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Benjamin KN, Goyal A, Nair RV, Endy D. Genome-wide transcription response of Staphylococcus epidermidis to heat shock and medically relevant glucose levels. Front Microbiol 2024; 15:1408796. [PMID: 39104585 PMCID: PMC11298487 DOI: 10.3389/fmicb.2024.1408796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 06/24/2024] [Indexed: 08/07/2024] Open
Abstract
Skin serves as both barrier and interface between body and environment. Skin microbes are intermediaries evolved to respond, transduce, or act in response to changing environmental or physiological conditions. We quantified genome-wide changes in gene expression levels for one abundant skin commensal, Staphylococcus epidermidis, in response to an internal physiological signal, glucose levels, and an external environmental signal, temperature. We found 85 of 2,354 genes change up to ~34-fold in response to medically relevant changes in glucose concentration (0-17 mM; adj p ≤0.05). We observed carbon catabolite repression in response to a range of glucose spikes, as well as upregulation of genes involved in glucose utilization in response to persistent glucose. We observed 366 differentially expressed genes in response to a physiologically relevant change in temperature (37-45°C; adj p ≤ 0.05) and an S. epidermidis heat-shock response that mostly resembles the heat-shock response of related staphylococcal species. DNA motif analysis revealed CtsR and CIRCE operator sequences arranged in tandem upstream of dnaK and groESL operons. We identified and curated 38 glucose-responsive genes as candidate ON or OFF switches for use in controlling synthetic genetic systems. Such systems might be used to instrument the in-situ skin microbiome or help control microbes bioengineered to serve as embedded diagnostics, monitoring, or treatment platforms.
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Affiliation(s)
| | - Aditi Goyal
- Biomedical Data Science, Stanford University School of Medicine, Stanford, CA, United States
| | - Ramesh V. Nair
- Stanford Center for Genomics and Personalized Medicine, Stanford University School of Medicine, Stanford, CA, United States
| | - Drew Endy
- Bioengineering, Stanford University, Stanford, CA, United States
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2
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Li FKK, Worrall LJ, Gale RT, Brown ED, Strynadka NCJ. Cryo-EM analysis of S. aureus TarL, a polymerase in wall teichoic acid biogenesis central to virulence and antibiotic resistance. SCIENCE ADVANCES 2024; 10:eadj3864. [PMID: 38416829 PMCID: PMC10901376 DOI: 10.1126/sciadv.adj3864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 01/23/2024] [Indexed: 03/01/2024]
Abstract
Wall teichoic acid (WTA), a covalent adduct of Gram-positive bacterial cell wall peptidoglycan, contributes directly to virulence and antibiotic resistance in pathogenic species. Polymerization of the Staphylococcus aureus WTA ribitol-phosphate chain is catalyzed by TarL, a member of the largely uncharacterized TagF-like family of membrane-associated enzymes. We report the cryo-electron microscopy structure of TarL, showing a tetramer that forms an extensive membrane-binding platform of monotopic helices. TarL is composed of an amino-terminal immunoglobulin-like domain and a carboxyl-terminal glycosyltransferase-B domain for ribitol-phosphate polymerization. The active site of the latter is complexed to donor substrate cytidine diphosphate-ribitol, providing mechanistic insights into the catalyzed phosphotransfer reaction. Furthermore, the active site is surrounded by electropositive residues that serve to retain the lipid-linked acceptor for polymerization. Our data advance general insight into the architecture and membrane association of the still poorly characterized monotopic membrane protein class and present molecular details of ribitol-phosphate polymerization that may aid in the design of new antimicrobials.
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Affiliation(s)
- Franco K K Li
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Blood Research, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Liam J Worrall
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Blood Research, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Robert T Gale
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Eric D Brown
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Natalie C J Strynadka
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Blood Research, The University of British Columbia, Vancouver, British Columbia, Canada
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3
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Yang J, Bowring JZ, Krusche J, Lehmann E, Bejder BS, Silva SF, Bojer MS, Grunert T, Peschel A, Ingmer H. Cross-species communication via agr controls phage susceptibility in Staphylococcus aureus. Cell Rep 2023; 42:113154. [PMID: 37725513 DOI: 10.1016/j.celrep.2023.113154] [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: 04/09/2023] [Revised: 08/06/2023] [Accepted: 09/01/2023] [Indexed: 09/21/2023] Open
Abstract
Bacteria use quorum sensing (QS) to coordinate group behavior in response to cell density, and some bacterial viruses (phages) also respond to QS. In Staphylococcus aureus, the agr-encoded QS system relies on accumulation of auto-inducing cyclic peptides (AIPs). Other staphylococci also produce AIPs of which many inhibit S. aureus agr. We show that agr induction reduces expression of tarM, encoding a glycosyltransferase responsible for α-N-acetylglucosamine modification of the major S. aureus phage receptor, the wall teichoic acids. This allows lytic phage Stab20 and related phages to infect and kill S. aureus. However, in mixed communities, producers of inhibitory AIPs like S. haemolyticus, S. caprae, and S. pseudintermedius inhibit S. aureus agr, thereby impeding phage infection. Our results demonstrate that cross-species interactions dramatically impact phage susceptibility. These interactions likely influence microbial ecology and impact the efficacy of phages in medical and biotechnological applications such as phage therapy.
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Affiliation(s)
- Jingxian Yang
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Copenhagen, Denmark
| | - Janine Zara Bowring
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Copenhagen, Denmark
| | - Janes Krusche
- Department of Infection Biology, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076 Tübingen, Germany; Cluster of Excellence "Controlling Microbes to Fight Infections (CMFI)," German Center for Infection Research (DZIF), Tübingen, Germany
| | - Esther Lehmann
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Copenhagen, Denmark
| | - Benjamin Svejdal Bejder
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Stephanie Fulaz Silva
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Copenhagen, Denmark
| | - Martin Saxtorph Bojer
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Copenhagen, Denmark
| | - Tom Grunert
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, 1210 Vienna, Austria
| | - Andreas Peschel
- Department of Infection Biology, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076 Tübingen, Germany; Cluster of Excellence "Controlling Microbes to Fight Infections (CMFI)," German Center for Infection Research (DZIF), Tübingen, Germany
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Copenhagen, Denmark.
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4
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Yao H, Li G, Xiong X, Jin F, Li S, Xie X, Zhong D, Zhang R, Meng F, Yin Y, Jiao X. LygA retention on the surface of Listeria monocytogenes via its interaction with wall teichoic acid modulates bacterial homeostasis and virulence. PLoS Pathog 2023; 19:e1011482. [PMID: 37379353 DOI: 10.1371/journal.ppat.1011482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 06/13/2023] [Indexed: 06/30/2023] Open
Abstract
Wall teichoic acid (WTA) is the abundant cell wall-associated glycopolymer in Gram-positive bacteria, playing crucial roles in surface proteins retention, bacterial homeostasis, and virulence. Hypervirulent serovar (SV) 4h Listeria monocytogenes is a newly designated serotype with only galactosylated (Gal) type II WTA. Although the surface association of some proteins relies on the WTA glycosylation, the nature and function of the noncovalent interactions between cell wall-associated proteins and WTA are less known. In this study, we found Gal-WTA plays a key role in modulating the novel glycine-tryptophan (GW) domain-containing autolysin protein LygA through direct interactions. An SV 4h strain deficient in WTA galactosylation (XYSNΔgalT) showed a dramatic reduction of LygA on the cell surface, significantly decreasing the autolytic activity, impairing the bacterial colonization in colon and brain. Notably, we demonstrated LygA binds to Gal-WTA with high affinity through the GW domain and that the extent of binding increases with the number of GW domains. Moreover, we confirmed the direct Gal-dependent binding of the GW protein Auto from the type I WTA strain, which has no interaction with l-rhamnosylated WTA, indicating that the complexity of both WTA and GW proteins can affect the coordination patterns. Altogether, our findings suggest that both the glycosylation patterns of WTA and a fixed numbers of GW domains are closely associated with the retention of LygA on the cell surface, which facilitates L. monocytogenes infection by promoting bacteria colonization in intestine and brain.
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Affiliation(s)
- Hao Yao
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA of China, Yangzhou, Jiangsu Province, China
- Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou, Jiangsu Province, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, Jiangsu Province, China
| | - Guo Li
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA of China, Yangzhou, Jiangsu Province, China
- Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou, Jiangsu Province, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, Jiangsu Province, China
| | - Xianglian Xiong
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA of China, Yangzhou, Jiangsu Province, China
- Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou, Jiangsu Province, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, Jiangsu Province, China
| | - Fanxin Jin
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA of China, Yangzhou, Jiangsu Province, China
- Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou, Jiangsu Province, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, Jiangsu Province, China
| | - Sirui Li
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA of China, Yangzhou, Jiangsu Province, China
- Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou, Jiangsu Province, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, Jiangsu Province, China
| | - Xinyu Xie
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA of China, Yangzhou, Jiangsu Province, China
- Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou, Jiangsu Province, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, Jiangsu Province, China
| | - Dan Zhong
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA of China, Yangzhou, Jiangsu Province, China
- Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou, Jiangsu Province, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, Jiangsu Province, China
| | - Renling Zhang
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA of China, Yangzhou, Jiangsu Province, China
- Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou, Jiangsu Province, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, Jiangsu Province, China
| | - Fanzeng Meng
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA of China, Yangzhou, Jiangsu Province, China
- Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou, Jiangsu Province, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, Jiangsu Province, China
| | - Yuelan Yin
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA of China, Yangzhou, Jiangsu Province, China
- Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou, Jiangsu Province, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, Jiangsu Province, China
| | - Xin'an Jiao
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA of China, Yangzhou, Jiangsu Province, China
- Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou, Jiangsu Province, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, Jiangsu Province, China
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5
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Patel H, Rawat S. A genetic regulatory see-saw of biofilm and virulence in MRSA pathogenesis. Front Microbiol 2023; 14:1204428. [PMID: 37434702 PMCID: PMC10332168 DOI: 10.3389/fmicb.2023.1204428] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 05/30/2023] [Indexed: 07/13/2023] Open
Abstract
Staphylococcus aureus is one of the most common opportunistic human pathogens causing several infectious diseases. Ever since the emergence of the first methicillin-resistant Staphylococcus aureus (MRSA) strain decades back, the organism has been a major cause of hospital-acquired infections (HA-MRSA). The spread of this pathogen across the community led to the emergence of a more virulent subtype of the strain, i.e., Community acquired Methicillin resistant Staphylococcus aureus (CA-MRSA). Hence, WHO has declared Staphylococcus aureus as a high-priority pathogen. MRSA pathogenesis is remarkable because of the ability of this "superbug" to form robust biofilm both in vivo and in vitro by the formation of polysaccharide intercellular adhesin (PIA), extracellular DNA (eDNA), wall teichoic acids (WTAs), and capsule (CP), which are major components that impart stability to a biofilm. On the other hand, secretion of a diverse array of virulence factors such as hemolysins, leukotoxins, enterotoxins, and Protein A regulated by agr and sae two-component systems (TCS) aids in combating host immune response. The up- and downregulation of adhesion genes involved in biofilm formation and genes responsible for synthesizing virulence factors during different stages of infection act as a genetic regulatory see-saw in the pathogenesis of MRSA. This review provides insight into the evolution and pathogenesis of MRSA infections with a focus on genetic regulation of biofilm formation and virulence factors secretion.
