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van Wonderen JH, Crack JC, Edwards MJ, Clarke TA, Saalbach G, Martins C, Butt JN. Liquid-chromatography mass spectrometry describes post-translational modification of Shewanella outer membrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184221. [PMID: 37673350 DOI: 10.1016/j.bbamem.2023.184221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 08/09/2023] [Accepted: 08/30/2023] [Indexed: 09/08/2023]
Abstract
Electrogenic bacteria deliver excess respiratory electrons to externally located metal oxide particles and electrodes. The biochemical basis for this process is arguably best understood for species of Shewanella where the integral membrane complex termed MtrCAB is key to electron transfer across the bacterial outer membranes. A crystal structure was recently resolved for MtrCAB from S. baltica OS185. However, X-ray diffraction did not resolve the N-terminal residues so that the lipidation status of proteins in the mature complex was poorly described. Here we report liquid chromatography mass spectrometry revealing the intact mass values for all three proteins in the MtrCAB complexes purified from Shewanella oneidensis MR-1 and S. baltica OS185. The masses of MtrA and MtrB are consistent with both proteins being processed by Signal Peptidase I and covalent attachment of ten c-type hemes to MtrA. The mass of MtrC is most reasonably interpreted as arising from protein processed by Signal Peptidase II to produce a diacylated lipoprotein containing ten c-type hemes. Our two-step protocol for liquid-chromatography mass spectrometry used a reverse phase column to achieve on-column detergent removal prior to gradient protein resolution and elution. We envisage the method will be capable of simultaneously resolving the intact mass values for multiple proteins in other membrane protein complexes.
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Affiliation(s)
- Jessica H van Wonderen
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
| | - Jason C Crack
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Marcus J Edwards
- School of Biological Sciences, University of East Anglia, , Norwich Research Park, Norwich NR4 7TJ, UK; School of Life Sciences, University of Essex, Colchester CO4 3SQ, UK
| | - Thomas A Clarke
- School of Biological Sciences, University of East Anglia, , Norwich Research Park, Norwich NR4 7TJ, UK
| | - Gerhard Saalbach
- Proteomics Facility, The John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Carlo Martins
- Proteomics Facility, The John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Julea N Butt
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK; School of Biological Sciences, University of East Anglia, , Norwich Research Park, Norwich NR4 7TJ, UK.
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2
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Brown KA, Morris R, Eckhardt SJ, Ge Y, Gellman SH. Phosphorylation Sites of the Gastric Inhibitory Polypeptide Receptor (GIPR) Revealed by Trapped-Ion-Mobility Spectrometry Coupled to Time-of-Flight Mass Spectrometry (TIMS-TOF MS). J Am Chem Soc 2023; 145:28030-28037. [PMID: 38091482 PMCID: PMC10842860 DOI: 10.1021/jacs.3c09078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
The gastric inhibitory polypeptide receptor (GIPR), a G protein-coupled receptor (GPCR) that regulates glucose metabolism and insulin secretion, is a target for the development of therapeutic agents to address type 2 diabetes and obesity. Signal transduction processes mediated by GPCR activation typically result in receptor phosphorylation, but very little is known about GIPR phosphorylation. Mass spectrometry (MS) is a powerful tool for detecting phosphorylation and other post-translational modifications of proteins and for identifying modification sites. However, applying MS methods to GPCRs is challenging because the native expression levels are low and the hydrophobicity of these proteins complicates isolation and enrichment. Here we use a widely available technique, trapped-ion-mobility spectrometry coupled to time-of-flight mass spectrometry (TIMS-TOF MS), to characterize the phosphorylation status of the GIPR. We identified eight serine residues that are phosphorylated, one in an intracellular loop and the remainder in the C-terminal domain. Stimulation with the native agonist GIP enhanced phosphorylation at four of these sites. For comparison, we evaluated tirzepatide (TZP), a dual agonist of the glucagon-like peptide-1 (GLP-1) receptor and the GIPR that has recently been approved for the treatment of type 2 diabetes. Stimulation with TZP enhanced phosphorylation at the same four sites that were enhanced with GIP; however, TZP also enhanced phosphorylation at a fifth site that is unique to this synthetic agonist. This work establishes an important and accessible tool for the characterization of signal transduction via the GIPR and reveals an unanticipated functional difference between GIP and TZP.
