1
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Keener JE, Goh B, Yoo JS, Oh SF, Brodbelt JS. Top-Down Characterization of Bacterial Lipopolysaccharides and Lipooligosaccharides Using Activated-Electron Photodetachment Mass Spectrometry. Anal Chem 2024; 96:9151-9158. [PMID: 38758019 DOI: 10.1021/acs.analchem.4c00952] [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: 05/18/2024]
Abstract
Lipopolysaccharides (LPS) and lipooligosaccharides (LOS) are located in the outer membrane of Gram-negative bacteria and are comprised of three distinctive parts: lipid A, core oligosaccharide (OS), and O-antigen. The structure of each region influences bacterial stability, toxicity, and pathogenesis. Here, we highlight the use of targeted activated-electron photodetachment (a-EPD) tandem mass spectrometry to characterize LPS and LOS from two crucial players in the human gut microbiota, Escherichia coli Nissle and Bacteroides fragilis. a-EPD is a hybrid activation method that uses ultraviolet photoirradiation to generate charge-reduced radical ions followed by collisional activation to produce informative fragmentation patterns. We benchmark the a-EPD method for top-down characterization of triacyl LOS from E. coli R2, then focus on characterization of LPS from E. coli Nissle and B. fragilis. Notably, a-EPD affords extensive fragmentation throughout the backbone of the core OS and O-antigen regions of LPS from E. coli Nissle. This hybrid approach facilitated the elucidation of structural details for LPS from B. fragilis, revealing a putative hexuronic acid (HexA) conjugated to lipid A.
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Affiliation(s)
- James E Keener
- Department of Chemistry, University of Texas, Austin, Texas 78712, United States
| | - Byoungsook Goh
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, United States
| | - Ji-Sun Yoo
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, United States
| | - Sungwhan F Oh
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, United States
- Program in Immunology, Division of Medical Sciences, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas, Austin, Texas 78712, United States
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2
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Dardelle F, Phelip C, Darabi M, Kondakova T, Warnet X, Combret E, Juranville E, Novikov A, Kerzerho J, Caroff M. Diversity, Complexity, and Specificity of Bacterial Lipopolysaccharide (LPS) Structures Impacting Their Detection and Quantification. Int J Mol Sci 2024; 25:3927. [PMID: 38612737 PMCID: PMC11011966 DOI: 10.3390/ijms25073927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 03/21/2024] [Accepted: 03/23/2024] [Indexed: 04/14/2024] Open
Abstract
Endotoxins are toxic lipopolysaccharides (LPSs), extending from the outer membrane of Gram-negative bacteria and notorious for their toxicity and deleterious effects. The comparison of different LPSs, isolated from various Gram-negative bacteria, shows a global similar architecture corresponding to a glycolipid lipid A moiety, a core oligosaccharide, and outermost long O-chain polysaccharides with molecular weights from 2 to 20 kDa. LPSs display high diversity and specificity among genera and species, and each bacterium contains a unique set of LPS structures, constituting its protective external barrier. Some LPSs are not toxic due to their particular structures. Different, well-characterized, and highly purified LPSs were used in this work to determine endotoxin detection rules and identify their impact on the host. Endotoxin detection is a major task to ensure the safety of human health, especially in the pharma and food sectors. Here, we describe the impact of different LPS structures obtained under different bacterial growth conditions on selective LPS detection methods such as LAL, HEK-blue TLR-4, LC-MS2, and MALDI-MS. In these various assays, LPSs were shown to respond differently, mainly attributable to their lipid A structures, their fatty acid numbers and chain lengths, the presence of phosphate groups, and their possible substitutions.