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Affiliation(s)
| | - Seema Rawat
- Microbiology Laboratory, School of Life Sciences, Central University of Gujarat, Gandhinagar, Gujarat, India
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6
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Lu Y, Chen F, Zhao Q, Cao Q, Chen R, Pan H, Wang Y, Huang H, Huang R, Liu Q, Li M, Bae T, Liang H, Lan L. Modulation of MRSA virulence gene expression by the wall teichoic acid enzyme TarO. Nat Commun 2023; 14:1594. [PMID: 36949052 PMCID: PMC10032271 DOI: 10.1038/s41467-023-37310-5] [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: 07/01/2022] [Accepted: 03/10/2023] [Indexed: 03/24/2023] Open
Abstract
Phenol-soluble modulins (PSMs) and Staphylococcal protein A (SpA) are key virulence determinants for community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), an important human pathogen that causes a wide range of diseases. Here, using chemical and genetic approaches, we show that inhibition of TarO, the first enzyme in the wall teichoic acid (WTA) biosynthetic pathway, decreases the expression of genes encoding PSMs and SpA in the prototypical CA-MRSA strain USA300 LAC. Mechanistically, these effects are linked to the activation of VraRS two-component system that directly represses the expression of accessory gene regulator (agr) locus and spa. The activation of VraRS was due in part to the loss of the functional integrity of penicillin-binding protein 2 (PBP2) in a PBP2a-dependent manner. TarO inhibition can also activate VraRS in a manner independent of PBP2a. We provide multiple lines of evidence that accumulation of lipid-linked peptidoglycan precursors is a trigger for the activation of VraRS. In sum, our results reveal that WTA biosynthesis plays an important role in the regulation of virulence gene expression in CA-MRSA, underlining TarO as an attractive target for anti-virulence therapy. Our data also suggest that acquisition of PBP2a-encoding mecA gene can impart an additional regulatory layer for the modulation of key signaling pathways in S. aureus.
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Affiliation(s)
- Yunfu Lu
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049, China
| | - Feifei Chen
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- College of Life Science, Northwest University, Xi'an, 710127, China
| | - Qingmin Zhao
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049, China
| | - Qiao Cao
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- College of Life Science, Northwest University, Xi'an, 710127, China
| | - Rongrong Chen
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049, China
| | - Huiwen Pan
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049, China
| | - Yanhui Wang
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049, China
| | - Haixin Huang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Ruimin Huang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049, China
| | - Qian Liu
- Department of Laboratory Medicine, School of Medicine, Renji Hospital, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Min Li
- Department of Laboratory Medicine, School of Medicine, Renji Hospital, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Taeok Bae
- Department of Microbiology and Immunology, Indiana University School of Medicine-Northwest, Gary, IN, 46408, USA
| | - Haihua Liang
- College of Life Science, Northwest University, Xi'an, 710127, China.
- School of Medicine, Southern University of Science and Technology, Shenzhen, 518055, China.
| | - Lefu Lan
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China.
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049, China.
- College of Life Science, Northwest University, Xi'an, 710127, China.
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Disruption of the tagF Orthologue in the epa Locus Variable Region of Enterococcus faecalis Causes Cell Surface Changes and Suppresses an eep-Dependent Lysozyme Resistance Phenotype. J Bacteriol 2022; 204:e0024722. [PMID: 36094307 PMCID: PMC9578411 DOI: 10.1128/jb.00247-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The disease-producing capacity of the opportunistic pathogen Enterococcus faecalis is enhanced by the ability of the bacterium to evade killing by antimicrobial agents. Survival of E. faecalis in the presence of the human antimicrobial enzyme lysozyme is mediated in part by the site 2 metalloprotease Eep; however, a complete model of enterococcal lysozyme resistance has not been elucidated. To better understand the molecular basis for lysozyme resistance in E. faecalis, we analyzed Δeep suppressor mutants that acquire resistance to lysozyme through mutation of the gene OG1RF_11713, a predicted teichoic acid biosynthesis-encoding gene located within the variable region of the enterococcal polysaccharide antigen (epa) locus. Sequence comparisons revealed that OG1RF_11713 is most similar to the cytidine-5'-diphosphate (CDP)-glycerol:poly-(glycerolphosphate)glycerophosphotransferase TagF from Staphylococcus epidermidis. Inactivation of OG1RF_11713 in both the wild-type and Δeep genetic backgrounds was sufficient to increase the resistance of E. faecalis OG1RF to lysozyme. Minimal amounts of N-acetylgalactosamine were detectable in cell wall carbohydrate extracts of OG1RF_11713 deletion mutants, and this was associated with a reduction in negative cell surface charge. Targeted disruption of OG1RF_11713 was also associated with increased susceptibility to the antibiotic polymyxin B and membrane-targeting detergents and decreased susceptibility to the lantibiotic nisin. This work implicates OG1RF_11713 as a major determinant of cell envelope integrity and provides further validation that lysozyme resistance is intrinsically linked to the modification of enterococcal cell wall polysaccharides. IMPORTANCE Enterococcus faecalis is a leading cause of health-care-associated infections for which there are limited treatment options. E. faecalis is resistant to several antibiotics and to high concentrations of the human antimicrobial enzyme lysozyme. The molecular mechanisms that mediate lysozyme resistance in E. faecalis are complex and remain incompletely characterized. This work demonstrates that a gene located within the variable region of the enterococcal polysaccharide antigen locus of E. faecalis strain OG1RF (OG1RF_11713), which is predicted to encode a component of the teichoic acid biosynthesis machinery, is part of the lysozyme resistance circuitry and is important for enterococcal cell wall integrity. These findings suggest that OG1RF_11713 is a potential target for new therapeutic strategies to combat enterococcal infections.
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Tan S, Cho K, Nodwell JR. A defect in cell wall recycling confers antibiotic resistance and sensitivity in Staphylococcus aureus. J Biol Chem 2022; 298:102473. [PMID: 36089064 PMCID: PMC9547203 DOI: 10.1016/j.jbc.2022.102473] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 09/02/2022] [Accepted: 09/03/2022] [Indexed: 11/17/2022] Open
Abstract
WalKR is a two-component system that is essential for viability in Gram-positive bacteria that regulates the all-important autolysins in cell wall homeostasis. Further investigation of this essential system is important for identifying ways to address antibiotic resistance. Here, we show that a T101M mutation in walR confers a defect in autolysis, a thickened cell wall, and decreased susceptibility to antibiotics that target lipid II cycle, a phenotype that is reminiscent of the clinical resistance form known as vancomycin intermediate-resistant Staphylococcus aureus. Importantly, this is accompanied by dramatic sensitization to tunicamycin. We demonstrate that this phenotype is due to partial collapse of a pathway consisting of autolysins, AtlA and Sle1, a transmembrane sugar permease, MurP, and GlcNAc recycling enzymes, MupG and MurQ. We suggest that this causes a shortage of substrate for the peptidoglycan biosynthesis enzyme MraY, causing it to be hypersensitive to competitive inhibition by tunicamycin. In conclusion, our results constitute a new molecular model for antibiotic sensitivity in S. aureus and a promising new route for antibiotic discovery.
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Affiliation(s)
- Stephanie Tan
- Department of Biochemistry, MaRS Discovery District, University of Toronto, 661 University Avenue, Toronto, Ontario, Canada, M5G 1M1
| | - Kelvin Cho
- Department of Biochemistry, MaRS Discovery District, University of Toronto, 661 University Avenue, Toronto, Ontario, Canada, M5G 1M1
| | - Justin R Nodwell
- Department of Biochemistry, MaRS Discovery District, University of Toronto, 661 University Avenue, Toronto, Ontario, Canada, M5G 1M1.
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Potential of New Bacterial Strains for a Multiproduct Bioprocess Application: A Case Study Using Isolates of Lactic Acid Bacteria from Pineapple Silage of Costa Rican Agro-Industrial Residues. FERMENTATION 2022. [DOI: 10.3390/fermentation8080361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Lactic acid bacteria (LAB) with potential for the development of multi-product processes are necessary for the valorization of side streams obtained during the biotechnological production of lactic acid (LA). In this study, 14 LAB strains isolated from pineapple agro-industrial residues in Costa Rica were cultivated in microplates, and the six strains with the highest growth were selected for fermentation in microbioreactors to evaluate the production of LA and acetic acid, and the consumption of glucose. Lacticaseibacillus paracasei 6710 and L. paracasei 6714 presented the highest OD600 values (1.600 and 1.602, respectively); however, the highest LA (in g/L) production was observed in L. paracasei 6714 (14.50 ± 0.20) and 6712 (14.67 ± 0.42). L. paracasei 6714 was selected for bioreactor fermentation and reached a maximum OD600 of 6.3062 ± 0.141, with a LA yield of 84.9% and a productivity of 1.06 g L−1 h−1 after 21 h of fermentation. Finally, lipoteichoic acid (LTA) detection from biomass was performed and the antimicrobial activity of the compounds present in the supernatant was studied. LTA was detected from L. paracasei 6714 biomass, and its supernatant caused significant inhibition of foodborne surrogate microorganisms. LAB isolated from pineapple silage have biotechnological potential for multiproduct processes.
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10
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Sionov RV, Banerjee S, Bogomolov S, Smoum R, Mechoulam R, Steinberg D. Targeting the Achilles’ Heel of Multidrug-Resistant Staphylococcus aureus by the Endocannabinoid Anandamide. Int J Mol Sci 2022; 23:ijms23147798. [PMID: 35887146 PMCID: PMC9319909 DOI: 10.3390/ijms23147798] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/10/2022] [Accepted: 07/12/2022] [Indexed: 02/06/2023] Open
Abstract
Antibiotic-resistant Staphylococcus aureus is a major health issue that requires new therapeutic approaches. Accumulating data suggest that it is possible to sensitize these bacteria to antibiotics by combining them with inhibitors targeting efflux pumps, the low-affinity penicillin-binding protein PBP2a, cell wall teichoic acid, or the cell division protein FtsZ. We have previously shown that the endocannabinoid Anandamide (N-arachidonoylethanolamine; AEA) could sensitize drug-resistant S. aureus to a variety of antibiotics, among others, through growth arrest and inhibition of drug efflux. Here, we looked at biochemical alterations caused by AEA. We observed that AEA increased the intracellular drug concentration of a fluorescent penicillin and augmented its binding to membrane proteins with concomitant altered membrane distribution of these proteins. AEA also prevented the secretion of exopolysaccharides (EPS) and reduced the cell wall teichoic acid content, both processes known to require transporter proteins. Notably, AEA was found to inhibit membrane ATPase activity that is necessary for transmembrane transport. AEA did not affect the membrane GTPase activity, and the GTPase cell division protein FtsZ formed the Z-ring of the divisome normally in the presence of AEA. Rather, AEA caused a reduction in murein hydrolase activities involved in daughter cell separation. Altogether, this study shows that AEA affects several biochemical processes that culminate in the sensitization of the drug-resistant bacteria to antibiotics.
