Emerging native Orbitrap mass spectrometry for probing higher-order structures of proteins: Recent progress and applications

Abstract

Native mass spectrometry ( MS) is a powerful and complementary tool and has been widely used for the characterization of proteins and protein complexes. Over the past decades, several mass analyzers have been developed with extended mass range and increased mass resolution for the analysis of higher-order structures of native macromolecular assemblies. In particular, the Orbitrap mass analyzer has attracted considerable interest due to its superior desolvation and resolution capabilities. In this review, the recent progress of native Orbitrap-MS in the characterization of higher-order structures of proteins is summarized. A brief introduction to the evolution of Orbitrap mass analyzer and commonly used ionization techniques in Orbitrap mass spectrometers is presented, including electrospray ionization (ESI), nanoESI, and desorption ESI (DESI). Then, four activation techniques in tandem MS and their applications in native Orbitrap-MS are examined. The applications of native Orbitrap-MS are emphasized according to three main aspects: membrane proteins, protein assemblies, and proteoform profiling. Finally, future perspectives and challenges are explored regarding the instrumentation and research orientations of Orbitrap-MS. This review provides the scientific community with a comprehensive understanding of native Orbitrap-MS for the analysis of large macromolecular assemblies and encourages the promotion of Orbitrap-MS.