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Affiliation(s)
- Kyle A. Brown
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
| | - Rylie Morris
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
| | - Samantha J. Eckhardt
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
| | - Ying Ge
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin, 53705, USA
- Human Proteomics Program, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, 53705, USA
| | - Samuel H. Gellman
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
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Campuzano IDG. A Research Journey: Over a Decade of Denaturing and Native-MS Analyses of Hydrophobic and Membrane Proteins in Amgen Therapeutic Discovery. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:2413-2431. [PMID: 37643331 DOI: 10.1021/jasms.3c00175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Membrane proteins and associated complexes currently comprise the majority of therapeutic targets and remain among the most challenging classes of proteins for analytical characterization. Through long-term strategic collaborations forged between industrial and academic research groups, there has been tremendous progress in advancing membrane protein mass spectrometry (MS) analytical methods and their concomitant application to Amgen therapeutic project progression. Herein, I will describe a detailed and personal account of how electrospray ionization (ESI) native mass spectrometry (nMS), ion mobility-MS (IM-MS), reversed phase liquid chromatographic mass spectrometry (RPLC-MS), high-throughput solid phase extraction mass spectrometry, and matrix-assisted laser desorption ionization mass spectrometry methods were developed, optimized, and validated within Amgen Research, and importantly, how these analytical methods were applied for membrane and hydrophobic protein analyses and ultimately therapeutic project support and progression. Additionally, I will discuss all the highly important and productive collaborative efforts, both internal Amgen and external academic, which were key in generating the samples, methods, and associated data described herein. I will also describe some early and previously unpublished nano-ESI (nESI) native-MS data from Amgen Research and the highly productive University of California Los Angeles (UCLA) collaboration. I will also present previously unpublished examples of real-life Amgen biotherapeutic membrane protein projects that were supported by all the MS (and IM) analytical techniques described herein. I will start by describing the initial nESI nMS experiments performed at Amgen in 2011 on empty nanodisc molecules, using a quadrupole time-of-flight MS, and how these experiments progressed on to the 15 Tesla Fourier transform ion cyclotron resonance MS at UCLA. Then described are monomeric and multimeric membrane protein data acquired in both nESI nMS and tandem-MS modes, using multiple methods of ion activation, resulting in dramatic spectral simplification. Also described is how we investigated the far less established and less published subject, that is denaturing RPLC-MS analysis of membrane proteins, and how we developed a highly robust and reproducible RPLC-MS method capable of effective separation of membrane proteins differing in only the presence or absence of an N-terminal post translational modification. Also described is the evolution of the aforementioned RPLC-MS method into a high-throughput solid phase extraction MS method. Finally, I will give my opinion on key developments and how the area of nMS of membrane proteins needs to evolve to a state where it can be applied within the biopharmaceutical research environment for routine therapeutic project support.
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Affiliation(s)
- Iain D G Campuzano
- Amgen Research, Center for Research Acceleration by Digital Innovation, Molecular Analytics, Thousand Oaks, California 91320, United States
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4
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Seeing the complete picture: proteins in top-down mass spectrometry. Essays Biochem 2022; 67:283-300. [PMID: 36468679 DOI: 10.1042/ebc20220098] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 11/11/2022] [Accepted: 11/14/2022] [Indexed: 12/12/2022]
Abstract
Abstract
Top-down protein mass spectrometry can provide unique insights into protein sequence and structure, including precise proteoform identification and study of protein–ligand and protein–protein interactions. In contrast with the commonly applied bottom-up approach, top-down approaches do not include digestion of the protein of interest into small peptides, but instead rely on the ionization and subsequent fragmentation of intact proteins. As such, it is fundamentally the only way to fully characterize the composition of a proteoform. Here, we provide an overview of how a top-down protein mass spectrometry experiment is performed and point out recent applications from the literature to the reader. While some parts of the top-down workflow are broadly applicable, different research questions are best addressed with specific experimental designs. The most important divide is between studies that prioritize sequence information (i.e., proteoform identification) versus structural information (e.g., conformational studies, or mapping protein–protein or protein–ligand interactions). Another important consideration is whether to work under native or denaturing solution conditions, and the overall complexity of the sample also needs to be taken into account, as it determines whether (chromatographic) separation is required prior to MS analysis. In this review, we aim to provide enough information to support both newcomers and more experienced readers in the decision process of how to answer a potential research question most efficiently and to provide an overview of the methods that exist to answer these questions.