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Affiliation(s)
- Ronit Vogt Sionov
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
- Correspondence:
| | - Shreya Banerjee
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
| | - Sergei Bogomolov
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
| | - Reem Smoum
- Institute for Drug Research, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (R.S.); (R.M.)
| | - Raphael Mechoulam
- Institute for Drug Research, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (R.S.); (R.M.)
| | - Doron Steinberg
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
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11
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Xiong M, Chen L, Zhao J, Xiao X, Zhou J, Fang F, Li X, Pan Y, Li Y. Genomic Analysis of the Unusual Staphylococcus aureus ST630 Isolates Harboring WTA Glycosyltransferase Genes tarM and tagN. Microbiol Spectr 2022; 10:e0150121. [PMID: 35170993 PMCID: PMC8849055 DOI: 10.1128/spectrum.01501-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 01/26/2022] [Indexed: 12/25/2022] Open
Abstract
Staphylococcus aureus (S. aureus) can cause a broad spectrum of diseases ranging from skin infections to life-threatening diseases in both community and hospital settings. The surface-exposed wall teichoic acid (WTA) has a strong impact on host interaction, pathogenicity, horizontal gene transfer, and biofilm formation in S. aureus. The unusual S. aureus ST630 strains containing both ribitol-phosphate (RboP) WTA glycosyltransferase gene tarM and glycerol-phosphate (GroP) WTA glycosyltransferase gene tagN have been found recently. Native PAGE analysis showed that the WTA of tagN, tarM-encoding ST630 strains migrated slower than that of non-tagN-encoding ST630 strains, indicating the differences in WTA structure. Some mobile genetic elements (MGEs) such as the unique GroP-WTA biosynthetic gene cluster (SaGroWI), SCCmec element, and prophages that probably originated from the CoNS were identified in tagN, tarM-encoding ST630 strains. The SaGroWI element was first defined in S. aureus ST395 strain, which was refractory to exchange MGEs with typical RboP-WTA expressing S. aureus but could undergo horizontal gene transfer events with other species and genera via the specific bacteriophage Φ187. Overall, our data indicated that this rare ST630 was prone to acquire DNA from CoNS and might serve as a novel hub for the exchange of MGEs between CoNS and S. aureus. IMPORTANCE The structure of wall-anchored glycopolymers wall teichoic acid (WTA) produced by most Gram-positive bacteria is highly variable. While most dominant Staphylococcus aureus lineages produce poly-ribitol-phosphate (RboP) WTA, the tagN, tarM-encoding ST630 lineage probably has a poly-glycerol-phosphate (GroP) WTA backbone like coagulase-negative staphylococci (CoNS). There is growing evidence that staphylococcal horizontal gene transfer depends largely on transducing helper phages via WTA as the receptor. The structural difference of WTA greatly affects the transfer of mobile genetic elements among various bacteria. With the growing advances in sequencing and analysis technologies, genetic analysis has revolutionized research activities in the field of the important pathogen S. aureus. Here, we analyzed the molecular characteristics of ST630 and found an evolutionary link between ST630 and CoNS. Elucidating the genetic information of ST630 lineage will contribute to understanding the emergence and diversification of new pathogenic strains in S. aureus.
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Affiliation(s)
- Mengyuan Xiong
- Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Liangjun Chen
- Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Jin Zhao
- Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Xiao Xiao
- Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Junying Zhou
- Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Fang Fang
- Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Xinwei Li
- Medical School of Zhengzhou University, Zhengzhou, China
| | - Yunbao Pan
- Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Engineering Center for Infectious Disease Prevention, Control and Treatment, Wuhan, China
| | - Yirong Li
- Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Engineering Center for Infectious Disease Prevention, Control and Treatment, Wuhan, China
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12
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Glucose Decoration on Wall Teichoic Acid Is Required for Phage Adsorption and InlB-Mediated Virulence in Listeria ivanovii. J Bacteriol 2021; 203:e0013621. [PMID: 34096780 PMCID: PMC8297528 DOI: 10.1128/jb.00136-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Listeria ivanovii (Liv) is an intracellular Gram-positive pathogen that primarily infects ruminants but also occasionally causes enteric infections in humans. Albeit rare, this bacterium possesses the capacity to cross the intestinal epithelium of humans, similar to its more frequently pathogenic cousin, Listeria monocytogenes (Lmo). Recent studies in Lmo have shown that specific glycosyl modifications on the cell wall-associated glycopolymers (termed wall teichoic acid [WTA]) of Lmo are responsible for bacteriophage adsorption and retention of the major virulence factor internalin B (InlB). However, the relationship between InlB and WTA in Liv remains unclear. Here, we report the identification of the unique gene liv1070, which encodes a putative glucosyltransferase in the polycistronic WTA gene cluster of the Liv WSLC 3009 genome. We found that in-frame deletion of liv1070 led to loss of the glucose substitution on WTA, as revealed by ultraperformance liquid chromatography-mass spectrometry (UPLC-MS) analysis. Interestingly, the glucose-deficient mutant became resistant to phage B025 infection due to an inability of the phage to adsorb to the bacterial surface, a binding process mediated by the receptor-binding protein B025_Gp17. As expected, deletion of liv1070 led to loss of InlB retention on the bacterial cell wall, which corresponded to a drastic decrease in cellular invasion. Genetic complementation of liv1070 restored the characteristic phenotypes, including glucose decoration, phage adsorption, and cellular invasion. Taken together, our data demonstrate that an interplay between phage, bacteria, and host cells also exists in Listeria ivanovii, suggesting that the trade-off between phage resistance and virulence attenuation may be a general feature in the genus Listeria. IMPORTANCE Listeria ivanovii is a Gram-positive bacterial pathogen known to cause enteric infection in rodents and ruminants and occasionally in immunocompromised humans. Recent investigations revealed that in its better-known cousin Listeria monocytogenes, strains develop resistance to bacteriophage attack due to loss of glycosylated surface receptors, which subsequently results in disconnection of one of the bacterium's major virulence factors, InlB. However, the situation in L. ivanovii remains unclear. Here, we show that L. ivanovii acquires phage resistance following deletion of a unique glycosyltransferase. This deletion also leads to dysfunction of InlB, making the resulting strain unable to invade host cells. Overall, this study suggests that the interplay between phage, bacteria, and the host may be a feature common to the genus Listeria.
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13
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Walsh L, Johnson CN, Hill C, Ross RP. Efficacy of Phage- and Bacteriocin-Based Therapies in Combatting Nosocomial MRSA Infections. Front Mol Biosci 2021; 8:654038. [PMID: 33996906 PMCID: PMC8116899 DOI: 10.3389/fmolb.2021.654038] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 04/07/2021] [Indexed: 12/21/2022] Open
Abstract
Staphylococcus aureus is a pathogen commonly found in nosocomial environments where infections can easily spread - especially given the reduced immune response of patients and large overlap between personnel in charge of their care. Although antibiotics are available to treat nosocomial infections, the increased occurrence of antibiotic resistance has rendered many treatments ineffective. Such is the case for methicillin resistant S. aureus (MRSA), which has continued to be a threat to public health since its emergence. For this reason, alternative treatment technologies utilizing antimicrobials such as bacteriocins, bacteriophages (phages) and phage endolysins are being developed. These antimicrobials provide an advantage over antibiotics in that many have narrow inhibition spectra, enabling treatments to be selected based on the target (pathogenic) bacterium while allowing for survival of commensal bacteria and thus avoiding collateral damage to the microbiome. Bacterial resistance to these treatments occurs less frequently than with antibiotics, particularly in circumstances where combinatory antimicrobial therapies are used. Phage therapy has been well established in Eastern Europe as an effective treatment against bacterial infections. While there are no Randomized Clinical Trials (RCTs) to our knowledge examining phage treatment of S. aureus infections that have completed all trial phases, numerous clinical trials are underway, and several commercial phage preparations are currently available to treat S. aureus infections. Bacteriocins have primarily been used in the food industry for bio-preservation applications. However, the idea of repurposing bacteriocins for human health is an attractive one considering their efficacy against many bacterial pathogens. There are concerns about the ability of bacteriocins to survive the gastrointestinal tract given their proteinaceous nature, however, this obstacle may be overcome by altering the administration route of the therapy through encapsulation, or by bioengineering protease-resistant variants. Obstacles such as enzymatic digestion are less of an issue for topical/local administration, for example, application to the surface of the skin. Bacteriocins have also shown impressive synergistic effects when used in conjunction with other antimicrobials, including antibiotics, which may allow antibiotic-based therapies to be used more sparingly with less resistance development. This review provides an updated account of known bacteriocins, phages and phage endolysins which have demonstrated an impressive ability to kill S. aureus strains. In particular, examples of antimicrobials with the ability to target MRSA strains and their subsequent use in a clinical setting are outlined.
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Affiliation(s)
- Lauren Walsh
- School of Microbiology, University College Cork, Cork, Ireland.,APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Crystal N Johnson
- School of Microbiology, University College Cork, Cork, Ireland.,APC Microbiome Ireland, University College Cork, Cork, Ireland.,Teagasc Food Research Centre, Moorepark, Cork, Ireland
| | - Colin Hill
- School of Microbiology, University College Cork, Cork, Ireland.,APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - R Paul Ross
- School of Microbiology, University College Cork, Cork, Ireland.,APC Microbiome Ireland, University College Cork, Cork, Ireland.,Teagasc Food Research Centre, Moorepark, Cork, Ireland
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14
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Li FKK, Gale RT, Petrotchenko EV, Borchers CH, Brown ED, Strynadka NCJ. Crystallographic analysis of TarI and TarJ, a cytidylyltransferase and reductase pair for CDP-ribitol synthesis in Staphylococcus aureus wall teichoic acid biogenesis. J Struct Biol 2021; 213:107733. [PMID: 33819634 DOI: 10.1016/j.jsb.2021.107733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 03/29/2021] [Accepted: 03/30/2021] [Indexed: 11/18/2022]
Abstract
The cell wall of many pathogenic Gram-positive bacteria contains ribitol-phosphate wall teichoic acid (WTA), a polymer that is linked to virulence and regulation of essential physiological processes including cell division. CDP-ribitol, the activated precursor for ribitol-phosphate polymerization, is synthesized by a cytidylyltransferase and reductase pair known as TarI and TarJ, respectively. In this study, we present crystal structures of Staphylococcus aureus TarI and TarJ in their apo forms and in complex with substrates and products. The TarI structures illustrate the mechanism of CDP-ribitol synthesis from CTP and ribitol-phosphate and reveal structural changes required for substrate binding and catalysis. Insights into the upstream step of ribulose-phosphate reduction to ribitol-phosphate is provided by the structures of TarJ. Furthermore, we propose a general topology of the enzymes in a heterotetrameric form built using restraints from crosslinking mass spectrometry analysis. Together, our data present molecular details of CDP-ribitol production that may aid in the design of inhibitors against WTA biosynthesis.
