An integrative approach combining ion mobility mass spectrometry, X-ray crystallography, and nuclear magnetic resonance spectroscopy to study the conformational dynamics of (1)-antitrypsin upon ligand binding

作者：Nyon Mun Peak; Prentice Tanya; Day Jemma; Kirkpatrick John; Sivalingam Ganesh N; Levy Geraldine; Haq Imran; Irving James A; Lomas David A; Christodoulou John; Gooptu Bibek^*; Thalassinos Konstantinos

来源：Protein Science, 2015, 24(8): 1301-1312.

DOI：10.1002/pro.2706

• ion mobility mass spectrometry
• protein dynamics
• drug discovery
• 1-antitrypsin
• protein unfolding
• mass spectrometry
• methods
• nuclear magnetic resonance
• biomolecular
• X-ray crystallography

Native mass spectrometry (MS) methods permit the study of multiple protein species within solution equilibria, whereas ion mobility (IM)-MS can report on conformational behavior of specific states. We used IM-MS to study a conformationally labile protein ((1)-antitrypsin) that undergoes pathological polymerization in the context of point mutations. The folded, native state of the Z-variant remains highly polymerogenic in physiological conditions despite only minor thermodynamic destabilization relative to the wild-type variant. Various data implicate kinetic instability (conformational lability within a native state ensemble) as the basis of Z (1)-antitrypsin polymerogenicity. We show the ability of IM-MS to track such disease-relevant conformational behavior in detail by studying the effects of peptide binding on (1)-antitrypsin conformation and dynamics. IM-MS is, therefore, an ideal platform for the screening of compounds that result in therapeutically beneficial kinetic stabilization of native (1)-antitrypsin. Our findings are confirmed with high-resolution X-ray crystallographic and nuclear magnetic resonance spectroscopic studies of the same event, which together dissect structural changes from dynamic effects caused by peptide binding at a residue-specific level. IM-MS methods, therefore, have great potential for further study of biologically relevant thermodynamic and kinetic instability of proteins and provide rapid and multidimensional characterization of ligand interactions of therapeutic interest.

• 出版日期2015-8