Exploration of possible binding sites of nanoparticles on protein by crosslinking chemistry coupled with mass spectrometry

摘要

For the first time, the possible binding site of nanoparticles on protein was revealed by crosslinking chemistry coupled with mass spectrometry. The peptides locating very close to the polyacrylic acid (PAA)-coated Fe3O4 nanoparticles (NPs) during interaction with human serum albumin (HSA) were crosslinked to the surface of NPs. Following protease digestion, the attached peptides were cleaved off the particle surface, and identified by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS). The peptides were found to be part of the so-called drug binding site 2 of HSA; and the competitive binding to HSA between the corresponding drug, ibuprofen, and the NPs was observed. Our results demonstrated that crosslinking chemistry coupled with MS was a quick and simple method for locating the possible binding sites of NPs on protein. Information on NP-protein binding interface will benefit study of how the interactions are governed by the physicochemical properties of NPs, for guiding the design of functional bio-nano constructs. It can also help to predict the biological consequence of protein adsorption on NPs, for obtaining more knowledge on nanotoxicity.