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Affiliation(s)
- Franco K K Li
- Department of Biochemistry and Molecular Biology and Centre for Blood Research, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Robert T Gale
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8N 3ZS, Canada
| | - Evgeniy V Petrotchenko
- Segal Cancer Proteomics Centre, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, Quebec H3T 1E2, Canada; Center for Computational and Data-Intensive Science and Engineering, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Christoph H Borchers
- Segal Cancer Proteomics Centre, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, Quebec H3T 1E2, Canada; Center for Computational and Data-Intensive Science and Engineering, Skolkovo Institute of Science and Technology, Moscow 121205, Russia; Gerald Bronfman Department of Oncology, Jewish General Hospital, McGill University, Montreal, Quebec H3T 1E2, Canada
| | - Eric D Brown
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8N 3ZS, Canada
| | - Natalie C J Strynadka
- Department of Biochemistry and Molecular Biology and Centre for Blood Research, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
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15
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Fisher JF, Mobashery S. β-Lactams against the Fortress of the Gram-Positive Staphylococcus aureus Bacterium. Chem Rev 2021; 121:3412-3463. [PMID: 33373523 PMCID: PMC8653850 DOI: 10.1021/acs.chemrev.0c01010] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The biological diversity of the unicellular bacteria-whether assessed by shape, food, metabolism, or ecological niche-surely rivals (if not exceeds) that of the multicellular eukaryotes. The relationship between bacteria whose ecological niche is the eukaryote, and the eukaryote, is often symbiosis or stasis. Some bacteria, however, seek advantage in this relationship. One of the most successful-to the disadvantage of the eukaryote-is the small (less than 1 μm diameter) and nearly spherical Staphylococcus aureus bacterium. For decades, successful clinical control of its infection has been accomplished using β-lactam antibiotics such as the penicillins and the cephalosporins. Over these same decades S. aureus has perfected resistance mechanisms against these antibiotics, which are then countered by new generations of β-lactam structure. This review addresses the current breadth of biochemical and microbiological efforts to preserve the future of the β-lactam antibiotics through a better understanding of how S. aureus protects the enzyme targets of the β-lactams, the penicillin-binding proteins. The penicillin-binding proteins are essential enzyme catalysts for the biosynthesis of the cell wall, and understanding how this cell wall is integrated into the protective cell envelope of the bacterium may identify new antibacterials and new adjuvants that preserve the efficacy of the β-lactams.
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Affiliation(s)
- Jed F Fisher
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame Indiana 46556, United States
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame Indiana 46556, United States
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16
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Guo Y, Pfahler NM, Völpel SL, Stehle T. Cell wall glycosylation in Staphylococcus aureus: targeting the tar glycosyltransferases. Curr Opin Struct Biol 2021; 68:166-174. [PMID: 33540375 DOI: 10.1016/j.sbi.2021.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 12/14/2020] [Accepted: 01/07/2021] [Indexed: 11/26/2022]
Abstract
Peptidoglycan (PG) is the major structural polymer of the bacterial cell wall. The PG layer of gram-positive bacterial pathogens such as Staphylococcus aureus (S. aureus) is permeated with anionic glycopolymers known as wall teichoic acids (WTAs) and lipoteichoic acids (LTAs). In S. aureus, the WTA backbone typically consists of repeating ribitol-5-phosphate units, which are modified by enzymes that introduce glycosylation as well as amino acids at different locations. These modifications are key determinants of phage adhesion, bacterial biofilm formation and virulence of S. aureus. In this review, we examine differences in WTA structures in gram-positive bacteria, focusing in particular on three enzymes, TarM, TarS, and TarP that glycosylate the WTA of S. aureus at different locations. Infections with S. aureus pose an increasing threat to human health, particularly through the emergence of multidrug-resistant strains. Recently obtained structural information on TarM, TarS and TarP has helped to better understand the strategies used by S. aureus to establish resistance and to evade host defense mechanisms. Moreover, structures of complexes with poly-RboP and its analogs can serve as a platform for the development of new inhibitors that could form a basis for the development of antibiotic agents.
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Affiliation(s)
- Yinglan Guo
- Interfaculty Institute of Biochemistry, University of Tübingen, Germany
| | - Nina M Pfahler
- Interfaculty Institute of Biochemistry, University of Tübingen, Germany
| | - Simon L Völpel
- Interfaculty Institute of Biochemistry, University of Tübingen, Germany
| | - Thilo Stehle
- Interfaculty Institute of Biochemistry, University of Tübingen, Germany; Vanderbilt University School of Medicine, Nashville, USA.
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17
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Wu X, Han J, Gong G, Koffas MAG, Zha J. Wall teichoic acids: physiology and applications. FEMS Microbiol Rev 2020; 45:6019871. [DOI: 10.1093/femsre/fuaa064] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 12/01/2020] [Indexed: 12/21/2022] Open
Abstract
ABSTRACT
Wall teichoic acids (WTAs) are charged glycopolymers containing phosphodiester-linked polyol units and represent one of the major components of Gram-positive cell envelope. WTAs have important physiological functions in cell division, gene transfer, surface adhesion, drug resistance and biofilm formation, and are critical virulence factors and vital determinants in mediating cell interaction with and tolerance to environmental factors. Here, we first briefly introduce WTA structure, biosynthesis and its regulation, and then summarize in detail four major physiological roles played by WTAs, i.e. WTA-mediated resistance to antimicrobials, virulence to mammalian cells, interaction with bacteriolytic enzymes and regulation of cell metabolism. We also review the applications of WTAs in these fields that are closely related to the human society, including antibacterial drug discovery targeting WTA biosynthesis, development of vaccines and antibodies regarding WTA-mediated pathogenicity, specific and sensitive detection of pathogens in food using WTAs as a surface epitope and regulation of WTA-related pathways for efficient microbial production of useful compounds. We also point out major problems remaining in these fields, and discuss some possible directions in the future exploration of WTA physiology and applications.
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Affiliation(s)
- Xia Wu
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
| | - Jing Han
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
| | - Guoli Gong
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
| | - Mattheos A G Koffas
- Center for Biotechnology and Interdisciplinary Studies, Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Jian Zha
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
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18
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Wall Teichoic Acid in Staphylococcus aureus Host Interaction. Trends Microbiol 2020; 28:985-998. [DOI: 10.1016/j.tim.2020.05.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 02/07/2023]
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19
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Lipoteichoic acid polymer length is determined by competition between free starter units. Proc Natl Acad Sci U S A 2020; 117:29669-29676. [PMID: 33172991 DOI: 10.1073/pnas.2008929117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Carbohydrate polymers exhibit incredible chemical and structural diversity, yet are produced by polymerases without a template to guide length and composition. As the length of carbohydrate polymers is critical for their biological functions, understanding the mechanisms that determine polymer length is an important area of investigation. Most Gram-positive bacteria produce anionic glycopolymers called lipoteichoic acids (LTA) that are synthesized by lipoteichoic acid synthase (LtaS) on a diglucosyl-diacylglycerol (Glc2DAG) starter unit embedded in the extracellular leaflet of the cell membrane. LtaS can use phosphatidylglycerol (PG) as an alternative starter unit, but PG-anchored LTA polymers are significantly longer, and cells that make these abnormally long polymers exhibit major defects in cell growth and division. To determine how LTA polymer length is controlled, we reconstituted Staphylococcus aureus LtaS in vitro. We show that polymer length is an intrinsic property of LtaS that is directly regulated by the identity and concentration of lipid starter units. Polymerization is processive, and the overall reaction rate is substantially faster for the preferred Glc2DAG starter unit, yet the use of Glc2DAG leads to shorter polymers. We propose a simple mechanism to explain this surprising result: free starter units terminate polymerization by displacing the lipid anchor of the growing polymer from its binding site on the enzyme. Because LtaS is conserved across most Gram-positive bacteria and is important for survival, this reconstituted system should be useful for characterizing inhibitors of this key cell envelope enzyme.
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20
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Eskhan AO, Abu-Lail NI. Force-Averaging DLVO Model Predictions of the Adhesion Strengths Quantified for Pathogenic Listeria monocytogenes EGDe Grown under Variable pH Stresses. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:8947-8964. [PMID: 32633976 DOI: 10.1021/acs.langmuir.0c01500] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The roles of the bacterial surface biopolymers of pathogenic Listeria monocytogenes EGDe grown under variable pH conditions in governing their adhesion to a model surface of silicon nitride were investigated using atomic force microscopy under water. Our results indicated that the adhesion forces were the highest for cells cultured in media adjusted to pH 7 followed by 1.39, 1.49, 1.57, and 2.18-fold reductions at pH 6, 8, 9, and 5, respectively. Adhesion energies followed the same trends with 1.35, 1.67, 2.20, and 2.79-fold reductions in energies at pH 6, 8, 9, and 5, respectively, compared to the energy measured at pH 7. Furthermore, the structural properties of the bacterial surface biopolymer brush represented by the biopolymer brush thickness (Lo) and the molecular density (Γ) were determined by fitting a steric model of repulsion to the approach force-distance data. The Lo values followed the same trends as adhesion forces and energies, with thickness being highest at pH 7 followed by 1.82, 2.99, 3.11, and 4.66-fold reductions at pH 6, 8, 9, and 5, respectively. Γ was the highest at pH 5 and was followed by 1.26, 1.27, 1.70, and 2.82-fold reductions at pH 8, 9, 6, and 7, respectively. Our results indicated that bacterial adhesion forces and energies increased linearly with the product of Lo and Γ representing the number of biopolymers per unit length of the bacterial surface. To predict the adhesion forces and energies measured, a force-averaging model of the soft-particle analysis of the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory was used. In addition to the standard parameters accounted for in the soft-particle analysis of the DLVO theory such as surface potential, hydrophobicity, and size, this averaging model incorporates in it structural bacterial parameters such as Lo and Γ as well as a surface coverage factor (ϕ) that represents the fraction of the bacterial surface covered by biopolymers. When the soft-particle analysis of DLVO was considered, repulsive hydrogen bond strengths were predicted at close distances of approach (<0.3 nm). In comparison, the force-averaging model predicted that attractive hydrogen bonds dominate the bacterial adhesion strengths quantified. The highest adhesion quantified for cells grown at pH 7 was related to longer and more spaced biopolymers, higher contents of cellular carbohydrates, and more hydrophilic biopolymers, each of which contributes to higher possibilities for hydrogen bonding formation. These results are significant in designing new strategies that aim at controlling bacterial adhesion to surfaces.
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Affiliation(s)
- Asma O Eskhan
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington 99164, United States
| | - Nehal I Abu-Lail
- Department of Biomedical Engineering and Chemical Engineering, The University of Texas at San Antonio, San Antonio, Texas, 78249, United States
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21
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Hesser AR, Matano LM, Vickery CR, Wood BM, Santiago AG, Morris HG, Do T, Losick R, Walker S. The length of lipoteichoic acid polymers controls Staphylococcus aureus cell size and envelope integrity. J Bacteriol 2020; 202:JB.00149-20. [PMID: 32482719 PMCID: PMC8404710 DOI: 10.1128/jb.00149-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 05/22/2020] [Indexed: 02/08/2023] Open
Abstract
The opportunistic pathogen Staphylococcus aureus is protected by a cell envelope that is crucial for viability. In addition to peptidoglycan, lipoteichoic acid (LTA) is an especially important component of the S. aureus cell envelope. LTA is an anionic polymer anchored to a glycolipid in the outer leaflet of the cell membrane. It was known that deleting the gene for UgtP, the enzyme that makes this glycolipid anchor, causes cell growth and division defects. In Bacillus subtilis, growth abnormalities from the loss of ugtP have been attributed to both the absence of the encoded protein and to the loss of its products. Here, we show that growth defects in S. aureus ugtP deletion mutants are due to the long, abnormal LTA polymer that is produced when the glycolipid anchor is missing from the outer leaflet of the membrane. Dysregulated cell growth leads to defective cell division, and these phenotypes are corrected by mutations in the LTA polymerase, ltaS, that reduce polymer length. We also show that S. aureus mutants with long LTA are sensitized to cell wall hydrolases, beta-lactam antibiotics, and compounds that target other cell envelope pathways. We conclude that control of LTA polymer length is important for S. aureus physiology and promotes survival under stressful conditions, including antibiotic stress.IMPORTANCE Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of community- and hospital-acquired infections and is responsible for a large fraction of deaths caused by antibiotic-resistant bacteria. S. aureus is surrounded by a complex cell envelope that protects it from antimicrobial compounds and other stresses. Here we show that controlling the length of an essential cell envelope polymer, lipoteichoic acid, is critical for controlling S. aureus cell size and cell envelope integrity. We also show that genes involved in LTA length regulation are required for resistance to beta-lactam antibiotics in MRSA. The proteins encoded by these genes may be targets for combination therapy with an appropriate beta-lactam.
