansion effect (AFM-IR) to the study of protein conformational changes, $i.e.$, the modifications of the native 3D protein structure that are strictly related to the role of proteins in living cells. By exploiting the field enhancement in the plasmonic nanogap that forms between a gold-coated AFM tip and an ultraflat gold surface, we were able to probe the slight functional conformational changes with an unprecedented sensitivity of less than 100 molecules. After a brief introduction on the physics underlying the AFM-IR technique, I will present our recent results obtained on i) cell membrane flakes embedding optogenetic proteins, and ii) toxic aggregates of a protein relevant for neurological diseases.