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Affiliation(s)
- Flavien Dardelle
- LPS-BioSciences, Bâtiment 440, Université de Paris-Saclay, 91400 Orsay, France; (F.D.); (M.D.); (E.J.)
| | - Capucine Phelip
- HEPHAISTOS-Pharma, Bâtiment 440, Université de Paris-Saclay, 91400 Orsay, France; (C.P.); (A.N.); (J.K.)
| | - Maryam Darabi
- LPS-BioSciences, Bâtiment 440, Université de Paris-Saclay, 91400 Orsay, France; (F.D.); (M.D.); (E.J.)
| | - Tatiana Kondakova
- LPS-BioSciences, Bâtiment 440, Université de Paris-Saclay, 91400 Orsay, France; (F.D.); (M.D.); (E.J.)
| | - Xavier Warnet
- LPS-BioSciences, Bâtiment 440, Université de Paris-Saclay, 91400 Orsay, France; (F.D.); (M.D.); (E.J.)
| | - Edyta Combret
- LPS-BioSciences, Bâtiment 440, Université de Paris-Saclay, 91400 Orsay, France; (F.D.); (M.D.); (E.J.)
| | - Eugenie Juranville
- LPS-BioSciences, Bâtiment 440, Université de Paris-Saclay, 91400 Orsay, France; (F.D.); (M.D.); (E.J.)
| | - Alexey Novikov
- HEPHAISTOS-Pharma, Bâtiment 440, Université de Paris-Saclay, 91400 Orsay, France; (C.P.); (A.N.); (J.K.)
| | - Jerome Kerzerho
- HEPHAISTOS-Pharma, Bâtiment 440, Université de Paris-Saclay, 91400 Orsay, France; (C.P.); (A.N.); (J.K.)
| | - Martine Caroff
- LPS-BioSciences, Bâtiment 440, Université de Paris-Saclay, 91400 Orsay, France; (F.D.); (M.D.); (E.J.)
- HEPHAISTOS-Pharma, Bâtiment 440, Université de Paris-Saclay, 91400 Orsay, France; (C.P.); (A.N.); (J.K.)
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3
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Guan XL, Loh JYX, Lizwan M, Chan SCM, Kwan JMC, Lim TP, Koh TH, Hsu LY, Lee BTK. LipidA-IDER to Explore the Global Lipid A Repertoire of Drug-Resistant Gram-Negative Bacteria. Anal Chem 2023; 95:602-611. [PMID: 36599414 PMCID: PMC9850412 DOI: 10.1021/acs.analchem.1c03566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
With the global emergence of drug-resistant bacteria causing difficult-to-treat infections, there is an urgent need for a tool to facilitate studies on key virulence and antimicrobial resistant factors. Mass spectrometry (MS) has contributed substantially to the elucidation of the structure-function relationships of lipid A, the endotoxic component of lipopolysaccharide which also serves as an important protective barrier against antimicrobials. Here, we present LipidA-IDER, an automated structure annotation tool for system-level scale identification of lipid A from high-resolution tandem mass spectrometry (MS2) data. LipidA-IDER was validated against previously reported structures of lipid A in the reference bacteria, Escherichia coli and Pseudomonas aeruginosa. Using MS2 data of variable quality, we demonstrated LipidA-IDER annotated lipid A with a performance of 71.2% specificity and 70.9% sensitivity, offering greater accuracy than existing lipidomics software. The organism-independent workflow was further applied to a panel of six bacterial species: E. coli and Gram-negative members of ESKAPE pathogens. A comprehensive atlas comprising 188 distinct lipid A species, including remodeling intermediates, was generated and can be integrated with software including MS-DIAL and Metabokit for identification and semiquantitation. Systematic comparison of a pair of polymyxin-sensitive and polymyxin-resistant Acinetobacter baumannii isolated from a human patient unraveled multiple key lipid A structural features of polymyxin resistance within a single analysis. Probing the lipid A landscape of bacteria using LipidA-IDER thus holds immense potential for advancing our understanding of the vast diversity and structural complexity of a key lipid virulence and antimicrobial-resistant factor. LipidA-IDER is freely available at https://github.com/Systems-Biology-Of-Lipid-Metabolism-Lab/LipidA-IDER.
