How far can we go with structural mass spectrometry of protein complexes?

Abstract

Physical interactions between proteins and the formation of stable complexes form the basis of most biological functions. Therefore, a critical step toward understanding the integrated workings of the cell is to determine the structure of protein complexes, and reveal how their structural organization dictates function. Studying the three-dimensional organization of protein assemblies, however, represents a major challenge for structural biologists, due to the large size of the complexes, their heterogeneous composition, their flexibility, and their asymmetric structure. In the last decade, mass spectrometry has proven to be a valuable tool for analyzing such noncovalent complexes. Here, I illustrate the breadth of structural information that can be obtained from this approach, and the steps taken to elucidate the stoichiometry, topology, packing, dynamics, and shape of protein complexes. In addition, I illustrate the challenges that lie ahead, and the future directions toward which the field might be heading. (J Am Soc Mass Spectrom 2010, 21, 487-500)

Regulation of focal adhesion formation by a vinculin-Arp2/3 hybrid complex

“…The composition of the vinculin-containing protein complexes was then investigated by applying native MS and MS/MS approaches under conditions that preserve non-covalent interactions 46 . An electrospray mass spectrum revealed four different charge series (Fig.…”

Site-directed mutagenesis combined with oxidative methionine labeling for probing structural transitions of a membrane protein by mass spectrometry

“…However, the low-tomedium resolution obtainable by MS is highly valuable for systems that are difficult to study by other approaches. For example, the direct electrospray ionization (ESI)-MS analysis of large macromolecular assemblies provides insights into binding stoichiometries [3] and affinities [4]. The degree of multiple charging during ESI reflects the protein compactness and surface area in solution [5].…”

Top-down proteomic analysis of protein pharmaceuticals, mixtures of protein complexes, and ribosomal protein extracts by capillary zone electrophoresis-mass spectrometry

“…With the growing understanding that protein-protein interactions are directly correlated to biological activity, the domain of native MS has been expanding over the past several decades [91,92]. Analysis of intact proteins under native conditions allows for the detection of any noncovalent interactions and mitigates the incorporation of artificial modifications administered during sample preparation.…”