Native Mass Spectrometry Based Method for Studying the Interactions between Superoxide Dismutase 1 and Stilbenoids

To inhibit the abnormal aggregation of Cu, Zn-superoxide dismutase (SOD1) is regarded as a potential therapeutic strategy of SOD1-linked amyotrophic lateral sclerosis (ALS). Herein the interactions between SOD1 and four stilbene-based polyphenols, namely, resveratrol, oxyresveratrol, polydatin, and 2,3,4′,5-tetrahydroxystilbene-2-O-β-d-glycoside (THSG), were investigated using electrospray ionization mass spectrometry (ESI-MS) combined with ion mobility (IM) spectrometry. The addition of tandem MS to the study of SOD1–ligand complexes provides further insight into their gas-phase stability. Monitoring the unfolding of SOD1–ligand complexes using IM-MS allows observation of subtle changes in the protein stability upon ligand binding. From the MS/MS and IM-MS measurements, polydatin and THSG were highlighted as the strongest bound compounds in the gas phase, and both of them appear to provide a stabilizing effect on the SOD1 dimer conformation. In addition, the data of fluorescence assays clearly show the ability of the ligands to inhibit apoSOD1 from aggregation, and polydatin was found to have the strongest inhibitory effect. Overall, the method described here can be an effective approach to investigate the interactions between SOD1 and other drug-like molecules.