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Noel HR, Keerthi S, Ren X, Winkelman JD, Troutman JM, Palmer LD. Genetic synergy between Acinetobacter baumannii undecaprenyl phosphate biosynthesis and the Mla system impacts cell envelope and antimicrobial resistance. mBio 2024; 15:e0280423. [PMID: 38364179 PMCID: PMC10936186 DOI: 10.1128/mbio.02804-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 01/17/2024] [Indexed: 02/18/2024] Open
Abstract
Acinetobacter baumannii is a Gram-negative bacterial pathogen that poses a major health concern due to increasing multidrug resistance. The Gram-negative cell envelope is a key barrier to antimicrobial entry and includes an inner and outer membrane. The maintenance of lipid asymmetry (Mla) system is the main homeostatic mechanism by which Gram-negative bacteria maintain outer membrane asymmetry. Loss of the Mla system in A. baumannii results in attenuated virulence and increased susceptibility to membrane stressors and some antibiotics. We recently reported two strain variants of the A. baumannii type strain ATCC 17978: 17978VU and 17978UN. Here, ∆mlaF mutants in the two ATCC 17978 strains display different phenotypes for membrane stress resistance, antibiotic resistance, and pathogenicity in a murine pneumonia model. Although allele differences in obgE were previously reported to synergize with ∆mlaF to affect growth and stringent response, obgE alleles do not affect membrane stress resistance. Instead, a single-nucleotide polymorphism (SNP) in the essential gene encoding undecaprenyl pyrophosphate (Und-PP) synthase, uppS, results in decreased enzymatic rate and decrease in total Und-P levels in 17978UN compared to 17978VU. The UppSUN variant synergizes with ∆mlaF to reduce capsule and lipooligosaccharide (LOS) levels, increase susceptibility to membrane stress and antibiotics, and reduce persistence in a mouse lung infection. Und-P is a lipid glycan carrier required for the biosynthesis of A. baumannii capsule, cell wall, and glycoproteins. These findings uncover synergy between Und-P and the Mla system in maintaining the A. baumannii cell envelope and antibiotic resistance.IMPORTANCEAcinetobacter baumannii is a critical threat to global public health due to its multidrug resistance and persistence in hospital settings. Therefore, novel therapeutic approaches are urgently needed. We report that a defective undecaprenyl pyrophosphate synthase (UppS) paired with a perturbed Mla system leads to synthetically sick cells that are more susceptible to clinically relevant antibiotics and show reduced virulence in a lung infection model. These results suggest that targeting UppS or undecaprenyl species and the Mla system may resensitize A. baumannii to antibiotics in combination therapies. This work uncovers a previously unknown synergistic relationship in cellular envelope homeostasis that could be leveraged for use in combination therapy against A. baumannii.
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Affiliation(s)
- Hannah R. Noel
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, USA
| | - Sowmya Keerthi
- Department of Chemistry, University of North Carolina Charlotte, Charlotte, North Carolina, USA
| | - Xiaomei Ren
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, USA
| | | | - Jerry M. Troutman
- Department of Chemistry, University of North Carolina Charlotte, Charlotte, North Carolina, USA
| | - Lauren D. Palmer
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, USA
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Noel HR, Keerthi S, Ren X, Winkelman JD, Troutman JM, Palmer LD. Genetic synergy in Acinetobacter baumannii undecaprenyl biosynthesis and maintenance of lipid asymmetry impacts outer membrane and antimicrobial resistance. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.22.556980. [PMID: 37790371 PMCID: PMC10542541 DOI: 10.1101/2023.09.22.556980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Acinetobacter baumannii is a Gram-negative healthcare-associated pathogen that poses a major health concern due to increasing multidrug resistance. The Gram-negative cell envelope is a key barrier to antimicrobial entry and includes an inner and outer membrane. The outer membrane has an asymmetric composition that is important for structural integrity and barrier to the environment. Therefore, Gram-negative bacteria have mechanisms to uphold this asymmetry such as the maintenance of lipid asymmetry system (Mla), which removes glycerophospholipids from the outer leaflet of the outer membrane and transports them to the inner membrane. Loss of this system in A. baumannii results in attenuated virulence and increased susceptibility to membrane stressors and some antibiotics. We recently reported two strain variants of the A. baumannii type strain ATCC 17978, 17978VU and 17978UN. We show here that ΔmlaF mutants in the two strains display different phenotypes for membrane stress resistance, antibiotic resistance, and pathogenicity in a murine pneumonia model. We used comparative genetics to identify interactions between ATCC 17978 strain alleles and mlaF to uncover the cause behind the phenotypic differences. Although allele differences in obgE were previously reported to synergize with ΔmlaF to affect growth and stringent response, we show that obgE alleles do not affect membrane stress resistance. Instead, a single nucleotide polymorphism (SNP) in the essential gene encoding undecaprenyl pyrophosphate (Und-PP) synthase, uppS, synergizes with ΔmlaF to increase susceptibility to membrane stress and antibiotics, and reduce persistence in a mouse lung infection. Und-P is a lipid glycan carrier known to be required for biosynthesis of A. baumannii capsule, cell wall, and glycoproteins. Our data suggest that in the absence of the Mla system, the cellular level of Und-P is critical for envelope integrity, antibiotic resistance, and lipooligosaccharide abundance. These findings uncover synergy between Und-P and the Mla system in maintaining the A. baumannii outer membrane and stress resistance.
