Improving the Performance of a Quadrupole Time-of-Flight Instrument for Macromolecular Mass Spectrometry

• Published in: Analytical chemistry (Washington) Vol. 78; no. 21; pp. 7473 - 7483
• Main Authors: van den Heuvel, Robert H. H., van Duijn, Esther, Mazon, Hortense, Synowsky, Silvia A., Lorenzen, Kristina, Versluis, Cees, Brouns, Stan J. J., Langridge, Dave, van der Oost, John, Hoyes, John, Heck, Albert J. R.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-11-2006
• Subjects: Alcohol Oxidoreductases - chemistry; Analytical chemistry; assemblies; Chaperonin 10 - chemistry; Chaperonin 60 - chemistry; Chemistry; electrospray-ionization; escherichia-coli strain; esi-ms; Exact sciences and technology; gas-phase dissociation; General, instrumentation; groel; infrared radiative dissociation; ions; Mass spectrometry; Modifications; protein complexes; Proteins; Scientific apparatus & instruments; Spectrometric and optical methods; Tandem Mass Spectrometry - methods; vanillyl-alcohol oxidase; Performance evaluation; Stability; Instrumentation; Oligomer; Low frequency; Protein; Quadrupole spectrometer; High pressure; Multicomponent analysis; Time of flight method; Mass spectrometry MS/MS; Dissociation; Gas phase; Argon; Mass spectrometry; Molecule collision
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac061039a

We modified and optimized a first generation quadrupole time-of-flight (Q-TOF) 1 to perform tandem mass spectrometry on macromolecular protein complexes. The modified instrument allows isolation and subsequent dissociation of high-mass protein complexes through collisions with argon molecules. The modifications of the Q-TOF 1 include the introduction of (1) a flow-restricting sleeve around the first hexapole ion bridge, (2) a low-frequency ion-selecting quadrupole, (3) a high-pressure hexapole collision cell, (4) high-transmission grids in the multicomponent ion lenses, and (5) a low repetition rate pusher. Using these modifications, we demonstrate the experimental isolation of ions up to 12 800 mass-to-charge units and detection of product ions up to 38 150 Da, enabling the investigation of the gas-phase stability, protein complex topology, and quaternary structure of protein complexes. Some of the data reveal a so-far unprecedented new mechanism in gas-phase dissociation of protein oligomers whereby a tetramer complex dissociates into two dimers. These data add to the current debate whether gas-phase structures of protein complexes do retain some of the structural features of the corresponding species in solution. The presented low-cost modifications on a Q-TOF 1 instrument are of interest to everyone working in the fields of macromolecular mass spectrometry and more generic structural biology.