{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,13]],"date-time":"2026-10-13T12:50:45Z","timestamp":1791895845725,"version":"4.3.4"},"reference-count":67,"publisher":"American Chemical Society (ACS)","issue":"40","license":[{"start":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T00:00:00Z","timestamp":1790553600000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-029"},{"start":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T00:00:00Z","timestamp":1790553600000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-037"},{"start":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T00:00:00Z","timestamp":1790553600000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-045"}],"funder":[{"DOI":"10.13039\/100000078","name":"Division of Materials Research","doi-asserted-by":"publisher","award":["DMR-2128556"],"award-info":[{"award-number":["DMR-2128556"]}],"id":[{"id":"10.13039\/100000078","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100023043","name":"State of Florida","doi-asserted-by":"publisher","award":["NA"],"award-info":[{"award-number":["NA"]}],"id":[{"id":"10.13039\/100023043","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,10,13]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Proton-transfer reaction (PTR) has emerged as a powerful tool for top-down proteomics. It can mitigate spectral congestion and improve the signal-to-noise ratio of electrospray ionization (ESI)-generated intact proteins. We hypothesized that charge removal during PTR of Coulombically unfolded, denatured ESI ions induces rapid gas-phase isomerization and refolding, producing charge-state-dependent conformers with altered fragmentation behavior. Here, we test this hypothesis by systematically comparing fragmentation patterns of three model proteins, apomyoglobin, apocalmodulin, and histone H1, with and without PTR using high-resolution top-down mass spectrometry. Highly charged precursor ions were isolated, subjected to PTR, fragmented, and benchmarked against ions of the same charge state generated directly from ESI; ions generated under native-like conditions were also examined. Quantitative analysis of assigned fragment ions and log2 fold-change heatmaps reveal distinct fragmentation patterns, with some regions showing protection from fragmentation, while others yield newly observed or substantially enhanced fragment ions. Notably, characteristic fragmentation signatures around proline and aspartic acid residues further demonstrate structural differences. These results show that protein relaxation after PTR generates different gas-phase ion structures than are formed during ESI and explain, alongside mobile proton theory, why charge reduction produces different sets of fragment ions in top-down MS\/MS, but can also yield fragmentation sites otherwise unavailable for higher-charged counterparts and the same charge states generated without PTR.<\/jats:p>","DOI":"10.1021\/acs.analchem.6c04013","type":"journal-article","created":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T17:01:49Z","timestamp":1790614909000},"page":"29299-29311","source":"Crossref","is-referenced-by-count":0,"title":["Proton-Transfer\nReactions Modulate Protein Ion Structure\nto Yield Altered Backbone Cleavage Pathways in Top-Down Mass Spectrometry"],"prefix":"10.1021","volume":"98","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8929-5479","authenticated-orcid":true,"given":"Marek","family":"Pola\u0301k","sequence":"first","affiliation":[{"name":"National High Magnetic Field Laboratory , , ,","place":["Tallahassee, Florida, United States, 32310"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8633-0251","authenticated-orcid":true,"given":"Lissa C.","family":"Anderson","sequence":"additional","affiliation":[{"name":"National High Magnetic Field Laboratory , , ,","place":["Tallahassee, Florida, United States, 32310"]},{"name":"Florida State University , , , ,","place":["Tallahassee, Florida, United States, 32306"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1926-0542","authenticated-orcid":true,"given":"Kristina","family":"H\u00e5kansson","sequence":"additional","affiliation":[{"name":"National High Magnetic Field Laboratory , , ,","place":["Tallahassee, Florida, United States, 32310"]},{"name":"Florida State University , , , ,","place":["Tallahassee, Florida, United States, 32306"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4272-2939","authenticated-orcid":true,"given":"Christopher L.","family":"Hendrickson","sequence":"additional","affiliation":[{"name":"National High Magnetic Field Laboratory , , ,","place":["Tallahassee, Florida, United States, 32310"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5324-4525","authenticated-orcid":true,"given":"Chad R.","family":"Weisbrod","sequence":"additional","affiliation":[{"name":"National High Magnetic Field Laboratory , , ,","place":["Tallahassee, Florida, United States, 32310"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2026,9,28]]},"reference":[{"issue":"1","key":"2026101308064401800_cit1","doi-asserted-by":"publisher","first-page":"213","DOI":"10.1021\/ac4039306","article-title":"Mass Spectrometry Methods for Studying\nStructure and Dynamics of Biological Macromolecules","volume":"86","author":"Konermann","year":"2014","journal-title":"Anal. Chem."},{"issue":"10","key":"2026101308064401800_cit2","doi-asserted-by":"publisher","first-page":"4355","DOI":"10.1021\/acs.chemrev.9b00815","article-title":"Mass Spectrometry-Based Protein Footprinting\nfor Higher-Order Structure Analysis: Fundamentals and Applications","volume":"120","author":"Liu","year":"2020","journal-title":"Chem. Rev."},{"issue":"7","key":"2026101308064401800_cit3","doi-asserted-by":"publisher","first-page":"595","DOI":"10.1038\/s41592-019-0459-y","article-title":"Recommendations for Performing, Interpreting and Reporting\nHydrogen Deuterium Exchange Mass Spectrometry (HDX-MS) Experiments","volume":"16","author":"Masson","year":"2019","journal-title":"Nat. Methods"},{"issue":"8","key":"2026101308064401800_cit4","doi-asserted-by":"publisher","first-page":"4792","DOI":"10.1039\/C5SC04196A","article-title":"Cross-Linking\nand Other Structural Proteomics Techniques: How Chemistry Is Enabling\nMass Spectrometry Applications in Structural Biology","volume":"7","author":"Leitner","year":"2016","journal-title":"Chem. Sci."},{"issue":"8","key":"2026101308064401800_cit5","doi-asserted-by":"publisher","first-page":"7952","DOI":"10.1021\/acs.chemrev.1c00356","article-title":"Integration of Mass Spectrometry\nData for Structural Biology","volume":"122","author":"Britt","year":"2022","journal-title":"Chem. Rev."},{"key":"2026101308064401800_cit6","doi-asserted-by":"publisher","first-page":"377","DOI":"10.1016\/j.trechm.2024.05.002","article-title":"Mass spectrometry-based methods for characterizing\ntransient protein\u2013protein interactions","volume":"6","author":"Veale","year":"2024","journal-title":"Trends In Chemistry. Cell"},{"issue":"8","key":"2026101308064401800_cit7","doi-asserted-by":"publisher","first-page":"2081","DOI":"10.1021\/jasms.0c00482","article-title":"Improved Protein and\nPTM Characterization with a Practical Electron-Based Fragmentation\non Q-TOF Instruments","volume":"32","author":"Beckman","year":"2021","journal-title":"J. Am. Soc. Mass Spectrom."},{"issue":"C","key":"2026101308064401800_cit8","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/S0003-2670(00)84589-4","article-title":"Tamdem\nQuadrupole Fourier Transform Mass Spectrometry","volume":"225","author":"Hunt","year":"1989","journal-title":"Anal. Chim. Acta"},{"issue":"8","key":"2026101308064401800_cit9","doi-asserted-by":"publisher","first-page":"548","DOI":"10.1039\/c39870000548","article-title":"Peptide Sequence\nAnalysis by Laser\nPhotodissociation Fourier Transform Mass Spectrometry","author":"Hunt","year":"1987","journal-title":"J. Chem. Soc., Chem. Commun."