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Affiliation(s)
- Hannah R. Noel
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, IL, USA
| | - Sowmya Keerthi
- Department of Chemistry, University of North Carolina Charlotte, Charlotte, NC, USA
| | - Xiaomei Ren
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, IL, USA
| | | | - Jerry M. Troutman
- Department of Chemistry, University of North Carolina Charlotte, Charlotte, NC, USA
| | - Lauren D. Palmer
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, IL, USA
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Nongpiur CGL, Tripathi DK, Poluri KM, Rawat H, Kollipara MR. Ruthenium, rhodium and iridium complexes containing diazafluorene derivative ligands: synthesis and biological studies. J CHEM SCI 2022. [DOI: 10.1007/s12039-021-02004-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Nongpiur CGL, Ghate MM, Tripathi DK, Poluri KM, Kaminsky W, Kollipara MR. Study of versatile coordination modes, antibacterial and radical scavenging activities of arene ruthenium, rhodium and iridium complexes containing fluorenone based thiosemicarbazones. J Organomet Chem 2022. [DOI: 10.1016/j.jorganchem.2021.122148] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Reid AJ, Scarbrough BA, Williams TC, Gates CE, Eade CR, Troutman JM. General Utilization of Fluorescent Polyisoprenoids with Sugar Selective Phosphoglycosyltransferases. Biochemistry 2020; 59:615-626. [PMID: 31876413 DOI: 10.1021/acs.biochem.9b01026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The protective surfaces of bacteria are comprised of polysaccharides and are involved in host invasion and colonization, host immune system evasion, and antibacterial resistance. A major barrier to our fundamental understanding of these complex surface polysaccharides lies in the tremendous diversity in glycan composition among bacterial species. The polyisoprenoid bactoprenyl phosphate (or undecaprenyl phosphate) is an essential lipid carrier necessary for early stages of glycopolymer assembly. Because of the ubiquity of bactoprenyl phosphate in these critical processes, molecular probes appended to this lipid carrier simplify identification of enzymatic roles during polysaccharide bioassembly. A limited number of these probes exist in the literature or have been assessed with such pathways, and the limits of their use are not currently known. Herein, we devise an efficient method for producing fluorescently modified bactoprenyl probes. We further expand our previous efforts utilizing 2-nitrileaniline and additionally prepare nitrobenzoxadizol-tagged bactoprenyl phosphate for the first time. We then assess the enzyme promiscuity of these two probes utilizing four well-characterized initiating phosphoglycosyltransferases: CPS2E (Streptococcus pneumoniae), WbaP (Salmonella enterica), WecA (Escherichia coli), and WecP (Aeromonas hydrophilia). Both probes serve as substrates for these enzymes and could be readily used to investigate a wide range of bacterial glycoassembly pathways. Interestingly, we have also identified unique solubility requirements for the nitrobenzoxadizol moiety for efficient enzymatic utilization that was not observed for the 2-nitrileaniline.
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Cochrane RVK, Alexander FM, Boland C, Fetics SK, Caffrey M, Cochrane SA. From plant to probe: semi-synthesis of labelled undecaprenol analogues allows rapid access to probes for antibiotic targets. Chem Commun (Camb) 2020; 56:8603-8606. [DOI: 10.1039/d0cc03388j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Extraction of undecaprenol from bay leaves followed by synthetic modification is a convenient method to obtain novel chemical probes.