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Campuzano IDG, Pelegri-O'Day EM, Srinivasan N, Lippens JL, Egea P, Umeda A, Aral J, Zhang T, Laganowsky A, Netirojjanakul C. High-Throughput Mass Spectrometry for Biopharma: A Universal Modality and Target Independent Analytical Method for Accurate Biomolecule Characterization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:2191-2198. [PMID: 36206542 DOI: 10.1021/jasms.2c00138] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Reversed-phase liquid chromatographic mass spectrometry (rpLC-MS) is a universal, platformed, and essential analytical technique within pharmaceutical and biopharmaceutical research. Typical rpLC method gradient times can range from 5 to 20 min. As monoclonal antibody (mAb) therapies continue to evolve and bispecific antibodies (BsAbs) become more established, research stage engineering panels will clearly evolve in size. Therefore, high-throughput (HT) MS and automated deconvolution methods are key for success. Additionally, newer therapeutics such as bispecific T-cell engagers and nucleic acid-based modalities will also require MS characterization. Herein, we present a modality and target agnostic HT solid-phase extraction (SPE) MS method that affords the analysis of a 96-well plate in 41.4 min, compared to the traditional rpLC-MS method that would typically take 14.4 h. The described method can accurately determine the molecular weights for monodispersed and highly polydispersed biotherapeutic species and membrane proteins; determine levels of glycosylation, glycation, and formylation; detect levels of chain mispairing; and determine accurate drug-to-antibody ratio values.
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Affiliation(s)
- Iain D G Campuzano
- Amgen Research, Molecular Analytics, Biologics Therapeutic Discovery, 1 Amgen Center Drive, Thousand Oaks, California91320, United States
| | - Emma M Pelegri-O'Day
- Amgen Research, Molecular Analytics, Biologics Therapeutic Discovery, 1 Amgen Center Drive, Thousand Oaks, California91320, United States
| | - Nithya Srinivasan
- Amgen Research, Molecular Analytics, Biologics Therapeutic Discovery, 1 Amgen Center Drive, Thousand Oaks, California91320, United States
| | - Jennifer L Lippens
- Pivotal Attribute Sciences, Process Development, 1 Amgen Center Drive, Thousand Oaks, California91320, United States
| | - Pascal Egea
- Department of Biological Chemistry, University of California─Los Angeles, Los Angeles, California90095, United States
| | - Aiko Umeda
- Amgen Research, Platform Engineering, Biologics Therapeutic Discovery, 1 Amgen Center Drive, Thousand Oaks, California91320, United States
| | - Jennifer Aral
- Amgen Research, Platform Engineering, Biologics Therapeutic Discovery, 1 Amgen Center Drive, Thousand Oaks, California91320, United States
| | - Tianqi Zhang
- Department of Chemistry, Texas A&M University, College Station, Texas77843, United States
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, College Station, Texas77843, United States
| | - Chawita Netirojjanakul
- Amgen Research, Platform Engineering, Biologics Therapeutic Discovery, 1 Amgen Center Drive, Thousand Oaks, California91320, United States
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6
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Fan T, Jing S, Zhang H, Yang X, Jin G, Tao Y. Localization, purification, and characterization of a novel β-glucosidase from Hanseniaspora uvarum Yun268. J Food Sci 2022; 87:886-894. [PMID: 35142373 DOI: 10.1111/1750-3841.16068] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 12/22/2021] [Accepted: 01/12/2022] [Indexed: 11/28/2022]
Abstract
β-Glucosidase is a key enzyme that hydrolyzes nonvolatile glycosylated precursors of aroma compounds and enhances the organoleptic quality of wines. In this study, a novel β-glucosidase from Hanseniaspora uvarum Yun268 was localized, purified, and characterized. Results indicated that β-glucosidase activity was mainly distributed within the cells. After purification via ammonium sulfate precipitation combined with chromatography, β-glucosidase specific activity increased 8.36 times, and the activity recovery was 56.90%. The enzyme had a molecular mass of 74.22 kDa. It has a Michaelis constant (Km ) of 0.65 mmol/L, and a maximum velocity (Vmax ) of 5.1 nmol/min under optimum conditions; and Km of 0.94 mmol/L, and Vmax of 2.8 nmol/min under typical winemaking conditions. It exhibited the highest activity at 50°C and pH 5.0 and was stable at a temperature range of 20-80°C and pH range of 3.0-8.0. The enzyme has good tolerance to Fe3+ , especially maintaining 93.68% of its activity with 10 mmol/L of Fe3+ . Ethanol (<20%) and glucose (<150 g/L) inhibited its activity only slightly. Therefore, β-glucosidase from H. uvarum Yun268 has excellent biochemical properties and a good application potential in winemaking. PRACTICAL APPLICATION: Winemaking is a biotechnological process in which exogenous β-glucosidase is used to overcome the deficiency of endogenous β-glucosidase activity in grapes. By localizing, purifying, and characterizing of β-glucosidase from Hanseniaspora uvarum Yun268, it is expected to reveal its physical and chemical characteristics to evaluate its oenological properties in winemaking. The results may provide the basis for promoting the release of varietal aroma and improving wine sensory quality in the wine industry.
