Characterization of <i>In Vivo</i> Protein Complexes <i>via</i> Chemical Cross-Linking and Mass Spectrometry.
Abstact
Cells perform various functions by proteins <i>via</i> protein complexes. Characterization of protein complexes is critical to understanding their biological and clinical significance and has been one of the major efforts of functional proteomics. To date, most protein complexes are characterized by the <i>in vitro</i> system from protein extracts after the cells or tissues are lysed, and it has been challenging to determine which of these protein complexes are formed in intact cells. Herein, we report an approach to preserve protein complexes using <i>in vivo</i> cross-linking, followed by size exclusion chromatography and data-independent acquisition mass spectrometry. This approach enables the characterization of <i>in vivo</i> protein complexes from cells or tissues, which allows the determination of protein complexes in clinical research. More importantly, the described approach can identify protein complexes that are not detected by the <i>in vitro</i> system, which provide unique protein function information.