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Affiliation(s)
- Xue Li Guan
- Lee
Kong Chian School of Medicine, Nanyang Technological
University, Singapore 636921, Singapore,. Tel: +65 6592 3957
| | - Johnathan Yi-Xiong Loh
- Lee
Kong Chian School of Medicine, Nanyang Technological
University, Singapore 636921, Singapore
| | - Marco Lizwan
- Lee
Kong Chian School of Medicine, Nanyang Technological
University, Singapore 636921, Singapore
| | - Sharon Cui Mun Chan
- Lee
Kong Chian School of Medicine, Nanyang Technological
University, Singapore 636921, Singapore
| | - Jeric Mun Chung Kwan
- Lee
Kong Chian School of Medicine, Nanyang Technological
University, Singapore 636921, Singapore
| | - Tze Peng Lim
- Department
of Pharmacy, Singapore General Hospital, Singapore 169608, Singapore
| | - Tse Hsien Koh
- Department
of Microbiology, Singapore General Hospital, Singapore 169608, Singapore
| | - Li-Yang Hsu
- Saw Swee
Hock School of Public Health, National University
of Singapore, Singapore 117549, Singapore
| | - Bernett Teck Kwong Lee
- Lee
Kong Chian School of Medicine, Nanyang Technological
University, Singapore 636921, Singapore,Centre
for Biomedical Informatics, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore,Singapore
Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore 138648, Singapore
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Yang H, Smith RD, Chandler CE, Johnson JK, Jackson SN, Woods AS, Scott AJ, Goodlett DR, Ernst RK. Lipid A Structural Determination from a Single Colony. Anal Chem 2022; 94:7460-7465. [PMID: 35576511 PMCID: PMC9392460 DOI: 10.1021/acs.analchem.1c05394] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We describe an innovative use for the recently reported fast lipid analysis technique (FLAT) that allows for the generation of MALDI tandem mass spectrometry data suitable for lipid A structure analysis directly from a single Gram-negative bacterial colony. We refer to this tandem MS version of FLAT as FLATn. Neither technique requires sophisticated sample preparation beyond the selection of a single bacterial colony, which significantly reduces overall analysis time (∼1 h), as compared to conventional methods. Moreover, the tandem mass spectra generated by FLATn provides comprehensive information on fragments of lipid A, for example, ester bonded acyl chain dissociations, cross-ring cleavages, and glycosidic bond dissociations, all of which allow the facile determination of novel lipid A structures or confirmation of expected structures. In addition to generating tandem mass spectra directly from single colonies, we also show that FLATn can be used to analyze lipid A structures taken directly from a complex biological clinical sample without the need for ex vivo growth. From a urine sample from a patient with an E. coli infection, FLATn identified the organism and demonstrated that this clinical isolate carried the mobile colistin resistance-1 gene (mcr-1) that results in the addition of a phosphoethanolamine moiety and subsequently resistance to the antimicrobial, colistin (polymyxin E). Moreover, FLATn allowed for the determination of the existence of a structural isomer in E. coli lipid A that had either a 1- or 4'-phosphate group modification by phosphoethanolamine generated by a change of bacterial culture conditions.