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Affiliation(s)
- Anthony R Hesser
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Leigh M Matano
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | | | - B McKay Wood
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Ace George Santiago
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Heidi G Morris
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Truc Do
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Richard Losick
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Suzanne Walker
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
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Caudill ER, Hernandez RT, Johnson KP, O'Rourke JT, Zhu L, Haynes CL, Feng ZV, Pedersen JA. Wall teichoic acids govern cationic gold nanoparticle interaction with Gram-positive bacterial cell walls. Chem Sci 2020; 11:4106-4118. [PMID: 34122876 PMCID: PMC8152635 DOI: 10.1039/c9sc05436g] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 03/20/2020] [Indexed: 11/21/2022] Open
Abstract
Molecular-level understanding of nanomaterial interactions with bacterial cell surfaces can facilitate design of antimicrobial and antifouling surfaces and inform assessment of potential consequences of nanomaterial release into the environment. Here, we investigate the interaction of cationic nanoparticles with the main surface components of Gram-positive bacteria: peptidoglycan and teichoic acids. We employed intact cells and isolated cell walls from wild type Bacillus subtilis and two mutant strains differing in wall teichoic acid composition to investigate interaction with gold nanoparticles functionalized with cationic, branched polyethylenimine. We quantified nanoparticle association with intact cells by flow cytometry and determined sites of interaction by solid-state 31P- and 13C-NMR spectroscopy. We find that wall teichoic acid structure and composition were important determinants for the extent of interaction with cationic gold nanoparticles. The nanoparticles interacted more with wall teichoic acids from the wild type and mutant lacking glucose in its wall teichoic acids than those from the mutant having wall teichoic acids lacking alanine and exhibiting more restricted molecular motion. Our experimental evidence supports the interpretation that electrostatic forces contributed to nanoparticle-cell interactions and that the accessibility of negatively charged moieties in teichoic acid chains influences the degree of interaction. The approaches employed in this study can be applied to engineered nanomaterials differing in core composition, shape, or surface functional groups as well as to other types of bacteria to elucidate the influence of nanoparticle and cell surface properties on interactions with Gram-positive bacteria.
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Affiliation(s)
- Emily R Caudill
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
| | | | - Kyle P Johnson
- Department of Chemistry, University of Minnesota Minneapolis MN 55455 USA
| | - James T O'Rourke
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
| | - Lingchao Zhu
- Department of Chemistry, University of Pennsylvania 231 S 34th St Philadelphia PA 19104 USA
| | - Christy L Haynes
- Department of Chemistry, University of Minnesota Minneapolis MN 55455 USA
| | - Z Vivian Feng
- Chemistry Department, Augsburg University Minneapolis MN 55454 USA
| | - Joel A Pedersen
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
- Environmental Chemistry and Technology Program, University of Wisconsin-Madison 660 North Part Street Madison WI 53706 USA
- Department of Soil Science, University of Wisconsin-Madison 1525 Observatory Drive Madison WI 53706 USA
- Department of Civil & Environmental Engineering, University of Wisconsin-Madison 1415 Engineering Drive Madison WI 53706 USA
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Keinhörster D, George SE, Weidenmaier C, Wolz C. Function and regulation of Staphylococcus aureus wall teichoic acids and capsular polysaccharides. Int J Med Microbiol 2019; 309:151333. [DOI: 10.1016/j.ijmm.2019.151333] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 07/09/2019] [Accepted: 07/17/2019] [Indexed: 01/05/2023] Open
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Abstract
The chapter about the Gram-positive bacterial cell wall gives a brief historical background on the discovery of Gram-positive cell walls and their constituents and microscopic methods applied for studying the Gram-positive cell envelope. Followed by the description of the different chemical building blocks of peptidoglycan and the biosynthesis of the peptidoglycan layers and high turnover of peptidoglycan during bacterial growth. Lipoteichoic acids and wall teichoic acids are highlighted as major components of the cell wall. Characterization of capsules and the formation of extracellular vesicles by Gram-positive bacteria close the section on cell envelopes which have a high impact on bacterial pathogenesis. In addition, the specialized complex and unusual cell wall of mycobacteria is introduced thereafter. Next a short back view is given on the development of electron microscopic examinations for studying bacterial cell walls. Different electron microscopic techniques and methods applied to examine bacterial cell envelopes are discussed in the view that most of the illustrated methods should be available in a well-equipped life sciences orientated electron microscopic laboratory. In addition, newly developed and mostly well-established cryo-methods like high-pressure freezing and freeze-substitution (HPF-FS) and cryo-sections of hydrated vitrified bacteria (CEMOVIS, Cryo-electron microscopy of vitreous sections) are described. At last, modern cryo-methods like cryo-electron tomography (CET) and cryo-FIB-SEM milling (focus ion beam-scanning electron microscopy) are introduced which are available only in specialized institutions, but at present represent the best available methods and techniques to study Gram-positive cell walls under close-to-nature conditions in great detail and at high resolution.
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Affiliation(s)
- Manfred Rohde
- Helmholtz Centre for Infection Research, HZI, Central Facility for Microscopy, ZEIM, Braunschweig, Germany
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Azam AH, Tanji Y. Peculiarities of Staphylococcus aureus phages and their possible application in phage therapy. Appl Microbiol Biotechnol 2019; 103:4279-4289. [PMID: 30997551 DOI: 10.1007/s00253-019-09810-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 03/07/2019] [Accepted: 03/31/2019] [Indexed: 12/21/2022]
Abstract
Bacteriophage has become an attractive alternative for the treatment of antibiotic-resistant Staphylococcus aureus. For the success of phage therapy, phage host range is an important criterion when considering a candidate phage. Most reviews of S. aureus (SA) phages have focused on their impact on host evolution, especially their contribution to the spread of virulence genes and pathogenesis factors. The potential therapeutic use of SA phages, especially detailed characterizations of host recognition mechanisms, has not been extensively reviewed so far. In this report, we provide updates on the study of SA phages, focusing on host recognition mechanisms with the recent discovery of phage receptor-binding proteins (RBPs) and the possible applications of SA phages in phage therapy.
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Affiliation(s)
- Aa Haeruman Azam
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 J2-15, Nagatsuta-cho, Midori-ku, Yokohama, 226-8501, Japan
| | - Yasunori Tanji
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 J2-15, Nagatsuta-cho, Midori-ku, Yokohama, 226-8501, Japan.
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Bacteriophage-host arm race: an update on the mechanism of phage resistance in bacteria and revenge of the phage with the perspective for phage therapy. Appl Microbiol Biotechnol 2019; 103:2121-2131. [PMID: 30680434 DOI: 10.1007/s00253-019-09629-x] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 12/25/2018] [Accepted: 12/27/2018] [Indexed: 12/20/2022]
Abstract
Due to a constant attack by phage, bacteria in the environment have evolved diverse mechanisms to defend themselves. Several reviews on phage resistance mechanisms have been published elsewhere. Thanks to the advancement of molecular techniques, several new phage resistance mechanisms were recently identified. For the practical phage therapy, the emergence of phage-resistant bacteria could be an obstacle. However, unlike antibiotic, phages could evolve a mechanism to counter-adapt against phage-resistant bacteria. In this review, we summarized the most recent studies of the phage-bacteria arm race with the perspective of future applications of phages as antimicrobial agents.
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Kho K, Meredith TC. Extraction and Analysis of Bacterial Teichoic Acids. Bio Protoc 2018; 8:e3078. [PMID: 34532535 DOI: 10.21769/bioprotoc.3078] [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: 08/01/2018] [Revised: 10/29/2018] [Accepted: 10/30/2018] [Indexed: 11/02/2022] Open
Abstract
Teichoic acids (TA) are anionic polymers comprised of polyol phosphate repeat units that are abundant in the cell wall of Gram-positive bacteria. Both wall teichoic acid (WTA) and lipoteichoic acid (LTA) play important roles in regulating cell wall remodeling as well as conferring antibiotic resistance. To analyze TA, we describe a polyacrylamide gel electrophoresis (PAGE) method for both WTA and LTA. To extract crude WTA, the peptidoglycan sacculus is first isolated and WTA is then liberated by hydrolysis. LTA is extracted by 1-butanol and pre-treated with lipase to prevent aggregation and improve single-band resolution by PAGE. Crude extracts of both TAs are then subjected to PAGE followed by Alcian blue and silver staining. These protocols are easily adoptable by laboratories interested in rapidly analyzing TAs and can be used determine the relative abundance, relative polymer length and whether TAs are glycosylated. More detailed TA structural and compositional information can be obtained using the described purification protocols by nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry (ESI-MS) analysis.
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Affiliation(s)
- Kelvin Kho
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Timothy C Meredith
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA
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Azam AH, Hoshiga F, Takeuchi I, Miyanaga K, Tanji Y. Analysis of phage resistance in Staphylococcus aureus SA003 reveals different binding mechanisms for the closely related Twort-like phages ɸSA012 and ɸSA039. Appl Microbiol Biotechnol 2018; 102:8963-8977. [DOI: 10.1007/s00253-018-9269-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 07/15/2018] [Accepted: 07/22/2018] [Indexed: 02/01/2023]
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29
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Zhu X, Liu D, Singh AK, Drolia R, Bai X, Tenguria S, Bhunia AK. Tunicamycin Mediated Inhibition of Wall Teichoic Acid Affects Staphylococcus aureus and Listeria monocytogenes Cell Morphology, Biofilm Formation and Virulence. Front Microbiol 2018; 9:1352. [PMID: 30034372 PMCID: PMC6043806 DOI: 10.3389/fmicb.2018.01352] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 06/05/2018] [Indexed: 12/14/2022] Open
Abstract
The emergence of bacterial resistance to therapeutic antibiotics limits options for treatment of common microbial diseases. Subinhibitory antibiotics dosing, often aid in the emergence of resistance, but its impact on pathogen’s physiology and pathogenesis is not well understood. Here we investigated the effect of tunicamycin, a cell wall teichoic acid (WTA) biosynthesis inhibiting antibiotic at the subinhibitory dosage on Staphylococcus aureus and Listeria monocytogenes physiology, antibiotic cross-resistance, biofilm-formation, and virulence. Minimum inhibitory concentration (MIC) of tunicamycin to S. aureus and L. monocytogenes was 20–40 μg/ml and 2.5–5 μg/ml, respectively, and the subinhibitory concentration was 2.5–5 μg/ml and 0.31–0.62 μg/ml, respectively. Tunicamycin pre-exposure reduced cellular WTA levels by 18–20% and affected bacterial cell wall ultrastructure, cell membrane permeability, morphology, laser-induced colony scatter signature, and bacterial ability to form biofilms. It also induced a moderate level of cross-resistance to tetracycline, ampicillin, erythromycin, and meropenem for S. aureus, and ampicillin, erythromycin, vancomycin, and meropenem for L. monocytogenes. Pre-treatment of bacterial cells with subinhibitory concentrations of tunicamycin also significantly reduced bacterial adhesion to and invasion into an enterocyte-like Caco-2 cell line, which is supported by reduced expression of key virulence factors, Internalin B (InlB) and Listeria adhesion protein (LAP) in L. monocytogenes, and a S. aureus surface protein A (SasA) in S. aureus. Tunicamycin-treated bacteria or the bacterial WTA preparation suppressed NF-κB and inflammatory cytokine production (TNFα, and IL-6) from murine macrophage cell line (RAW 264.7) indicating the reduced WTA level possibly attenuates an inflammatory response. These results suggest that at the subinhibitory dosage, tunicamycin-mediated inhibition of WTA biosynthesis interferes with cell wall structure, pathogens infectivity and inflammatory response, and ability to form biofilms but promotes the development of antibiotic cross-resistance.
