An Integrated Mass Spectrometry Based Approach to Probe the Structure of the Full-Length Wild-Type Tetrameric p53 Tumor Suppressor.

We present an integrated approach for investigating the topology of proteins through native mass spectrometry (MS) and cross-linking/MS, which we applied to the full-length wild-type p53 tetramer. For the first time, the two techniques were combined in one workflow to obtain not only structural insight in the p53 tetramer, but also information on the cross-linking efficiency and the impact of cross-linker modification on the conformation of an intrinsically disordered protein (IDP). P53 cross-linking was monitored by native MS and as such, our strategy serves as a quality control for different cross-linking reagents. Our approach can be applied to the structural investigation of various protein systems, including IDPs and large protein assemblies, which are challenging to study by the conventional methods used for protein structure characterization.