Proteolysis Degree of Protein Corona Affect Ultrasound-Induced Sublethal Effects on Saccharomyces cerevisiae: Transcriptomics Analysis and Adaptive Regulation of Membrane Homeostasis

Investigation on topology-dependent adsorption and aggregation of protein on nanoparticle surface enabled by integrating time-limited proteolysis with cross-linking mass spectrometry

The biological identity of nanomaterials is predominantly dictated by their surface protein corona (PC), yet the topological characteristics of most PCs remain uncharacterized in situ. We employed time-limited proteolysis combined time-segmented cross-linking mass spectrometry at specific intervals (10 min, 1 h, 2 h, 4 h and 18 h) to, for the first time, elucidate the spatial distribution, topological architecture and molecular orientation of multiple proteins within the multi-layered PC on nano-Fe3O4 surfaces. Additional monolinks, intermolecular and intramolecular crosslinks which were previously inaccessible to the crosslinker were unveiled in a layer-by-layer manner. 197 sparse intermolecular crosslinks involving 368 distinct wheat proteins were identified. Notably, charge complementarity and hydrophobic residue pairings, rather than hydrophobic peptide motifs, primarily govern the protein-protein interactions. For the crosslinks bridging the proteolysable and proteolysis-resistant layers, 72 % presented one end in a random coil conformation. Furthermore, the molecular orientation of 16 proteins including Q8L803, P11534 and P93594, etc., in the proteolysis-resistant layer was determined. The observation of violated intramolecular crosslinks between two rigid structural domains (e.g., A0A3B5Y430) suggests that nanoparticle-protein and protein-protein interactions may induce conformational changes in the adsorbed proteins. These findings offer novel insights into the spontaneous formation mechanisms of PC.

pH-Dependent HEWL-AuNPs Interactions: Optical Study

Optical methods (spectroscopy, spectrofluorometry, dynamic light scattering, and refractometry) were used to study the change in the state of hen egg-white lysozyme (HEWL), protein molecules, and gold nanoparticles (AuNPs) in aqueous colloids with changes in pH, and the interaction of protein molecules with nanoparticles was also studied. It was shown that changing pH may be the easiest way to control the protein corona on gold nanoparticles. In a colloid of nanoparticles, both in the presence and absence of protein, aggregation-deaggregation, and in a protein colloid, monomerization-dimerization-aggregation are the main processes when pH is changed. A specific point at pH 7.5, where a transition of the colloidal system from one state to another is observed, has been found using all the optical methods mentioned. It has been shown that gold nanoparticles can stabilize HEWL protein molecules at alkaline pH while maintaining enzymatic activity, which can be used in practice. The data obtained in this manuscript allow for the state of HEWL colloids and gold nanoparticles to be monitored using one or two simple and accessible optical methods.