},{"issue":"34","key":"2026101308064401800_cit10","doi-asserted-by":"publisher","first-page":"12646","DOI":"10.1021\/ja4029654","article-title":"Complete Protein Characterization Using Top-down Mass\nSpectrometry and Ultraviolet Photodissociation","volume":"135","author":"Shaw","year":"2013","journal-title":"J. Am. Chem. Soc."},{"issue":"7","key":"2026101308064401800_cit11","doi-asserted-by":"publisher","first-page":"2193","DOI":"10.1073\/pnas.0607084104","article-title":"Analysis of Phosphorylation Sites on Proteins from\nSaccharomyces Cerevisiae by Electron Transfer Dissociation (ETD) Mass\nSpectrometry","volume":"104","author":"Chi","year":"2007","journal-title":"Proc. Natl. Acad. Sci. U. S. A."},{"issue":"2","key":"2026101308064401800_cit12","doi-asserted-by":"publisher","first-page":"477","DOI":"10.1021\/ac061457f","article-title":"Supplemental Activation Method for High-Efficiency\nElectron-Transfer Dissociation of Doubly Protonated Peptide Precursors","volume":"79","author":"Swaney","year":"2007","journal-title":"Anal. Chem."},{"issue":"7","key":"2026101308064401800_cit13","doi-asserted-by":"publisher","first-page":"2653","DOI":"10.1021\/acs.jproteome.7b00249","article-title":"Activated Ion-Electron Transfer Dissociation\nEnables Comprehensive Top-Down Protein Fragmentation","volume":"16","author":"Riley","year":"2017","journal-title":"J. Proteome Res."},{"issue":"7","key":"2026101308064401800_cit14","doi-asserted-by":"publisher","first-page":"2386","DOI":"10.1021\/acs.jproteome.4c00072","article-title":"Electron Capture vs Transfer Dissociation for Site\nDetermination of Tryptic Peptide Tyrosine Sulfation: Direct Detection\nof Fibrinogen Sulfation Sites and Identification of Novel Isobaric\nInterferences","volume":"23","author":"Youssef","year":"2024","journal-title":"J. Proteome Res."},{"issue":"2","key":"2026101308064401800_cit15","doi-asserted-by":"publisher","first-page":"433","DOI":"10.1021\/ja9630046","article-title":"Protein Molecular Mass to 1 Da by\n13C, 15N Double-Depletion and FT-ICR Mass Spectrometry","volume":"119","author":"Marshall","year":"1997","journal-title":"J. Am. Chem. Soc."},{"issue":"3","key":"2026101308064401800_cit16","doi-asserted-by":"publisher","first-page":"700","DOI":"10.1021\/jasms.9b00119","article-title":"Isotope Depletion\nMass Spectrometry (ID-MS) for Accurate\nMass Determination and Improved Top-Down Sequence Coverage of Intact\nProteins","volume":"31","author":"Gallagher","year":"2020","journal-title":"J. Am. Soc. Mass Spectrom."},{"issue":"31","key":"2026101308064401800_cit17","doi-asserted-by":"publisher","first-page":"7390","DOI":"10.1021\/ja9611755","article-title":"Ion\/Ion Reactions in the Gas Phase: Proton Transfer\nReactions Involving Multiply-Charged Proteins","volume":"118","author":"Stephenson","year":"1996","journal-title":"J. Am. Chem. Soc."},{"issue":"22","key":"2026101308064401800_cit18","doi-asserted-by":"publisher","first-page":"4026","DOI":"10.1021\/ac9605657","article-title":"Ion\/Ion Proton Transfer\nReactions for Protein Mixture\nAnalysis","volume":"68","author":"Stephenson","year":"1996","journal-title":"Anal. Chem."},{"issue":"6","key":"2026101308064401800_cit19","doi-asserted-by":"publisher","first-page":"1198","DOI":"10.1021\/ac9710137","article-title":"Ion\/Ion Proton-Transfer Kinetics:\nImplications for Analysis of Ions Derived from Electrospray of Protein\nMixtures","volume":"70","author":"McLuckey","year":"1998","journal-title":"Anal. Chem."