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Affiliation(s)
- Tongtong Fan
- College of Enology, Northwest A&F University, Yangling, China
| | - Siyu Jing
- College of Enology, Northwest A&F University, Yangling, China
| | - Hongyan Zhang
- College of Plant Protection, Northwest A&F University, Yangling, China
| | - Xiaobing Yang
- College of Enology, Northwest A&F University, Yangling, China
| | - Guojie Jin
- College of Enology, Northwest A&F University, Yangling, China.,Ningxia Helan Mountain's East Foothill Wine Experiment and Demonstration Station of Northwest A&F University, Yongning, China
| | - Yongsheng Tao
- College of Enology, Northwest A&F University, Yangling, China.,Ningxia Helan Mountain's East Foothill Wine Experiment and Demonstration Station of Northwest A&F University, Yongning, China
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7
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Eremin DB, Fokin VV. Dual Electrospray Ionization Enhancement of Proteins Enabled by DMSO Supercharging Reagent. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:203-206. [PMID: 34850625 DOI: 10.1021/jasms.1c00280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Supercharging reagents assist protein ionization by producing higher charge states and increasing signal intensities, thus improving sensitivity. Described here is an approach to employ a dual-spray ionization source with DMSO as a supercharging reagent to expand in-source supercharging. Under denaturing conditions, dual-source supercharging enhances ionization up to an order of magnitude for proteins of various properties and sizes, but the effect is not uniform. Efficient mixing of solutions from two nebulizing plumes was observed, which allowed sufficient transfer of supercharging molecules to a protein. The described method and proposed mechanism require at least 2.5% of DMSO to produce visible enhancement.
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Affiliation(s)
- Dmitry B Eremin
- Bridge Institute, University of Southern California, 1002 Childs Way, Los Angeles, California 90089-3502, United States
- Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, Los Angeles, California 90089-1661, United States
| | - Valery V Fokin
- Bridge Institute, University of Southern California, 1002 Childs Way, Los Angeles, California 90089-3502, United States
- Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, Los Angeles, California 90089-1661, United States
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8
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Campuzano IDG, Sandoval W. Denaturing and Native Mass Spectrometric Analytics for Biotherapeutic Drug Discovery Research: Historical, Current, and Future Personal Perspectives. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:1861-1885. [PMID: 33886297 DOI: 10.1021/jasms.1c00036] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Mass spectrometry (MS) plays a key role throughout all stages of drug development and is now as ubiquitous as other analytical techniques such as surface plasmon resonance, nuclear magnetic resonance, and supercritical fluid chromatography, among others. Herein, we aim to discuss the history of MS, both electrospray and matrix-assisted laser desorption ionization, specifically for the analysis of antibodies, evolving through to denaturing and native-MS analysis of newer biologic moieties such as antibody-drug conjugates, multispecific antibodies, and interfering nucleic acid-based therapies. We discuss challenging therapeutic target characterization such as membrane protein receptors. Importantly, we compare and contrast the MS and hyphenated analytical chromatographic methods used to characterize these therapeutic modalities and targets within biopharmaceutical research and highlight the importance of appropriate MS deconvolution software and its essential contribution to project progression. Finally, we describe emerging applications and MS technologies that are still predominantly within either a development or academic stage of use but are poised to have significant impact on future drug development within the biopharmaceutic industry once matured. The views reflected herein are personal and are not meant to be an exhaustive list of all relevant MS performed within biopharmaceutical research but are what we feel have been historically, are currently, and will be in the future the most impactful for the drug development process.