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Affiliation(s)
- Xingyue Zhu
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States.,College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing, China
| | - Dongqi Liu
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Atul K Singh
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Rishi Drolia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Xingjian Bai
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Shivendra Tenguria
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Arun K Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States.,Department of Comparative Pathobiology, Purdue University, West Lafayette, IN, United States
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Unprotonated Short-Chain Alkylamines Inhibit Staphylolytic Activity of Lysostaphin in a Wall Teichoic Acid-Dependent Manner. Appl Environ Microbiol 2018; 84:AEM.00693-18. [PMID: 29728390 DOI: 10.1128/aem.00693-18] [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: 03/24/2018] [Accepted: 05/01/2018] [Indexed: 01/25/2023] Open
Abstract
Lysostaphin (Lst) is a potent bacteriolytic enzyme that kills Staphylococcus aureus, a common bacterial pathogen of humans and animals. With high activity against both planktonic cells and biofilms, Lst has the potential to be used in industrial products, such as commercial cleansers, for decontamination. However, Lst is inhibited in the presence of monoethanolamine (MEA), a chemical widely used in cleaning solutions and pharmaceuticals, and the underlying mechanism of inhibition remains unknown. In this study, we examined the cell binding and killing capabilities of Lst against S. aureus ATCC 6538 in buffered salt solution with MEA at different pH values (7.5 to 10.5) and discovered that only the unprotonated form of MEA inhibited Lst binding to the cell surface, leading to low Lst activity, despite retention of its secondary structure. This reduced enzyme activity could be largely recovered via a reduction in wall teichoic acid (WTA) biosynthesis through tunicamycin treatment, indicating that the suppression of Lst activity was dependent on the presence and amount of WTA. We propose that the decreased cell binding and killing capabilities of Lst are associated with the influence of uncharged MEA on the conformation of WTA. A similar effect was confirmed with other short-chain alkylamines. This study offers new insight into the impact of short-chain alkylamines on both Lst and WTA structure and function and provides guidance for the application of Lst in harsh environments.IMPORTANCE Lysostaphin (Lst) effectively and selectively kills Staphylococcus aureus, the bacterial culprit of many hospital- and community-acquired skin and respiratory infections and food poisoning. Lst has been investigated in animal models and clinical trials, industrial formulations, and environmental settings. Here, we studied the mechanistic basis of the inhibitory effect of alkylamines, such as monoethanolamine (MEA), a widely used chemical in commercial detergents, on Lst activity, for the potential incorporation of Lst in disinfectant solutions. We have found that protonated MEA has little influence on Lst activity, while unprotonated MEA prevents Lst from binding to S. aureus cells and hence dramatically decreases the enzyme's bacteriolytic efficacy. Following partial removal of the wall teichoic acid, an important component of the bacterial cell envelope, the inhibitory effect of unprotonated MEA on Lst is reduced. This phenomenon can be extended to other short-chain alkylamines. This mechanistic report of the impact of alkylamines on Lst functionality will help guide future applications of Lst in disinfection and decontamination of health-related commercial products.
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Exposure of Staphylococcus aureus to Targocil Blocks Translocation of the Major Autolysin Atl across the Membrane, Resulting in a Significant Decrease in Autolysis. Antimicrob Agents Chemother 2018; 62:AAC.00323-18. [PMID: 29735561 DOI: 10.1128/aac.00323-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/29/2018] [Indexed: 11/20/2022] Open
Abstract
Peptidoglycan (PG) and wall teichoic acid (WTA) are the major staphylococcal cell wall components, and WTA biosynthesis has recently been explored for drug development. Targocil is a novel agent that targets the TarG subunit of the WTA translocase (TarGH) that transports WTA across the membrane to the wall. Previously we showed that targocil treatment of a methicillin-susceptible Staphylococcus aureus strain led to a rapid shut down of cellular autolysis. Targocil II, which targets the TarH subunit of TarGH, also resulted in a drastic decrease in autolysis. Here, we address the mechanism of targocil-mediated decreased autolysis. The mechanism is WTA dependent since targocil treatment decreased autolysis in methicillin-resistant strains but not in a WTA-deficient mutant. Similar to cellular autolysis, autolysin-retaining crude cell walls isolated from targocil-treated cells had vastly decreased autolytic activity compared to those from untreated cells. Purified cell walls from control and targocil-treated cells, which lack autolytic activity, were similarly susceptible to lysozyme and lysostaphin and had similar O-acetyl contents, indicating that targocil treatment did not grossly alter PG structure and chemistry. Purified cell walls from targocil-treated cells were highly susceptible to autolysin extracts, supporting the notion that targocil treatment led to decreased autolysin in the crude cell walls. Quantitative real-time PCR analysis revealed that the decrease in autolysis in the targocil-exposed cells was not due to transcriptional repression of the autolysin genes atl, lytM, lytN, and sle1 Zymographic analysis of peptidoglycan hydrolase profiles showed a deficiency of cell surface autolysins in targocil-treated cells but higher activity in cell membrane fractions. Here, we propose that the untranslocated WTA molecules in the targocil-exposed cells sequester Atl at the membrane, resulting in significantly decreased autolysis.
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Salt-Induced Stress Stimulates a Lipoteichoic Acid-Specific Three-Component Glycosylation System in Staphylococcus aureus. J Bacteriol 2018; 200:JB.00017-18. [PMID: 29632092 DOI: 10.1128/jb.00017-18] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 04/03/2018] [Indexed: 01/01/2023] Open
Abstract
Lipoteichoic acid (LTA) in Staphylococcus aureus is a poly-glycerophosphate polymer anchored to the outer surface of the cell membrane. LTA has numerous roles in cell envelope physiology, including regulating cell autolysis, coordinating cell division, and adapting to environmental growth conditions. LTA is often further modified with substituents, including d-alanine and glycosyl groups, to alter cellular function. While the genetic determinants of d-alanylation have been largely defined, the route of LTA glycosylation and its role in cell envelope physiology have remained unknown, in part due to the low levels of basal LTA glycosylation in S. aureus We demonstrate here that S. aureus utilizes a membrane-associated three-component glycosylation system composed of an undecaprenol (Und) N-acetylglucosamine (GlcNAc) charging enzyme (CsbB; SAOUHSC_00713), a putative flippase to transport loaded substrate to the outside surface of the cell (GtcA; SAOUHSC_02722), and finally an LTA-specific glycosyltransferase that adds α-GlcNAc moieties to LTA (YfhO; SAOUHSC_01213). We demonstrate that this system is specific for LTA with no cross recognition of the structurally similar polyribitol phosphate containing wall teichoic acids. We show that while wild-type S. aureus LTA has only a trace of GlcNAcylated LTA under normal growth conditions, amounts are raised upon either overexpressing CsbB, reducing endogenous d-alanylation activity, expressing the cell envelope stress responsive alternative sigma factor SigB, or by exposure to environmental stress-inducing culture conditions, including growth media containing high levels of sodium chloride.IMPORTANCE The role of glycosylation in the structure and function of Staphylococcus aureus lipoteichoic acid (LTA) is largely unknown. By defining key components of the LTA three-component glycosylation pathway and uncovering stress-induced regulation by the alternative sigma factor SigB, the role of N-acetylglucosamine tailoring during adaptation to environmental stresses can now be elucidated. As the dlt and glycosylation pathways compete for the same sites on LTA and induction of glycosylation results in decreased d-alanylation, the interplay between the two modification systems holds implications for resistance to antibiotics and antimicrobial peptides.
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RgpF Is Required for Maintenance of Stress Tolerance and Virulence in Streptococcus mutans. J Bacteriol 2017; 199:JB.00497-17. [PMID: 28924033 DOI: 10.1128/jb.00497-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 09/12/2017] [Indexed: 02/01/2023] Open
Abstract
Bacterial cell wall dynamics have been implicated as important determinants of cellular physiology, stress tolerance, and virulence. In Streptococcus mutans, the cell wall is composed primarily of a rhamnose-glucose polysaccharide (RGP) linked to the peptidoglycan. Despite extensive studies describing its formation and composition, the potential roles for RGP in S. mutans biology have not been well investigated. The present study characterizes the impact of RGP disruption as a result of the deletion of rgpF, the gene encoding a rhamnosyltransferase involved in the construction of the core polyrhamnose backbone of RGP. The ΔrgpF mutant strain displayed an overall reduced fitness compared to the wild type, with heightened sensitivities to various stress-inducing culture conditions and an inability to tolerate acid challenge. The loss of rgpF caused a perturbation of membrane-associated functions known to be critical for aciduricity, a hallmark of S. mutans acid tolerance. The proton gradient across the membrane was disrupted, and the ΔrgpF mutant strain was unable to induce activity of the F1Fo ATPase in cultures grown under low-pH conditions. Further, the virulence potential of S. mutans was also drastically reduced following the deletion of rgpF The ΔrgpF mutant strain produced significantly less robust biofilms, indicating an impairment in its ability to adhere to hydroxyapatite surfaces. Additionally, the ΔrgpF mutant lost competitive fitness against oral peroxigenic streptococci, and it displayed significantly attenuated virulence in an in vivoGalleria mellonella infection model. Collectively, these results highlight a critical function of the RGP in the maintenance of overall stress tolerance and virulence traits in S. mutansIMPORTANCE The cell wall of Streptococcus mutans, the bacterium most commonly associated with tooth decay, is abundant in rhamnose-glucose polysaccharides (RGP). While these structures are antigenically distinct to S. mutans, the process by which they are formed and the enzymes leading to their construction are well conserved among streptococci. The present study describes the consequences of the loss of RgpF, a rhamnosyltransferase involved in RGP construction. The deletion of rgpF resulted in severe ablation of the organism's overall fitness, culminating in significantly attenuated virulence. Our data demonstrate an important link between the RGP and cell wall physiology of S. mutans, affecting critical features used by the organism to cause disease and providing a potential novel target for inhibiting the pathogenesis of S. mutans.
