title: Paramagnetic Nanoparticles Leave Their Mark on Nuclear Spins of Transiently Adsorbed Proteins.
abstract: The successful application of nanomaterials in biosciences necessitates an in-depth understanding of how they interface with biomolecules. Transient associations of proteins with nanoparticles (NPs) are accessible by solution NMR spectroscopy, albeit with some limitations. The incorporation of paramagnetic centers into NPs offers new opportunities to explore bio-nano interfaces. We propose NMR paramagnetic relaxation enhancement as a new tool to detect NP-binding surfaces on proteins with increased sensitivity, also extending the applicability of NMR investigations to heterogeneous biomolecular mixtures. The adsorption of ubiquitin on gadolinium-doped fluoride-based NPs produced residue-specific NMR line-broadening effects mapping to a contiguous area on the surface of the protein. Importantly, an identical paramagnetic fingerprint was observed in the presence of a competing protein-protein association equilibrium, exemplifying possible interactions taking place in crowded biological media. The interaction was further characterized using isothermal titration calorimetry and upconversion emission measurements. The data indicate that the used fluoride-based NPs are not biologically inert but rather are capable of biomolecular recognition.
authors.affiliation: Biomolecular NMR Laboratory, Department of Biotechnology, University of Verona , 37134 Verona, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Zanzoni
authors.affiliation: Nanomaterials Research Group, Department of Biotechnology, University of Verona and INSTM , 37134 Verona, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Pedroni
authors.affiliation: Biomolecular NMR Laboratory, Department of Biotechnology, University of Verona , 37134 Verona, Italy.
authors.forename: Mariapina
authors.initials: M
authors.lastname: D'Onofrio
authors.affiliation: Nanomaterials Research Group, Department of Biotechnology, University of Verona and INSTM , 37134 Verona, Italy.
authors.forename: Adolfo
authors.initials: A
authors.lastname: Speghini
authors.affiliation: Biomolecular NMR Laboratory, Department of Biotechnology, University of Verona , 37134 Verona, Italy.
authors.forename: Michael
authors.initials: M
authors.lastname: Assfalg
mesh_terms: D000327:Adsorption; D009682:Magnetic Resonance Spectroscopy; D008280:Magnetics; D053758:Nanoparticles; D011506:Proteins / Q000737:chemistry*
chemical_list: D011506:Proteins