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Affiliation(s)
- Hyojik Yang
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201 USA
| | - Richard D. Smith
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201 USA
- Department of Pathology, School of Medicine, University of Maryland, Baltimore, MD 21201 USA
| | - Courtney E. Chandler
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201 USA
| | - J. Kristie Johnson
- Department of Pathology, School of Medicine, University of Maryland, Baltimore, MD 21201 USA
| | - Shelley N. Jackson
- Translational Analytical Core, NIDA IRP, NIH, Biomedical Research Center, 251 Bayview Boulevard, Suite 200, Room 01B216, Baltimore, MD 21224, USA
| | - Amina S. Woods
- Structural Biology Core, NIDA IRP, NIH, 333 Cassell Drive, Room 1120, Baltimore, MD 21224, USA
- Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine. Baltimore, MD 21205 USA
| | - Alison J. Scott
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201 USA
- Maastricht MultiModal Molecular Imaging (M4I) Institute, Maastricht University, Maastricht 6229 ER, Netherlands
| | - David R. Goodlett
- Department of Biochemistry and Microbiology, University of Victoria, 3800 Finnerty Road. Victoria, BC V8P 5C2, Canada
- International Centre for Cancer Vaccine Science, University of Gdańsk, ul. Kładki 24 80-822 Gdańsk, Poland
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201 USA
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5
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Snyder DT, Harvey SR, Wysocki VH. Surface-induced Dissociation Mass Spectrometry as a Structural Biology Tool. Chem Rev 2022; 122:7442-7487. [PMID: 34726898 PMCID: PMC9282826 DOI: 10.1021/acs.chemrev.1c00309] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Native mass spectrometry (nMS) is evolving into a workhorse for structural biology. The plethora of online and offline preparation, separation, and purification methods as well as numerous ionization techniques combined with powerful new hybrid ion mobility and mass spectrometry systems has illustrated the great potential of nMS for structural biology. Fundamental to the progression of nMS has been the development of novel activation methods for dissociating proteins and protein complexes to deduce primary, secondary, tertiary, and quaternary structure through the combined use of multiple MS/MS technologies. This review highlights the key features and advantages of surface collisions (surface-induced dissociation, SID) for probing the connectivity of subunits within protein and nucleoprotein complexes and, in particular, for solving protein structure in conjunction with complementary techniques such as cryo-EM and computational modeling. Several case studies highlight the significant role SID, and more generally nMS, will play in structural elucidation of biological assemblies in the future as the technology becomes more widely adopted. Cases are presented where SID agrees with solved crystal or cryoEM structures or provides connectivity maps that are otherwise inaccessible by "gold standard" structural biology techniques.
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Affiliation(s)
- Dalton T. Snyder
- Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, OH 43210
| | - Sophie R. Harvey
- Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, OH 43210
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
| | - Vicki H. Wysocki
- Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, OH 43210
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
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6
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Snyder DT, Lin YF, Somogyi A, Wysocki V. Tandem surface-induced dissociation of protein complexes on an ultrahigh resolution platform. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2021; 461:116503. [PMID: 33889055 PMCID: PMC8057730 DOI: 10.1016/j.ijms.2020.116503] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We describe instrumentation for conducting tandem surface-induced dissociation (tSID) of native protein complexes on an ultrahigh resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. The two stages of SID are accomplished with split lenses replacing the entrance lenses of the quadrupole mass filter (stage 1, referred to herein as SID-Q) and the collision cell (stage 2, Q-SID). After SID-Q, the scattered projectile ions and subcomplexes formed in transit traverse the 20 mm pre-filter prior to the mass-selecting quadrupole, providing preliminary insights into the SID fragmentation kinetics of noncovalent protein complexes. The isolated SID fragments (subcomplexes) are then fragmented by SID in the collision cell entrance lens (Q-SID), generating subcomplexes of subcomplexes. We show that the ultrahigh resolution of the FT-ICR can be used for deconvolving species overlapping in m/z, which are particularly prominent in tandem SID spectra due to the combination of symmetric charge partitioning and narrow product ion charge state distributions. Various protein complex topologies are explored, including homotetramers, homopentamers, a homohexamer, and a heterohexamer.