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Affiliation(s)
| | | | - Coilín Boland
- School of Medicine and School of Biochemistry and Immunology
- Trinity Biomedical Sciences Institute
- Trinity College Dublin
- Dublin 2
- Ireland
| | - Susan K. Fetics
- School of Medicine and School of Biochemistry and Immunology
- Trinity Biomedical Sciences Institute
- Trinity College Dublin
- Dublin 2
- Ireland
| | - Martin Caffrey
- School of Medicine and School of Biochemistry and Immunology
- Trinity Biomedical Sciences Institute
- Trinity College Dublin
- Dublin 2
- Ireland
| | - Stephen A. Cochrane
- School of Chemistry and Chemical Engineering
- Queen's University Belfast
- Belfast
- UK
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Dinda S, Sultana T, Sultana S, Patra SC, Mitra AK, Roy S, Pramanik K, Ganguly S. Ruthenocycles of benzothiazolyl and pyridyl hydrazones with ancillary PAHs: synthesis, structure, electrochemistry and antimicrobial activity. NEW J CHEM 2020. [DOI: 10.1039/d0nj01447h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The antimicrobial activity of ruthenocycles of pyridyl and benzothiazolyl hydrazones has been investigated. The study established that such activity is comparatively higher for the complex containing benzothiazolyl hydrazone.
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Affiliation(s)
- Soumitra Dinda
- Department of Chemistry
- St. Xavier's College (Autonomous)
- Kolkata – 700016
- India
| | - Tamanna Sultana
- Department of Microbiology
- St. Xavier's College (Autonomous)
- Kolkata – 700016
- India
| | - Suhana Sultana
- Department of Microbiology
- St. Xavier's College (Autonomous)
- Kolkata – 700016
- India
| | | | - Arup Kumar Mitra
- Department of Microbiology
- St. Xavier's College (Autonomous)
- Kolkata – 700016
- India
| | - Subhadip Roy
- Department of Chemistry
- The ICFAI University Tripura
- India
| | | | - Sanjib Ganguly
- Department of Chemistry
- St. Xavier's College (Autonomous)
- Kolkata – 700016
- India
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Lapasam A, Dkhar L, Joshi N, Poluri KM, Kollipara MR. Antimicrobial selectivity of ruthenium, rhodium, and iridium half sandwich complexes containing phenyl hydrazone Schiff base ligands towards B. thuringiensis and P. aeruginosa bacteria. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2018.09.067] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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9
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A Defective Undecaprenyl Pyrophosphate Synthase Induces Growth and Morphological Defects That Are Suppressed by Mutations in the Isoprenoid Pathway of Escherichia coli. J Bacteriol 2018; 200:JB.00255-18. [PMID: 29986944 DOI: 10.1128/jb.00255-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/05/2018] [Indexed: 01/10/2023] Open
Abstract
The peptidoglycan exoskeleton shapes bacteria and protects them against osmotic forces, making its synthesis the target of many current antibiotics. Peptidoglycan precursors are attached to a lipid carrier and flipped from the cytoplasm into the periplasm to be incorporated into the cell wall. In Escherichia coli, this carrier is undecaprenyl phosphate (Und-P), which is synthesized as a diphosphate by the enzyme undecaprenyl pyrophosphate synthase (UppS). E. coli MG1655 exhibits wild-type morphology at all temperatures, but one of our laboratory strains (CS109) was highly aberrant when grown at 42°C. This strain contained mutations affecting the Und-P synthetic pathway genes uppS, ispH, and idi Normal morphology was restored by overexpressing uppS or by replacing the mutant (uppS31) with the wild-type allele. Importantly, moving uppS31 into MG1655 was lethal even at 30°C, indicating that the altered enzyme was highly deleterious, but growth was restored by adding the CS109 versions of ispH and idi Purified UppSW31R was enzymatically defective at all temperatures, suggesting that it could not supply enough Und-P during rapid growth unless suppressor mutations were present. We conclude that cell wall synthesis is profoundly sensitive to changes in the pool of polyisoprenoids and that isoprenoid homeostasis exerts a particularly strong evolutionary pressure.IMPORTANCE Bacterial morphology is determined primarily by the overall structure of the semirigid macromolecule peptidoglycan. Not only does peptidoglycan contribute to cell shape, but it also protects cells against lysis caused by excess osmotic pressure. Because it is critical for bacterial survival, it is no surprise that many antibiotics target peptidoglycan biosynthesis. However, important gaps remain in our understanding about how this process is affected by peptidoglycan precursor availability. Here, we report that a mutation altering the enzyme that synthesizes Und-P prevents cells from growing at high temperatures and that compensatory mutations in enzymes functioning upstream of uppS can reverse this phenotype. The results highlight the importance of Und-P metabolism for maintaining normal cell wall synthesis and shape.