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Singh M, Chang J, Coffman L, Kim SJ. Hidden Mode of Action of Glycopeptide Antibiotics: Inhibition of Wall Teichoic Acid Biosynthesis. J Phys Chem B 2017; 121:3925-3932. [PMID: 28368603 DOI: 10.1021/acs.jpcb.7b00324] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Glycopeptide antibiotics inhibit the peptidoglycan biosynthesis in Gram-positive bacteria by targeting lipid II. This prevents the recycling of bactoprenol phosphate, the lipid transporter that is shared by peptidoglycan and wall teichoic acid biosyntheses. In this study, we investigate the effects of glycopeptide antibiotics on peptidoglycan and wall teichoic acid biosynthesis. The incorporation of d-[1-13C]alanine, d-[15N]alanine, and l-[1-13C]lysine into peptidoglycan and wall teichoic acid in intact whole cells of Staphylococcus aureus was measured using 13C{15N} and 15N{13C} rotational-echo double resonance NMR. S. aureus treated with oritavancin and vancomycin at subminimal inhibitory concentrations exhibit a large reduction in d-Ala incorporation into wall teichoic acid, but without changes to the peptidoglycan cross-links or the stem-links. Thus, sequestration of bactoprenol phosphate by glycopeptide antibiotics resulted in inhibition of d-Ala incorporation into the wall teichoic acid prior to the inhibition of peptidoglycan biosynthesis. Our finding shows that S. aureus responds to glycopeptide-induced cell wall stress by routing all available d-Ala to the peptidoglycan biosynthesis, at the cost of reducing the wall teichoic acid biosynthesis.
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Affiliation(s)
- Manmilan Singh
- Department of Chemistry, Washington University , St. Louis, Missouri 63130, United States
| | - James Chang
- Department of Chemistry and Biochemistry, Baylor University , Waco, Texas 76798, United States
| | - Lauryn Coffman
- Department of Chemistry and Biochemistry, Baylor University , Waco, Texas 76798, United States
| | - Sung Joon Kim
- Department of Chemistry and Biochemistry, Baylor University , Waco, Texas 76798, United States
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Quantitation of wall teichoic acid in Staphylococcus aureus by direct measurement of monomeric units using LC-MS/MS. Anal Biochem 2017; 518:9-15. [DOI: 10.1016/j.ab.2016.10.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 10/19/2016] [Accepted: 10/30/2016] [Indexed: 11/24/2022]
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Wanner S, Schade J, Keinhörster D, Weller N, George SE, Kull L, Bauer J, Grau T, Winstel V, Stoy H, Kretschmer D, Kolata J, Wolz C, Bröker BM, Weidenmaier C. Wall teichoic acids mediate increased virulence in Staphylococcus aureus. Nat Microbiol 2017; 2:16257. [DOI: 10.1038/nmicrobiol.2016.257] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 11/28/2016] [Indexed: 12/15/2022]
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37
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Matano LM, Morris HG, Wood BM, Meredith TC, Walker S. Accelerating the discovery of antibacterial compounds using pathway-directed whole cell screening. Bioorg Med Chem 2016; 24:6307-6314. [PMID: 27594549 PMCID: PMC5180449 DOI: 10.1016/j.bmc.2016.08.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 07/28/2016] [Accepted: 08/03/2016] [Indexed: 12/17/2022]
Abstract
Since the introduction of penicillin into the clinic in 1942, antibiotics have saved the lives of millions of people around the world. While penicillin and other traditional broad spectrum antibiotics were effective as monotherapies, the inexorable spread of antibiotic resistance has made alternative therapeutic approaches necessary. Compound combinations are increasingly seen as attractive options. Such combinations may include: lethal compounds; synthetically lethal compounds; or administering a lethal compound with a nonlethal compound that targets a virulence factor or a resistance factor. Regardless of the therapeutic strategy, high throughput screening is a key approach to discover potential leads. Unfortunately, the discovery of biologically active compounds that inhibit a desired pathway can be a very slow process, and an inordinate amount of time is often spent following up on compounds that do not have the desired biological activity. Here we describe a pathway-directed high throughput screening paradigm that combines the advantages of target-based and whole cell screens while minimizing the disadvantages. By exploiting this paradigm, it is possible to rapidly identify biologically active compounds that inhibit a pathway of interest. We describe some previous successful applications of this paradigm and report the discovery of a new class of d-alanylation inhibitors that may be useful as components of compound combinations to treat methicillin-resistant Staphylococcus aureus (MRSA).
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Affiliation(s)
- Leigh M Matano
- Department of Microbiology and Immunobiology, 4 Blackfan Circle, Boston, MA 02115, USA
| | - Heidi G Morris
- Department of Microbiology and Immunobiology, 4 Blackfan Circle, Boston, MA 02115, USA
| | - B McKay Wood
- Department of Microbiology and Immunobiology, 4 Blackfan Circle, Boston, MA 02115, USA
| | - Timothy C Meredith
- Department of Biochemistry and Molecular Biology, 206 South Frear Laboratory, University Park, PA 16802, USA.
| | - Suzanne Walker
- Department of Microbiology and Immunobiology, 4 Blackfan Circle, Boston, MA 02115, USA.
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38
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Sobhanifar S, Worrall LJ, King DT, Wasney GA, Baumann L, Gale RT, Nosella M, Brown ED, Withers SG, Strynadka NCJ. Structure and Mechanism of Staphylococcus aureus TarS, the Wall Teichoic Acid β-glycosyltransferase Involved in Methicillin Resistance. PLoS Pathog 2016; 12:e1006067. [PMID: 27973583 PMCID: PMC5156392 DOI: 10.1371/journal.ppat.1006067] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 11/15/2016] [Indexed: 01/05/2023] Open
Abstract
In recent years, there has been a growing interest in teichoic acids as targets for antibiotic drug design against major clinical pathogens such as Staphylococcus aureus, reflecting the disquieting increase in antibiotic resistance and the historical success of bacterial cell wall components as drug targets. It is now becoming clear that β-O-GlcNAcylation of S. aureus wall teichoic acids plays a major role in both pathogenicity and antibiotic resistance. Here we present the first structure of S. aureus TarS, the enzyme responsible for polyribitol phosphate β-O-GlcNAcylation. Using a divide and conquer strategy, we obtained crystal structures of various TarS constructs, mapping high resolution overlapping N-terminal and C-terminal structures onto a lower resolution full-length structure that resulted in a high resolution view of the entire enzyme. Using the N-terminal structure that encapsulates the catalytic domain, we furthermore captured several snapshots of TarS, including the native structure, the UDP-GlcNAc donor complex, and the UDP product complex. These structures along with structure-guided mutants allowed us to elucidate various catalytic features and identify key active site residues and catalytic loop rearrangements that provide a valuable platform for anti-MRSA drug design. We furthermore observed for the first time the presence of a trimerization domain composed of stacked carbohydrate binding modules, commonly observed in starch active enzymes, but adapted here for a poly sugar-phosphate glycosyltransferase. Historically, β-lactam class antibiotics such as methicillin have been very successful in the treatment of bacterial infections, effectively destroying bacteria by rupturing their cell walls while posing little harm to the human organism. In recent years, however, the alarming emergence of Methicillin Resistant S. aureus or MRSA has resulted in a world-wide health crisis, calling on new strategies to combat pathogenesis and antibiotic resistance. As such, understanding the pathways and players that orchestrate resistance is important for overcoming these mechanisms and restoring our powerful β-lactam antibiotic arsenal. In this article we describe the crystal structure of TarS, an enzyme responsible for the glycosylation of wall teichoic acid polymers of the S. aureus cell wall, a process that has been shown to be specifically responsible for methicillin resistance in MRSA. TarS is therefore a promising drug target whose inhibition in combinational therapies would result in MRSA re-sensitization to β-lactam antibiotics. Here we present the first structure of TarS together with several snap-shots of its substrate/product complexes, and elucidate important catalytic features that are valuable for rational drug design efforts to combat resistance in MRSA.
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Affiliation(s)
- Solmaz Sobhanifar
- Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, British Columbia, Canada
| | - Liam J. Worrall
- Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, British Columbia, Canada
| | - Dustin T. King
- Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gregory A. Wasney
- Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, British Columbia, Canada
| | - Lars Baumann
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Robert T. Gale
- Department of Chemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Michael Nosella
- Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, British Columbia, Canada
| | - Eric D. Brown
- Department of Chemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Stephen G. Withers
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Natalie C. J. Strynadka
- Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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39
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Lee SH, Wang H, Labroli M, Koseoglu S, Zuck P, Mayhood T, Gill C, Mann P, Sher X, Ha S, Yang SW, Mandal M, Yang C, Liang L, Tan Z, Tawa P, Hou Y, Kuvelkar R, DeVito K, Wen X, Xiao J, Batchlett M, Balibar CJ, Liu J, Xiao J, Murgolo N, Garlisi CG, Sheth PR, Flattery A, Su J, Tan C, Roemer T. TarO-specific inhibitors of wall teichoic acid biosynthesis restore β-lactam efficacy against methicillin-resistant staphylococci. Sci Transl Med 2016; 8:329ra32. [PMID: 26962156 DOI: 10.1126/scitranslmed.aad7364] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The widespread emergence of methicillin-resistant Staphylococcus aureus (MRSA) has dramatically eroded the efficacy of current β-lactam antibiotics and created an urgent need for new treatment options. We report an S. aureus phenotypic screening strategy involving chemical suppression of the growth inhibitory consequences of depleting late-stage wall teichoic acid biosynthesis. This enabled us to identify early-stage pathway-specific inhibitors of wall teichoic acid biosynthesis predicted to be chemically synergistic with β-lactams. We demonstrated by genetic and biochemical means that each of the new chemical series discovered, herein named tarocin A and tarocin B, inhibited the first step in wall teichoic acid biosynthesis (TarO). Tarocins do not have intrinsic bioactivity but rather demonstrated potent bactericidal synergy in combination with broad-spectrum β-lactam antibiotics against diverse clinical isolates of methicillin-resistant staphylococci as well as robust efficacy in a murine infection model of MRSA. Tarocins and other inhibitors of wall teichoic acid biosynthesis may provide a rational strategy to develop Gram-positive bactericidal β-lactam combination agents active against methicillin-resistant staphylococci.
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Affiliation(s)
- Sang Ho Lee
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Hao Wang
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Marc Labroli
- Merck Research Laboratories, West Point, PA 19486, USA
| | | | - Paul Zuck
- Merck Research Laboratories, West Point, PA 19486, USA
| | - Todd Mayhood
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Charles Gill
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Paul Mann
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Xinwei Sher
- Merck Research Laboratories, Boston, MA 02115, USA
| | - Sookhee Ha
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Shu-Wei Yang
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Mihir Mandal
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | | | - Lianzhu Liang
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Zheng Tan
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Paul Tawa
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Yan Hou
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | | | | | - Xiujuan Wen
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Jing Xiao
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | | | | | - Jenny Liu
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Jianying Xiao
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | | | | | - Payal R Sheth
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Amy Flattery
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Jing Su
- Merck Research Laboratories, Kenilworth, NJ 07033, USA.
| | | | - Terry Roemer
- Merck Research Laboratories, Kenilworth, NJ 07033, USA.
