title: An integrative approach combining ion mobility mass spectrometry, X-ray crystallography, and nuclear magnetic resonance spectroscopy to study the conformational dynamics of α1 -antitrypsin upon ligand binding.
abstract: 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 (α1 -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 α1 -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 α1 -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 α1 -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.
authors.affiliation: Institute of Structural and Molecular Biology, Division of Biosciences, Division of Biosciences, University College London, London, WC1E 6BT, United Kingdom.
authors.forename: Mun Peak
authors.initials: MP
authors.lastname: Nyon
authors.affiliation: Institute of Structural and Molecular Biology, Division of Biosciences, Division of Biosciences, University College London, London, WC1E 6BT, United Kingdom.
authors.forename: Tanya
authors.initials: T
authors.lastname: Prentice
authors.affiliation: Institute of Structural and Molecular Biology, Division of Biosciences, Division of Biosciences, University College London, London, WC1E 6BT, United Kingdom.
authors.forename: Jemma
authors.initials: J
authors.lastname: Day
authors.affiliation: Institute of Structural and Molecular Biology, Division of Biosciences, Division of Biosciences, University College London, London, WC1E 6BT, United Kingdom.
authors.forename: John
authors.initials: J
authors.lastname: Kirkpatrick
authors.affiliation: Institute of Structural and Molecular Biology, Division of Biosciences, Division of Biosciences, University College London, London, WC1E 6BT, United Kingdom.
authors.forename: Ganesh N
authors.initials: GN
authors.lastname: Sivalingam
authors.affiliation: Institute of Structural and Molecular Biology, Division of Biosciences, Division of Biosciences, University College London, London, WC1E 6BT, United Kingdom.
authors.forename: Geraldine
authors.initials: G
authors.lastname: Levy
authors.affiliation: Wolfson Institute for Biomedical Research, Division of Medicine, University College London, London, WC1E 6BT, United Kingdom.
authors.forename: Imran
authors.initials: I
authors.lastname: Haq
authors.affiliation: Wolfson Institute for Biomedical Research, Division of Medicine, University College London, London, WC1E 6BT, United Kingdom.
authors.forename: James A
authors.initials: JA
authors.lastname: Irving
authors.affiliation: Wolfson Institute for Biomedical Research, Division of Medicine, University College London, London, WC1E 6BT, United Kingdom.
authors.forename: David A
authors.initials: DA
authors.lastname: Lomas
authors.affiliation: Institute of Structural and Molecular Biology, Division of Biosciences, Division of Biosciences, University College London, London, WC1E 6BT, United Kingdom.|Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, University of London, London, WC1E 7HX, United Kingdom.
authors.forename: John
authors.initials: J
authors.lastname: Christodoulou
authors.affiliation: Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, University of London, London, WC1E 7HX, United Kingdom.|Division of Asthma, Allergy and Lung Biology, King's College London, Guy's Hospital, London, SE1 9RT, United Kingdom.
authors.forename: Bibek
authors.initials: B
authors.lastname: Gooptu
authors.affiliation: Institute of Structural and Molecular Biology, Division of Biosciences, Division of Biosciences, University College London, London, WC1E 6BT, United Kingdom.|Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, University of London, London, WC1E 7HX, United Kingdom.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Thalassinos
mesh_terms: D018360:Crystallography, X-Ray; D055808:Drug Discovery; D006801:Humans; D008024:Ligands; D013058:Mass Spectrometry; D056004:Molecular Dynamics Simulation; D009154:Mutation; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology; D011485:Protein Binding; D011487:Protein Conformation; D013816:Thermodynamics; D000515:alpha 1-Antitrypsin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D008024:Ligands; D010455:Peptides; D000515:alpha 1-Antitrypsin
keywords: X-ray crystallography; biomolecular; drug discovery; ion mobility mass spectrometry; mass spectrometry/methods; nuclear magnetic resonance; protein dynamics; protein unfolding; α1-antitrypsin