Since its beginnings in studying the mass of isotopes in the early 1900s, Mass Spectrometry (MS) has evolved such that molecules containing hundreds of thousands of atoms can now be accurately and sensitively measured. These twin benefits have led to MS becoming a vital tool for biology in the post-genomic era, providing a means of identifying proteins, quantifying their abundances, and assessing any modified forms. However MS is not limited to molecules held together by covalent chemical bonds and can be used to examine fragile protein assemblies in the gas phase.

MS within Instruct therefore provides a rapid and sensitive means for assessing the quaternary organisation of proteins. It is widely applicable, including to assemblies as large as viruses, containing intrinsically disordered regions, associated with membranes, or populating a range of oligomeric states. The state-of-the-art enables the determination of inter-subunit connectivity, protein shape and topology, and equilibrium dynamics. Combining this ability to inform on the quaternary structure level with analysis of the individual protein chains renders MS a vital bridge between proteomics and structural biology.