A solution-state NMR method is proposed to investigate the dynamics of proteins that undergo reversible association with nanoparticles (NPs). We applied the recently developed dark-state exchange saturation transfer experiment to obtain residue-level dynamic information on a NP-adsorbed protein in the form of transverse spin relaxation rates, R2bound. Based on dynamic light scattering, fluorescence, circular dichroism, and NMR spectroscopy data, we show that the test protein, human liver fatty acid binding protein, interacts reversibly and peripherally with liposomal NPs without experiencing significant structural changes. The significant but modest saturation transfer from the bound state observed at 14.1 and 23.5 T static magnetic fields, and the small determined R2bound values were consistent with a largely unrestricted global motion at the lipid surface. Amino acid residues displaying faster spin relaxation mapped to a region that could represent the epitope of interaction with an extended phospholipid chain constituting the protein anchor. These results prove that atomic-resolution protein dynamics is accessible even after association with NPs, supporting the use of saturation transfer methods as powerful tools in bionanoscience.

Dynamics of a Globular Protein Adsorbed to Liposomal Nanoparticles

CECCON, Alberto;D'ONOFRIO, Mariapina;ASSFALG, Michael
2014

Abstract

A solution-state NMR method is proposed to investigate the dynamics of proteins that undergo reversible association with nanoparticles (NPs). We applied the recently developed dark-state exchange saturation transfer experiment to obtain residue-level dynamic information on a NP-adsorbed protein in the form of transverse spin relaxation rates, R2bound. Based on dynamic light scattering, fluorescence, circular dichroism, and NMR spectroscopy data, we show that the test protein, human liver fatty acid binding protein, interacts reversibly and peripherally with liposomal NPs without experiencing significant structural changes. The significant but modest saturation transfer from the bound state observed at 14.1 and 23.5 T static magnetic fields, and the small determined R2bound values were consistent with a largely unrestricted global motion at the lipid surface. Amino acid residues displaying faster spin relaxation mapped to a region that could represent the epitope of interaction with an extended phospholipid chain constituting the protein anchor. These results prove that atomic-resolution protein dynamics is accessible even after association with NPs, supporting the use of saturation transfer methods as powerful tools in bionanoscience.
Protein dynamics; protein/nanoparticle interactions; NMR spectroscopy; dark-state exchange saturation transfer
File in questo prodotto:
File Dimensione Formato  
2014_JACS_Ceccon.pdf

solo utenti autorizzati

Descrizione: Articolo principale
Tipologia: Versione dell'editore
Licenza: Accesso ristretto
Dimensione 1.19 MB
Formato Adobe PDF
1.19 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11562/815164
Citazioni
  • ???jsp.display-item.citation.pmc??? 6
  • Scopus 23
  • ???jsp.display-item.citation.isi??? 25
social impact