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Lee M, Hesek D, Zajíček J, Fisher JF, Mobashery S. Synthesis and shift-reagent-assisted full NMR assignment of bacterial (Z 8,E 2,ω)-undecaprenol. Chem Commun (Camb) 2017; 53:12774-12777. [PMID: 29139490 PMCID: PMC5749266 DOI: 10.1039/c7cc06781j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The repeating isoprene unit is a fundamental biosynthetic motif. The repetitive structure presents challenges both for synthesis and for structural characterization. In this synthesis of the (Z8,E2,ω)-undecaprenol of prokaryotic glycobiology, we exemplify solutions to these challenges. Allylation of sulfone-derived carbanions controlled the stereochemistry, and its proof-of-structure was secured by Eu(hfc)3 complexation to disperse the overlaid resonances of its 1H NMR spectrum.
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Affiliation(s)
- Mijoon Lee
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA.
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11
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Sun D, Zhang W, Lv M, Yang E, Zhao Q, Wang W. Antibacterial activity of ruthenium(II) polypyridyl complex manipulated by membrane permeability and cell morphology. Bioorg Med Chem Lett 2015; 25:2068-73. [DOI: 10.1016/j.bmcl.2015.03.090] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Revised: 03/28/2015] [Accepted: 03/30/2015] [Indexed: 11/30/2022]
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12
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Troutman JM, Erickson KM, Scott PM, Hazel JM, Martinez CD, Dodbele S. Tuning the production of variable length, fluorescent polyisoprenoids using surfactant-controlled enzymatic synthesis. Biochemistry 2015; 54:2817-27. [PMID: 25897619 DOI: 10.1021/acs.biochem.5b00310] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bactoprenyl diphosphate (BPP), a two-E eight-Z configuration C55 isoprenoid, serves as a critical anchor for the biosynthesis of complex glycans central to bacterial survival and pathogenesis. BPP is formed by the polymerase undecaprenyl pyrophosphate synthase (UppS), which catalyzes the elongation of a single farnesyl diphosphate (FPP) with eight Z-configuration isoprene units from eight isopentenyl diphosphates. In vitro analysis of UppS and other polyprenyl diphosphate synthases requires the addition of a surfactant such as Triton X-100 to stimulate the release of the hydrophobic product from the enzyme for effective and efficient turnover. Here using a fluorescent 2-nitrileanilinogeranyl diphosphate analogue of FPP, we have found that a wide range of surfactants can stimulate release of product from UppS and that the structure of the surfactant has a major impact on the lengths of products produced by the protein. Of particular importance, shorter chain surfactants promote the release of isoprenoids with four to six Z-configuration isoprene additions, while larger chain surfactants promote the formation of natural isoprenoid lengths (8Z) and larger. We have found that the product chain lengths can be readily controlled and coarsely tuned by adjusting surfactant identity, concentration, and reaction time. We have also found that binary mixtures of just two surfactants can be used to fine-tune isoprenoid lengths. The surfactant effects discovered do not appear to be significantly altered with an alternative isoprenoid substrate. However, the surfactant effects do appear to be dependent on differences in UppS between bacterial species. This work provides new insights into surfactant effects in enzymology and highlights how these effects can be leveraged for the chemoenzymatic synthesis of otherwise difficult to obtain glycan biosynthesis probes. This work also provides key reagents for the systematic analysis of structure-activity relationships between glycan biosynthesis enzymes and isoprenoid structure.
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Affiliation(s)
- Jerry M Troutman
- †Department of Chemistry, ‡Nanoscale Science Program, and §The Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, North Carolina 28223, United States
| | - Katelyn M Erickson
- †Department of Chemistry, ‡Nanoscale Science Program, and §The Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, North Carolina 28223, United States
| | - Phillip M Scott
- †Department of Chemistry, ‡Nanoscale Science Program, and §The Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, North Carolina 28223, United States
| | - Joseph M Hazel
- †Department of Chemistry, ‡Nanoscale Science Program, and §The Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, North Carolina 28223, United States
| | - Christina D Martinez
- †Department of Chemistry, ‡Nanoscale Science Program, and §The Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, North Carolina 28223, United States
| | - Samantha Dodbele
- †Department of Chemistry, ‡Nanoscale Science Program, and §The Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, North Carolina 28223, United States
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Guan Z, Hillrichs K, Ünlü C, Rissanen K, Nieger M, Schmidt A. Synthesis of 2-anilinobenzimidates, anthranilamides, and 2,3-dihydroquinazolin-4(1H)-ones from N-heterocyclic carbenes of indazole. Tetrahedron 2015. [DOI: 10.1016/j.tet.2014.11.054] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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