},{"issue":"17","key":"2026101308064401800_cit20","doi-asserted-by":"publisher","first-page":"3533","DOI":"10.1021\/ac9802832","article-title":"Simplification of\nProduct Ion Spectra Derived from\nMultiply Charged Parent Ions via Ion\/Ion Chemistry","volume":"70","author":"Stephenson","year":"1998","journal-title":"Anal. Chem."},{"issue":"1","key":"2026101308064401800_cit21","doi-asserted-by":"publisher","first-page":"310","DOI":"10.1021\/ac0515778","article-title":"Parallel\nIon Parking of Protein Mixtures","volume":"78","author":"Chrisman","year":"2006","journal-title":"Anal. Chem."},{"issue":"10","key":"2026101308064401800_cit22","doi-asserted-by":"publisher","first-page":"3411","DOI":"10.1021\/ac0503613","article-title":"Parallel Ion Parking: Improving Conversion\nof Parents to First-Generation Products in Electron Transfer Dissociation","volume":"77","author":"Chrisman","year":"2005","journal-title":"Anal. Chem."},{"issue":"26","key":"2026101308064401800_cit23","doi-asserted-by":"publisher","first-page":"9119","DOI":"10.1021\/acs.analchem.1c00847","article-title":"Advanced Strategies\nfor Proton-Transfer Reactions Coupled with Parallel Ion Parking on\na 21 T FT-ICR MS for Intact Protein Analysis","volume":"93","author":"Weisbrod","year":"2021","journal-title":"Anal. Chem."},{"issue":"10","key":"2026101308064401800_cit24","doi-asserted-by":"publisher","first-page":"2163","DOI":"10.1007\/s13361-019-02290-8","article-title":"Ion-Ion Proton Transfer\nand Parallel\nIon Parking for the Analysis of Mixtures of Intact Proteins on a Modified\nOrbitrap Mass Analyzer","volume":"30","author":"Ugrin","year":"2019","journal-title":"J. Am. Soc. Mass Spectrom."},{"issue":"47","key":"2026101308064401800_cit25","doi-asserted-by":"publisher","first-page":"15728","DOI":"10.1021\/acs.analchem.1c03652","article-title":"Improved Sequence Analysis of Intact Proteins by Parallel\nIon Parking during Electron Transfer Dissociation","volume":"93","author":"Duselis","year":"2021","journal-title":"Anal. Chem."},{"issue":"30","key":"2026101308064401800_cit26","doi-asserted-by":"publisher","first-page":"9581","DOI":"10.1021\/jacs.6b04282","article-title":"Folding\nof Protein Ions in the Gas\nPhase after Cation-to-Anion Proton-Transfer Reactions","volume":"138","author":"Laszlo","year":"2016","journal-title":"J. Am. Chem. Soc."},{"issue":"5","key":"2026101308064401800_cit27","doi-asserted-by":"publisher","first-page":"399","DOI":"10.1002\/rcm.8347","article-title":"The Effects\nof Solution Additives and Gas-phase Modifiers on the Molecular Environment\nand Conformational Space of Common Heme Proteins","volume":"33","author":"Butcher","year":"2019","journal-title":"Rapid Commun. Mass Spectrom."},{"issue":"18","key":"2026101308064401800_cit28","doi-asserted-by":"publisher","first-page":"3667","DOI":"10.1021\/acs.jpcb.0c01934","article-title":"Gas Phase\nProtein Folding Triggered by Proton Stripping\nGenerates Inside-Out Structures: A Molecular Dynamics Simulation Study","volume":"124","author":"Sever","year":"2020","journal-title":"J. Phys. Chem. B"},{"issue":"43","key":"2026101308064401800_cit29","doi-asserted-by":"publisher","first-page":"9947","DOI":"10.1021\/acs.jpcb.8b08427","article-title":"Effects of Charge\nState on the Structures of Serum\nAlbumin Ions in the Gas Phase: Insights from Cation-to-Anion Proton-Transfer\nReactions, Ion Mobility, and Mass Spectrometry","volume":"122","author":"Gadzuk-Shea","year":"2018","journal-title":"J. Phys. Chem. B"},{"issue":"21","key":"2026101308064401800_cit30","doi-asserted-by":"publisher","first-page":"9720","DOI":"10.1021\/acs.jctc.4c00288","article-title":"Elucidating Protein Structures in\nthe Gas Phase: Traversing Configuration Space with Biasing Methods","volume":"20","author":"Gandhi","year":"2024","journal-title":"J. Chem. Theory Comput."