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Affiliation(s)
- Dalton T. Snyder
- Resource for Native MS Guided Structural Biology, The Ohio State University, Columbus OH, USA 43210
| | - Yu-Fu Lin
- Resource for Native MS Guided Structural Biology, The Ohio State University, Columbus OH, USA 43210
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus OH, USA 43210
| | - Arpad Somogyi
- Resource for Native MS Guided Structural Biology, The Ohio State University, Columbus OH, USA 43210
| | - Vicki Wysocki
- Resource for Native MS Guided Structural Biology, The Ohio State University, Columbus OH, USA 43210
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus OH, USA 43210
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7
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Brodbelt JS, Morrison LJ, Santos I. Ultraviolet Photodissociation Mass Spectrometry for Analysis of Biological Molecules. Chem Rev 2020; 120:3328-3380. [PMID: 31851501 PMCID: PMC7145764 DOI: 10.1021/acs.chemrev.9b00440] [Citation(s) in RCA: 139] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The development of new ion-activation/dissociation methods continues to be one of the most active areas of mass spectrometry owing to the broad applications of tandem mass spectrometry in the identification and structural characterization of molecules. This Review will showcase the impact of ultraviolet photodissociation (UVPD) as a frontier strategy for generating informative fragmentation patterns of ions, especially for biological molecules whose complicated structures, subtle modifications, and large sizes often impede molecular characterization. UVPD energizes ions via absorption of high-energy photons, which allows access to new dissociation pathways relative to more conventional ion-activation methods. Applications of UVPD for the analysis of peptides, proteins, lipids, and other classes of biologically relevant molecules are emphasized in this Review.
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Affiliation(s)
- Jennifer S. Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Lindsay J. Morrison
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Inês Santos
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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8
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A Whole-Cell Screen Identifies Small Bioactives That Synergize with Polymyxin and Exhibit Antimicrobial Activities against Multidrug-Resistant Bacteria. Antimicrob Agents Chemother 2020; 64:AAC.01677-19. [PMID: 31844003 DOI: 10.1128/aac.01677-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 12/05/2019] [Indexed: 12/19/2022] Open
Abstract
The threat of diminished antibiotic discovery has global health care in crisis. In the United States, it is estimated each year that over 2 million bacterial infections are resistant to first-line antibiotic treatments and cost in excess of 20 billion dollars. Many of these cases result from infection with the ESKAPE pathogens ( Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species), which are multidrug-resistant bacteria that often cause community- and hospital-acquired infections in both healthy and immunocompromised patients. Physicians have turned to last-resort antibiotics like polymyxins to tackle these pathogens, and as a consequence, polymyxin resistance has emerged and is spreading. Barring the discovery of new antibiotics, another route to successfully mitigate polymyxin resistance is to identify compounds that can complement the existing arsenal of antibiotics. We recently designed and performed a large-scale robotic screen to identify 43 bioactive compounds that act synergistically with polymyxin B to inhibit the growth of polymyxin-resistant Escherichia coli Of these 43 compounds, 5 lead compounds were identified and characterized using various Gram-negative bacterial organisms to better assess their synergistic activity with polymyxin. Several of these compounds reduce polymyxin to an MIC of <2 μg/ml against polymyxin-resistant and polymyxin-heteroresistant Gram-negative pathogens. Likewise, four of these compounds exhibit antimicrobial activity against Gram-positive bacteria, one of which rapidly eradicated methicillin-resistant Staphylococcus aureus We present multiple first-generation (i.e., not yet optimized) compounds that warrant further investigation and optimization, since they can act both synergistically with polymyxin and also as lone antimicrobials for combating ESKAPE pathogens.
