title: Dynamics of a globular protein adsorbed to liposomal nanoparticles.
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.
authors.affiliation: Department of Biotechnology, University of Verona , Strada Le Grazie 15, 37134 Verona, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Ceccon
authors.forename: Moreno
authors.initials: M
authors.lastname: Lelli
authors.forename: Mariapina
authors.initials: M
authors.lastname: D'Onofrio
authors.forename: Henriette
authors.initials: H
authors.lastname: Molinari
authors.forename: Michael
authors.initials: M
authors.lastname: Assfalg
mesh_terms: D000327:Adsorption; D002784:Cholesterol / Q000737:chemistry / Q000378:metabolism; D050556:Fatty Acid-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D053758:Nanoparticles / Q000737:chemistry / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D010743:Phospholipids / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding
chemical_list: C493319:FABP1 protein, human; D050556:Fatty Acid-Binding Proteins; D008081:Liposomes; D010743:Phospholipids; D002784:Cholesterol