},{"issue":"24","key":"2026101308064401800_cit31","doi-asserted-by":"publisher","first-page":"11710","DOI":"10.1021\/ac403115c","article-title":"Novel Parallelized\nQuadrupole\/Linear Ion Trap\/Orbitrap Tribrid Mass Spectrometer Improving\nProteome Coverage and Peptide Identification Rates","volume":"85","author":"Senko","year":"2013","journal-title":"Anal. Chem."},{"issue":"9","key":"2026101308064401800_cit32","doi-asserted-by":"publisher","first-page":"2334","DOI":"10.1021\/jasms.1c00062","article-title":"Sequential\nIon-Ion Reactions for\nEnhanced Gas-Phase Sequencing of Large Intact Proteins in a Tribrid\nOrbitrap Mass Spectrometer","volume":"32","author":"Kline","year":"2021","journal-title":"J. Am. Soc. Mass\nSpectrom."},{"issue":"28","key":"2026101308064401800_cit33","doi-asserted-by":"publisher","first-page":"6463","DOI":"10.1007\/s00216-024-05534-z","article-title":"Towards a Universal Method for Middle-down Analysis\nof Antibodies via Proton Transfer Charge Reduction\u2500Orbitrap\nMass Spectrometry","volume":"416","author":"Oates","year":"2024","journal-title":"Anal. Bioanal. Chem."},{"issue":"46","key":"2026101308064401800_cit34","doi-asserted-by":"publisher","first-page":"18483","DOI":"10.1021\/acs.analchem.4c03872","article-title":"Enhanced Payload Localization in Antibody-Drug Conjugates\nUsing a Middle-Down Mass Spectrometry Approach with Proton Transfer\nCharge Reduction","volume":"96","author":"Lieu","year":"2024","journal-title":"Anal. Chem."},{"issue":"12","key":"2026101308064401800_cit35","doi-asserted-by":"publisher","first-page":"1399","DOI":"10.1002\/1096-9888(200012)35:12&lt;1399::AID-JMS86&gt;3.0.CO;2-R","article-title":"Mobile and Localized\nProtons: A Framework for Understanding Peptide Dissociation","volume":"35","author":"Wysocki","year":"2000","journal-title":"J. Mass Spectrom."},{"issue":"6","key":"2026101308064401800_cit36","doi-asserted-by":"publisher","first-page":"1203","DOI":"10.1007\/s13361-017-1635-x","article-title":"Defining\nGas-Phase Fragmentation Propensities of Intact Proteins During Native\nTop-Down Mass Spectrometry","volume":"28","author":"Haverland","year":"2017","journal-title":"J. Am. Soc. Mass\nSpectrom."},{"issue":"4","key":"2026101308064401800_cit37","doi-asserted-by":"publisher","first-page":"704","DOI":"10.1007\/s13361-019-02146-1","article-title":"Top-Down\nAnalysis\nof Proteins in Low Charge States","volume":"30","author":"Bashyal","year":"2019","journal-title":"J. Am. Soc.\nMass Spectrom."},{"issue":"14","key":"2026101308064401800_cit38","doi-asserted-by":"publisher","first-page":"6750","DOI":"10.1021\/jacs.0c01076","article-title":"Pervasive Charge Solvation Permeates\nNative-like Protein\nIons and Dramatically Influences Top-down Sequencing Data","volume":"142","author":"Polasky","year":"2020","journal-title":"J. Am. Chem. Soc."},{"issue":"26","key":"2026101308064401800_cit39","doi-asserted-by":"publisher","first-page":"9528","DOI":"10.1073\/pnas.0402700101","article-title":"Peptide and Protein Sequence Analysis\nby Electron Transfer\nDissociation Mass Spectrometry","volume":"101","author":"Syka","year":"2004","journal-title":"Proc. Natl.\nAcad. Sci. U. S. A."},{"issue":"3\u20134","key":"2026101308064401800_cit40","doi-asserted-by":"publisher","first-page":"201","DOI":"10.1016\/S0009-2614(02)00149-5","article-title":"Dissociative\nCapture of Hot (3\u201313 EV) Electrons by Polypeptide Polycations:\nAn Efficient Process Accompanied by Secondary Fragmentation","volume":"356","author":"Kjeldsen","year":"2002","journal-title":"Chem. Phys. Lett."},{"issue":"22","key":"2026101308064401800_cit41","doi-asserted-by":"publisher","first-page":"6407","DOI":"10.1021\/ja012267j","article-title":"Detailed\nUnfolding and Folding of Gaseous Ubiquitin Ions Characterized by Electron\nCapture Dissociation","volume":"124","author":"Breuker","year":"2002","journal-title":"J. Am. Chem. Soc."