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9
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Olagnon C, Monjaras Feria J, Grünwald‐Gruber C, Blaukopf M, Valvano MA, Kosma P. Synthetic Phosphodiester-Linked 4-Amino-4-deoxy-l-arabinose Derivatives Demonstrate that ArnT is an Inverting Aminoarabinosyl Transferase. Chembiochem 2019; 20:2936-2948. [PMID: 31233657 PMCID: PMC6902282 DOI: 10.1002/cbic.201900349] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Indexed: 12/22/2022]
Abstract
4-Amino-4-deoxy-l-arabinopyranose (Ara4N) residues have been linked to antibiotic resistance due to reduction of the negative charge in the lipid A and core regions of the bacterial lipopolysaccharide (LPS). To study the enzymatic transfer of Ara4N onto lipid A, which is catalysed by the ArnT transferase, we chemically synthesised a series of anomeric phosphodiester-linked lipid Ara4N derivatives containing linear aliphatic chains as well as E- and Z-configured monoterpene units. Coupling reactions were based on sugar-derived H-phosphonates, followed by oxidation and global deprotection. The enzymatic Ara4N transfer was performed in vitro with crude membranes from a deep-rough mutant from Escherichia coli as acceptor. Product formation was detected by TLC and LC-ESI-QTOF mass spectrometry. Out of seven analogues tested, only the α-neryl derivative was accepted by the Burkholderia cenocepacia ArnT protein, leading to substitution of the Kdo2 -lipid A acceptor and thus affording evidence that ArnT is an inverting glycosyl transferase that requires the Z-configured double bond next to the anomeric phosphate moiety. This approach provides an easily accessible donor substrate for biochemical studies relating to modifications of bacterial LPS that modulate antibiotic resistance and immune recognition.
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Affiliation(s)
- Charlotte Olagnon
- Department of ChemistryUniversity of Natural Resources and Life Sciences–ViennaMuthgasse 181190ViennaAustria
| | - Julia Monjaras Feria
- Wellcome-Wolfson Institute of Experimental MedicineQueen's University Belfast97 Lisburn RoadBT9 7BLBelfastUK
| | - Clemens Grünwald‐Gruber
- Department of ChemistryUniversity of Natural Resources and Life Sciences–ViennaMuthgasse 181190ViennaAustria
| | - Markus Blaukopf
- Department of ChemistryUniversity of Natural Resources and Life Sciences–ViennaMuthgasse 181190ViennaAustria
| | - Miguel A. Valvano
- Wellcome-Wolfson Institute of Experimental MedicineQueen's University Belfast97 Lisburn RoadBT9 7BLBelfastUK
| | - Paul Kosma
- Department of ChemistryUniversity of Natural Resources and Life Sciences–ViennaMuthgasse 181190ViennaAustria
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10
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Macias LA, Feider CL, Eberlin LS, Brodbelt JS. Hybrid 193 nm Ultraviolet Photodissociation Mass Spectrometry Localizes Cardiolipin Unsaturations. Anal Chem 2019; 91:12509-12516. [PMID: 31490676 DOI: 10.1021/acs.analchem.9b03278] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Developing alternative MS/MS strategies to distinguish isomeric lipids has become a high impact goal in shotgun lipidomics. Novel approaches have been developed to resolve structural features that are not discernible by traditional shotgun methods and have consequently promoted the discovery of new disease biomarkers. However, these methods have largely been limited to characterizing lipids with low structural complexity. Here, ultraviolet photodissociation (UVPD) strategies for phospholipid characterization are expanded for analysis of cardiolipins (CL), a class of phospholipids that exhibits a higher degree of structural complexity. A hybrid collision induced dissociation/193 nm UVPD (CID/UVPD) approach was implemented to pinpoint the location of both double bond and cyclopropyl unsaturations on the four acyl chains of CLs. This strategy was complemented with CID for the de novo elucidation of unknown CLs in biological extracts.