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MESH Headings
- Antibodies, Monoclonal/analysis
- Automation, Laboratory
- Biopharmaceutics/methods
- Chromatography, Liquid
- Drug Discovery/methods
- Drug Industry/history
- History, 20th Century
- History, 21st Century
- Humans
- Immunoconjugates/analysis
- Immunoconjugates/chemistry
- Protein Denaturation
- Protein Processing, Post-Translational
- Proteins/analysis
- Spectrometry, Mass, Electrospray Ionization/history
- Spectrometry, Mass, Electrospray Ionization/instrumentation
- Spectrometry, Mass, Electrospray Ionization/methods
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/history
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/instrumentation
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods
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Affiliation(s)
- Iain D G Campuzano
- Discovery Attribute Sciences, Amgen Research, 1 Amgen Center Drive, Thousand Oaks, California 92130, United States
| | - Wendy Sandoval
- Department of Microchemistry, Proteomics and Lipidomics, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
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9
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Nguyen JM, Smith J, Rzewuski S, Legido-Quigley C, Lauber MA. High sensitivity LC-MS profiling of antibody-drug conjugates with difluoroacetic acid ion pairing. MAbs 2019; 11:1358-1366. [PMID: 31500514 PMCID: PMC6816370 DOI: 10.1080/19420862.2019.1658492] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Reversed-phase liquid chromatography (RPLC) separations of proteins using optical detection generally use trifluoroacetic acid (TFA) because it is a strong, hydrophobic acid and a very effective ion-pairing agent for minimizing chromatographic secondary interactions. Conversely and in order to avoid ion suppression, analyses entailing mass spectrometry (MS) detection is often performed with a weaker ion-pairing modifier, like formic acid (FA), but resolution quality may be reduced. To gain both the chromatographic advantages of TFA and the enhanced MS sensitivity of FA, we explored the use of an alternative acid, difluoroacetic acid (DFA). This acid modifier is less acidic and less hydrophobic than TFA and is believed to advantageously affect the surface tension of electrospray droplets. Thus, it is possible to increase MS sensitivity threefold by replacing TFA with DFA. Moreover, we have observed DFA ion pairing to concomitantly produce higher chromatographic resolution than FA and even TFA. For this reason, we prepared and used MS-quality DFA in place of FA and TFA in separations involving IdeS digested, reduced NIST mAb and a proprietary antibody-drug conjugate (ADC), aiming to increase sensitivity, resolution and protein recovery. The resulting method using DFA was qualified and applied to two other ADCs and gave heightened sensitivity, resolution and protein recovery versus analyses using TFA. This new method, based on a purified, trace metal free DFA, can potentially become a state-of-the-art liquid chromatography-MS technique for the deep characterization of ADCs.
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Affiliation(s)
- Jennifer M Nguyen
- School of Science, University of Copenhagen , Frederiksberg , Denmark.,Chemistry Technology Center, Waters Corporation , Milford , MA , USA
| | - Jacquelynn Smith
- BioTherapeutics Pharmaceuticial Sciencies, Pfizer, Inc ., Chesterfield , MO , USA
| | - Susan Rzewuski
- Chemistry Technology Center, Waters Corporation , Milford , MA , USA
| | | | - Matthew A Lauber
- Chemistry Technology Center, Waters Corporation , Milford , MA , USA
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10
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Campuzano IDG, Robinson JH, Hui JO, Shi SDH, Netirojjanakul C, Nshanian M, Egea PF, Lippens JL, Bagal D, Loo JA, Bern M. Native and Denaturing MS Protein Deconvolution for Biopharma: Monoclonal Antibodies and Antibody-Drug Conjugates to Polydisperse Membrane Proteins and Beyond. Anal Chem 2019; 91:9472-9480. [PMID: 31194911 PMCID: PMC6703902 DOI: 10.1021/acs.analchem.9b00062] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Electrospray ionization mass spectrometry (ESI-MS) is a ubiquitously used analytical method applied across multiple departments in biopharma, ranging from early research discovery to process development. Accurate, efficient, and consistent protein MS spectral deconvolution across multiple instrument and detector platforms (time-of-flight, Orbitrap, Fourier-transform ion cyclotron resonance) is essential. When proteins are ionized during the ESI process, a distribution of consecutive multiply charged ions are observed on the m/z scale, either positive [M + nH]n+ or negative [M - nH]n- depending on the ionization polarity. The manual calculation of the neutral molecular weight (MW) of single proteins measured by ESI-MS is simple; however, algorithmic deconvolution is required for more complex protein mixtures to derive accurate MWs. Multiple deconvolution algorithms have evolved over the past two decades, all of which have their advantages and disadvantages, in terms of speed, user-input parameters (or ideally lack thereof), and whether they perform optimally on proteins analyzed under denatured or native-MS and solution conditions. Herein, we describe the utility of a parsimonious deconvolution algorithm (explaining the observed spectra with a minimum number of masses) to process a wide range of highly diverse biopharma relevant and research grade proteins and complexes (PEG-GCSF; an IgG1k; IgG1- and IgG2-biotin covalent conjugates; the membrane protein complex AqpZ; a highly polydisperse empty MSP1D1 nanodisc and the tetradecameric chaperone protein complex GroEL) analyzed under native-MS, denaturing LC-MS, and positive and negative modes of ionization, using multiple instruments and therefore multiple data formats. The implementation of a comb filter and peak sharpening option is also demonstrated to be highly effective for deconvolution of highly polydisperse and enhanced separation of a low level lysine glycation post-translational modification (+162.1 Da), partially processed heavy chain lysine residues (+128.1 Da), and loss of N-acetylglucosamine (GlcNAc; -203.1 Da).