},{"issue":"20","key":"2026101308064401800_cit42","doi-asserted-by":"publisher","first-page":"10711","DOI":"10.1021\/acs.analchem.7b01581","article-title":"Native Electron Capture Dissociation\nMaps to Iron-Binding Channels in Horse Spleen Ferritin","volume":"89","author":"Skinner","year":"2017","journal-title":"Anal. Chem."},{"issue":"12","key":"2026101308064401800_cit43","doi-asserted-by":"publisher","first-page":"2273","DOI":"10.1016\/j.jasms.2009.08.019","article-title":"Electron\nCapture Dissociation Product\nIon Abundances at the X Amino Acid in RAAAA-X-AAAAK Peptides Correlate\nwith Amino Acid Polarity and Radical Stability","volume":"20","author":"Vorobyev","year":"2009","journal-title":"J. Am. Soc. Mass Spectrom."},{"issue":"1","key":"2026101308064401800_cit44","doi-asserted-by":"publisher","first-page":"113","DOI":"10.1016\/j.jasms.2006.09.008","article-title":"Hydrogen Rearrangement\nto and from Radical z Fragments in Electron Capture Dissociation of\nPeptides","volume":"18","author":"Savitski","year":"2007","journal-title":"J. Am. Soc. Mass Spectrom."},{"issue":"6","key":"2026101308064401800_cit45","doi-asserted-by":"publisher","first-page":"753","DOI":"10.1016\/j.jasms.2008.03.007","article-title":"Electron Capture\/Transfer versus\nCollisionally Activated\/Induced Dissociations: Solo or Duet?","volume":"19","author":"Zubarev","year":"2008","journal-title":"J. Am. Soc. Mass Spectrom."},{"issue":"24","key":"2026101308064401800_cit46","doi-asserted-by":"publisher","first-page":"9540","DOI":"10.1021\/ac202327r","article-title":"Statistical Analysis\nof Electron Transfer Dissociation\nPairwise Fragmentation Patterns","volume":"83","author":"Li","year":"2011","journal-title":"Anal. Chem."},{"issue":"9","key":"2026101308064401800_cit47","doi-asserted-by":"publisher","first-page":"4334","DOI":"10.1021\/pr200156b","article-title":"Improving SRM Assay Development:\nA Global Comparison between Triple Quadrupole, Ion Trap, and Higher\nEnergy CID Peptide Fragmentation Spectra","volume":"10","author":"De Graaf","year":"2011","journal-title":"J.\nProteome Res."},{"issue":"4","key":"2026101308064401800_cit48","doi-asserted-by":"publisher","first-page":"1218","DOI":"10.1021\/ac051622b","article-title":"Ion Trap versus Low-Energy Beam-Type\nCollision-Induced Dissociation of Protonated Ubiquitin Ions","volume":"78","author":"Xia","year":"2006","journal-title":"Anal. Chem."},{"issue":"10","key":"2026101308064401800_cit49","doi-asserted-by":"publisher","first-page":"1851","DOI":"10.1016\/j.jasms.2009.06.010","article-title":"Collision Induced\nUnfolding of Protein Ions in the\nGas Phase Studied by Ion Mobility-Mass Spectrometry: The Effect of\nLigand Binding on Conformational Stability","volume":"20","author":"Hopper","year":"2009","journal-title":"J. Am. Soc. Mass Spectrom."},{"issue":"1","key":"2026101308064401800_cit50","doi-asserted-by":"publisher","first-page":"646","DOI":"10.1016\/j.ijms.2014.07.012","article-title":"An IMS\u2013IMS\nThreshold Method for Semi-Quantitative\nDetermination of Activation Barriers: Interconversion of Proline Cis\u2194trans\nForms in Triply Protonated Bradykinin","volume":"377","author":"Pierson","year":"2015","journal-title":"Int.\nJ. Mass Spectrom."},{"issue":"23","key":"2026101308064401800_cit51","doi-asserted-by":"publisher","first-page":"5114","DOI":"10.1021\/acs.jpcb.6b03035","article-title":"Collision-Induced\nDissociation of Electrosprayed Protein Complexes: An All-Atom Molecular\nDynamics Model with Mobile Protons","volume":"120","author":"Popa","year":"2016","journal-title":"J. Phys.\nChem. B"},{"issue":"9","key":"2026101308064401800_cit52","doi-asserted-by":"publisher","first-page":"1974","DOI":"10.1021\/jasms.0c00242","article-title":"Probing\nthe Stability of Proline Cis\/Trans Isomers in the Gas Phase with Ultraviolet\nPhotodissociation","volume":"31","author":"Silzel","year":"2020","journal-title":"J. Am. Soc. 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