Fourier Transform-Ion Cyclotron Resonance Mass Spectrometry as a Platform for Characterizing Multimeric Membrane Protein Complexes

Journal Article · Mon Jan 15 04:00:00 EST 2018 · Journal of the American Society for Mass Spectrometry

DOI:https://doi.org/10.1007/S13361-017-1799-4· OSTI ID:22776812

Lippens, Jennifer L. ^[1]; Nshanian, Michael ^[2]; Spahr, Chris ^[1]; Egea, Pascal F. ^[3]; Campuzano, Iain D. G., ^[1]

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1. Amgen, Discovery Attribute Sciences (United States)
2. University of California-Los Angeles, Department of Chemistry and Biochemistry (United States)
3. University of California-Los Angeles, Department of Biological Chemistry and Molecular Biology Institute (United States)

Membrane protein characterization is consistently hampered by challenges with expression, purification, and solubilization. Among several biophysical techniques employed for their characterization, native-mass spectrometry (MS) has emerged as a powerful tool for the analysis of membrane proteins and complexes. Here, two MS platforms, the FT-ICR and Q-ToF, have been explored to analyze the homotetrameric water channel protein, AquaporinZ (AqpZ), under non-denaturing conditions. This 97 kDa membrane protein complex can be readily liberated from the octylglucoside (OG) detergent micelle under a range of instrument conditions on both MS platforms. Increasing the applied collision energy of the FT-ICR collision cell yielded varying degrees of tetramer (97 kDa) liberation from the OG micelles, as well as dissociation into the trimeric (72 kDa) and monomeric (24 kDa) substituents. Tandem-MS on the Q-ToF yielded higher intensity tetramer signal and, depending on the m/z region selected, the observed monomer signal varied in intensity. Precursor ion selection of an m/z range above the expected protein signal distribution, followed by mild collisional activation, is able to efficiently liberate AqpZ with a high S/N ratio. The tetrameric charge state distribution obtained on both instruments demonstrated superpositioning of multiple proteoforms due to varying degrees of N-terminal formylation. .

• OSTI ID: 22776812
• Journal Information: Journal of the American Society for Mass Spectrometry, Journal Name: Journal of the American Society for Mass Spectrometry Journal Issue: 1 Vol. 29; ISSN 1044-0305; ISSN JAMSEF
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
CHARGE STATES
DISSOCIATION
DISTRIBUTION
FOURIER TRANSFORMATION
ION CYCLOTRON-RESONANCE
MASS SPECTROSCOPY
MEMBRANE PROTEINS
MONOMERS
SIGNALS
TOOLS