In biological systems, nanoparticles (NPs) elicit bioactivity upon interaction with proteins. As a result of post-translational modification, proteins occur in a variety of alternative covalent forms, including structural isomers, which present unique molecular surfaces. We aimed at a detailed description of the recognition of protein isomeric species by NP surfaces. The transient adsorption of isomeric ubiquitin (Ub) dimers by NPs was investigated by solution NMR spectroscopy. Lys63- and Lys48-linked Ub2 were adsorbed by large anionic NPs with different affinities, whereas the binding strength was similar in the cases of smaller particles. After the incorporation of paramagnetic tags into NPs, the observed site-resolved paramagnetic footprints provided a high-resolution map of the different protein surfaces binding to NPs. The approach described could be extended to further protein isoforms and more specialized NP systems to allow better control of the interactions between NPs and protein targets.

Specific Interaction Sites Determine Differential Adsorption of Protein Structural Isomers on Nanoparticle Surfaces

Bortot, Andrea;Zanzoni, Serena;D'Onofrio, Mariapina;Assfalg, Michael
2018-01-01

Abstract

In biological systems, nanoparticles (NPs) elicit bioactivity upon interaction with proteins. As a result of post-translational modification, proteins occur in a variety of alternative covalent forms, including structural isomers, which present unique molecular surfaces. We aimed at a detailed description of the recognition of protein isomeric species by NP surfaces. The transient adsorption of isomeric ubiquitin (Ub) dimers by NPs was investigated by solution NMR spectroscopy. Lys63- and Lys48-linked Ub2 were adsorbed by large anionic NPs with different affinities, whereas the binding strength was similar in the cases of smaller particles. After the incorporation of paramagnetic tags into NPs, the observed site-resolved paramagnetic footprints provided a high-resolution map of the different protein surfaces binding to NPs. The approach described could be extended to further protein isoforms and more specialized NP systems to allow better control of the interactions between NPs and protein targets.
2018
NMR spectroscopy; molecular recognition; nanoparticles; paramagnetic relaxation enhancement; protein-nanoparticle interactions; Adsorption; Isomerism; Molecular Structure; Nanoparticles; Nuclear Magnetic Resonance, Biomolecular; Protein Binding; Protein Processing, Post-Translational; Proteins; Ubiquitin
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11562/988281
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