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Affiliation(s)
- Luis A Macias
- Department of Chemistry , University of Texas , Austin , Texas 78712 , United States
| | - Clara L Feider
- Department of Chemistry , University of Texas , Austin , Texas 78712 , United States
| | - Livia S Eberlin
- Department of Chemistry , University of Texas , Austin , Texas 78712 , United States
| | - Jennifer S Brodbelt
- Department of Chemistry , University of Texas , Austin , Texas 78712 , United States
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11
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Klein DR, Powers MJ, Trent MS, Brodbelt JS. Top-Down Characterization of Lipooligosaccharides from Antibiotic-Resistant Bacteria. Anal Chem 2019; 91:9608-9615. [PMID: 31305072 PMCID: PMC6702669 DOI: 10.1021/acs.analchem.9b00940] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Modification of structures of lipooligosaccharides (LOS) represents one prevalent mechanism by which Gram-negative bacteria can become resistant to key antibiotics. Owing to the significant complexity of LOS, the structural characterization of these amphipathic lipids has largely focused on elucidation of the lipid A substructures. Analysis of intact LOS enables detection of core oligosaccharide modifications and gives insight into the heterogeneity that results from combinations of lipid A and oligosaccharide substructures. Top-down analysis of intact LOS also provides the opportunity to determine unknown oligosaccharide structures, which is particularly advantageous in the context of glycoconjugate vaccine development. Advances in mass spectrometry technologies, including the development of MSn capabilities and alternative ion activation techniques, have made top-down analysis an indispensable tool for structural characterization of complex biomolecules. Here we combine online chromatographic separations with MS3 utilizing ultraviolet photodissociation (UVPD) and higher-energy collisional dissociation (HCD). HCD generally provides information about the presence of labile modifications via neutral loss fragments in addition to the saccharide linkage arrangement, whereas UVPD gives more detailed insight about saccharide branching and the positions of nonstoichiometric modifications. This integrated approach was used to characterize LOS from Acinetobacter baumannii 1205 and 5075. Notably, MS3 analysis of A. baumannii 1205, an antibiotic-resistant strain, confirmed phosphoethanolamine and hexosamine modification of the lipid A substructure and further enabled derivation of a core oligosaccharide structure.
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Affiliation(s)
- Dustin R. Klein
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712
| | - Matthew J. Powers
- Department of Infectious Diseases, The University of Georgia, College of Veterinary Medicine, Athens, GA 30602
- Department of Microbiology, The University of Georgia, College of Arts and Sciences, Athens, GA 30602
| | - M. Stephen Trent
- Department of Infectious Diseases, The University of Georgia, College of Veterinary Medicine, Athens, GA 30602
- Department of Microbiology, The University of Georgia, College of Arts and Sciences, Athens, GA 30602
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12
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Crittenden CM, Escobar EE, Williams PE, Sanders JD, Brodbelt JS. Characterization of Antigenic Oligosaccharides from Gram-Negative Bacteria via Activated Electron Photodetachment Mass Spectrometry. Anal Chem 2019; 91:4672-4679. [PMID: 30844257 DOI: 10.1021/acs.analchem.9b00048] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Lipooligosaccharides (LOS), composed of hydrophilic oligosaccharides and hydrophobic lipid A domains, are found on the outer membranes of Gram-negative bacteria. Here we report the characterization of deacylated LOS of LPS by activated-electron photodetachment mass spectrometry. Collision induced dissociation (CID) of these phosphorylated oligosaccharides produces simple MS/MS spectra with most fragment ions arising from cleavages near the reducing end of the molecule where the phosphate groups are located. In contrast, 193 nm ultraviolet photodissociation (UVPD) generates a wide array of product ions throughout the oligosaccharide including cross-ring fragments that illuminate the branching patterns. However, there are also product ions that are redundant or uninformative, resulting in more congested spectra that complicate interpretation. In this work, a hybrid UVPD-CID approach known as activated-electron photodetachment (a-EPD) affords less congested spectra than UVPD alone and richer fragmentation patterns than CID alone. a-EPD combines UVPD of negatively charged oligosaccharides to yield abundant charge-reduced radical ions which are subsequently interrogated by collisional activation. CID of the charge-reduced precursors results in extensive fragmentation throughout the backbone of the oligosaccharide. This hybridized a-EPD approach was employed to characterize the structure and branching pattern of deacylated LOS of E. coli.
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Affiliation(s)
| | - Edwin E Escobar
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Peggy E Williams
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
| | - James D Sanders
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Jennifer S Brodbelt
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
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