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Affiliation(s)
- Iain D. G. Campuzano
- Amgen Discovery Research, Discovery Attribute Sciences, One Amgen Center Drive, Thousand Oaks, CA, 91320, USA
| | - John H. Robinson
- Amgen Discovery Research, Discovery Attribute Sciences, One Amgen Center Drive, Thousand Oaks, CA, 91320, USA
| | - John O. Hui
- Amgen Discovery Research, Discovery Attribute Sciences, One Amgen Center Drive, Thousand Oaks, CA, 91320, USA
| | - Stone D.-H. Shi
- Amgen Discovery Research, Discovery Attribute Sciences, One Amgen Center Drive, Thousand Oaks, CA, 91320, USA
| | - Chawita Netirojjanakul
- Amgen Discovery Research, Hybrid Modality Engineering, One Amgen Center Drive, Thousand Oaks, CA, 91320, USA
| | - Michael Nshanian
- University of California-Los Angeles, Dept. Chemistry and Biochemistry, Los Angeles, CA, 90095, USA
| | - Pascal F. Egea
- University of California-Los Angeles, Dept. Biological Chemistry, Los Angeles, CA, USA
| | - Jennifer L. Lippens
- Amgen Discovery Research, Discovery Attribute Sciences, One Amgen Center Drive, Thousand Oaks, CA, 91320, USA
| | - Dhanashri Bagal
- Amgen Discovery Research, Discovery Attribute Sciences, Veterans Ways, South San Francisco, CA, 94080, USA
| | - Joseph A. Loo
- Amgen Discovery Research, Hybrid Modality Engineering, One Amgen Center Drive, Thousand Oaks, CA, 91320, USA
- University of California-Los Angeles, Dept. Biological Chemistry, Los Angeles, CA, USA
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11
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Liu Y, LoCaste CE, Liu W, Poltash ML, Russell DH, Laganowsky A. Selective binding of a toxin and phosphatidylinositides to a mammalian potassium channel. Nat Commun 2019; 10:1352. [PMID: 30902995 PMCID: PMC6430785 DOI: 10.1038/s41467-019-09333-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 03/05/2019] [Indexed: 02/05/2023] Open
Abstract
G-protein-gated inward rectifying potassium channels (GIRKs) require Gβγ subunits and phosphorylated phosphatidylinositides (PIPs) for gating. Although studies have provided insight into these interactions, the mechanism of how these events are modulated by Gβγ and the binding affinity between PIPs and GIRKs remains poorly understood. Here, native ion mobility mass spectrometry is employed to directly monitor small molecule binding events to mouse GIRK2. GIRK2 binds the toxin tertiapin Q and PIPs selectively and with significantly higher affinity than other phospholipids. A mutation in GIRK2 that causes a rotation in the cytoplasmic domain, similarly to Gβγ-binding to the wild-type channel, revealed differences in the selectivity towards PIPs. More specifically, PIP isoforms known to weakly activate GIRKs have decreased binding affinity. Taken together, our results reveal selective small molecule binding and uncover a mechanism by which rotation of the cytoplasmic domain can modulate GIRK•PIP interactions.
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Affiliation(s)
- Yang Liu
- Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX, 77030, USA
| | - Catherine E LoCaste
- Department of Chemistry, Texas A&M University, College Station, TX, 77842, USA
| | - Wen Liu
- Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX, 77030, USA
| | - Michael L Poltash
- Department of Chemistry, Texas A&M University, College Station, TX, 77842, USA
| | - David H Russell
- Department of Chemistry, Texas A&M University, College Station, TX, 77842, USA
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, College Station, TX, 77842, USA.
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