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40
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Dual Targeting of Cell Wall Precursors by Teixobactin Leads to Cell Lysis. Antimicrob Agents Chemother 2016; 60:6510-6517. [PMID: 27550357 DOI: 10.1128/aac.01050-16] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 08/06/2016] [Indexed: 01/29/2023] Open
Abstract
Teixobactin represents the first member of a newly discovered class of antibiotics that act through inhibition of cell wall synthesis. Teixobactin binds multiple bactoprenol-coupled cell wall precursors, inhibiting both peptidoglycan and teichoic acid synthesis. Here, we show that the impressive bactericidal activity of teixobactin is due to the synergistic inhibition of both targets, resulting in cell wall damage, delocalization of autolysins, and subsequent cell lysis. We also find that teixobactin does not bind mature peptidoglycan, further increasing its activity at high cell densities and against vancomycin-intermediate Staphylococcus aureus (VISA) isolates with thickened peptidoglycan layers. These findings add to the attractiveness of teixobactin as a potential therapeutic agent for the treatment of infection caused by antibiotic-resistant Gram-positive pathogens.
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41
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Wu X, Paskaleva EE, Mehta KK, Dordick JS, Kane RS. Wall Teichoic Acids Are Involved in the Medium-Induced Loss of Function of the Autolysin CD11 against Clostridium difficile. Sci Rep 2016; 6:35616. [PMID: 27759081 PMCID: PMC5069495 DOI: 10.1038/srep35616] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 09/23/2016] [Indexed: 01/05/2023] Open
Abstract
Bacterial lysins are potent antibacterial enzymes with potential applications in the treatment of bacterial infections. Some lysins lose activity in the growth media of target bacteria, and the underlying mechanism remains unclear. Here we use CD11, an autolysin of Clostridium difficile, as a model lysin to demonstrate that the inability of this enzyme to kill C. difficile in growth medium is not associated with inhibition of the enzyme activity by medium, or the modification of the cell wall peptidoglycan. Rather, wall teichoic acids (WTAs) appear to prevent the enzyme from binding to the cells and cleaving the cell wall peptidoglycan. By partially blocking the biosynthetic pathway of WTAs with tunicamycin, cell binding improved and the lytic efficacy of CD11 was significantly enhanced. This is the first report of the mechanism of lysin inactivation in growth medium, and provides insights into understanding the behavior of lysins in complex environments, including the gastrointestinal tract.
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Affiliation(s)
- Xia Wu
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, US.,Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, US
| | - Elena E Paskaleva
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, US
| | - Krunal K Mehta
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, US.,Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, US
| | - Jonathan S Dordick
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, US.,Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, US
| | - Ravi S Kane
- School of Chemical &Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, US
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42
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Schade J, Weidenmaier C. Cell wall glycopolymers of Firmicutes and their role as nonprotein adhesins. FEBS Lett 2016; 590:3758-3771. [PMID: 27396949 DOI: 10.1002/1873-3468.12288] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 06/27/2016] [Accepted: 07/05/2016] [Indexed: 12/12/2022]
Abstract
Cell wall glycopolymers (CWGs) of gram-positive bacteria have gained increasing interest with respect to their role in colonization and infection. In most gram-positive pathogens they constitute a large fraction of the cell wall biomass and represent major cell envelope determinants. Depending on their chemical structure they modulate interaction with complement factors and play roles in immune evasion or serve as nonprotein adhesins that mediate, especially under dynamic conditions, attachment to different host cell types. In particular, covalently peptidoglycan-attached CWGs that extend well above the cell wall seem to interact with glyco-receptors on host cell surfaces. For example, in the case of Staphylococcus aureus, the cell wall-attached teichoic acid (WTA) has been identified as a major CWG adhesin. A recent report indicates that a type-F scavenger receptor, termed SR-F1 (SREC-I), is the predominant WTA receptor in the nasal cavity and that WTA-SREC-I interaction plays an important role in S. aureus nasal colonization. Therefore, understanding the role of CWGs in complex processes that mediate colonization and infection will allow novel insights into the mechanisms of host-microbiota interaction.
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Affiliation(s)
- Jessica Schade
- Interfaculty Institute for Microbiology and Infection Medicine (IMIT), University of Tübingen, Germany
| | - Christopher Weidenmaier
- Interfaculty Institute for Microbiology and Infection Medicine (IMIT), University of Tübingen, Germany.,German Center for Infection Research (DZIF), Partnersite Tübingen, Germany
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43
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A toolbox to measure changes in the cell wall glycopolymer composition during differentiation of Streptomyces coelicolor A3(2). J Microbiol Methods 2016; 128:52-57. [PMID: 27401190 DOI: 10.1016/j.mimet.2016.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 07/01/2016] [Indexed: 02/06/2023]
Abstract
Cell wall glycopolymers (CWG) represent an important component of the Gram-positive cell envelope with many biological functions. The mycelial soil bacterium Streptomyces coelicolor A3(2) incorporates two distinct CWGs, polydiglycosylphosphate (PDP) and teichulosonic acid, into the cell wall of its vegetative mycelium but only little is known about their role in the complex life cycle of this microorganism. In this study we established assays to measure the total amount of CWGs in mycelial cell walls and spore walls, to quantify the individual CWGs and to determine the length of PDP. By applying these assays, we discovered that the relative amount of CWGs, especially of PDP, is reduced in spores compared to vegetative mycelium. Furthermore we found that PDP extracted from mycelial cell walls consisted of at least 19 repeating units, whereas spore walls contained substantially longer PDP polymers.
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44
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Romaniuk JAH, Cegelski L. Bacterial cell wall composition and the influence of antibiotics by cell-wall and whole-cell NMR. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2015.0024. [PMID: 26370936 DOI: 10.1098/rstb.2015.0024] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The ability to characterize bacterial cell-wall composition and structure is crucial to understanding the function of the bacterial cell wall, determining drug modes of action and developing new-generation therapeutics. Solid-state NMR has emerged as a powerful tool to quantify chemical composition and to map cell-wall architecture in bacteria and plants, even in the context of unperturbed intact whole cells. In this review, we discuss solid-state NMR approaches to define peptidoglycan composition and to characterize the modes of action of old and new antibiotics, focusing on examples in Staphylococcus aureus. We provide perspectives regarding the selected NMR strategies as we describe the exciting and still-developing cell-wall and whole-cell NMR toolkit. We also discuss specific discoveries regarding the modes of action of vancomycin analogues, including oritavancin, and briefly address the reconsideration of the killing action of β-lactam antibiotics. In such chemical genetics approaches, there is still much to be learned from perturbations enacted by cell-wall assembly inhibitors, and solid-state NMR approaches are poised to address questions of cell-wall composition and assembly in S. aureus and other organisms.
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Affiliation(s)
- Joseph A H Romaniuk
- Department of Chemistry, Stanford University, 380 Roth Way, Stanford, CA 94305, USA
| | - Lynette Cegelski
- Department of Chemistry, Stanford University, 380 Roth Way, Stanford, CA 94305, USA
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45
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Mann PA, Müller A, Wolff KA, Fischmann T, Wang H, Reed P, Hou Y, Li W, Müller CE, Xiao J, Murgolo N, Sher X, Mayhood T, Sheth PR, Mirza A, Labroli M, Xiao L, McCoy M, Gill CJ, Pinho MG, Schneider T, Roemer T. Chemical Genetic Analysis and Functional Characterization of Staphylococcal Wall Teichoic Acid 2-Epimerases Reveals Unconventional Antibiotic Drug Targets. PLoS Pathog 2016; 12:e1005585. [PMID: 27144276 PMCID: PMC4856313 DOI: 10.1371/journal.ppat.1005585] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 03/29/2016] [Indexed: 11/18/2022] Open
Abstract
Here we describe a chemical biology strategy performed in Staphylococcus aureus and Staphylococcus epidermidis to identify MnaA, a 2-epimerase that we demonstrate interconverts UDP-GlcNAc and UDP-ManNAc to modulate substrate levels of TarO and TarA wall teichoic acid (WTA) biosynthesis enzymes. Genetic inactivation of mnaA results in complete loss of WTA and dramatic in vitro β-lactam hypersensitivity in methicillin-resistant S. aureus (MRSA) and S. epidermidis (MRSE). Likewise, the β-lactam antibiotic imipenem exhibits restored bactericidal activity against mnaA mutants in vitro and concomitant efficacy against 2-epimerase defective strains in a mouse thigh model of MRSA and MRSE infection. Interestingly, whereas MnaA serves as the sole 2-epimerase required for WTA biosynthesis in S. epidermidis, MnaA and Cap5P provide compensatory WTA functional roles in S. aureus. We also demonstrate that MnaA and other enzymes of WTA biosynthesis are required for biofilm formation in MRSA and MRSE. We further determine the 1.9Å crystal structure of S. aureus MnaA and identify critical residues for enzymatic dimerization, stability, and substrate binding. Finally, the natural product antibiotic tunicamycin is shown to physically bind MnaA and Cap5P and inhibit 2-epimerase activity, demonstrating that it inhibits a previously unanticipated step in WTA biosynthesis. In summary, MnaA serves as a new Staphylococcal antibiotic target with cognate inhibitors predicted to possess dual therapeutic benefit: as combination agents to restore β-lactam efficacy against MRSA and MRSE and as non-bioactive prophylactic agents to prevent Staphylococcal biofilm formation. Staphylococcus aureus and Staphylococcus epidermidis cause life-threatening infections that are commonly acquired in hospitals as well as the community and remain difficult to treat with current antibiotics. In part, this is due to the emergence of methicillin-resistant S. aureus and S. epidermidis (MRSA and MRSE), which exhibit broad resistance to β-lactams such as penicillin and other members of this important founding class of antibiotics. Compounding this problem, Staphylococci commonly colonize the surface of catheters and other medical devices, forming bacterial communities that are intrinsically resistant to antibiotics. Here we functionally characterize a family of 2-epimerases, named MnaA and Cap5P, that we demonstrate by genetic, biochemical, and X-ray crystallography means are essential for wall teichoic acid biosynthesis and that upon their genetic inactivation render methicillin-resistant Staphylococci unable to form biofilms as well as broadly hypersusceptible to β-lactam antibiotics both in vitro and in a host infection setting. WTA 2-epimerases therefore constitute a novel class of methicillin-resistant Staphylococcal drug targets.
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Affiliation(s)
- Paul A. Mann
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Anna Müller
- Institute for Pharmaceutical Microbiology, University of Bonn, Bonn, Germany
- German Centre for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Kerstin A. Wolff
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Thierry Fischmann
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Hao Wang
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Patricia Reed
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Yan Hou
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Wenjin Li
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry, University of Bonn, Bonn, Germany
| | - Christa E. Müller
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry, University of Bonn, Bonn, Germany
| | - Jianying Xiao
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Nicholas Murgolo
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Xinwei Sher
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Todd Mayhood
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Payal R. Sheth
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Asra Mirza
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Marc Labroli
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Li Xiao
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Mark McCoy
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Charles J. Gill
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Mariana G. Pinho
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Tanja Schneider
- Institute for Pharmaceutical Microbiology, University of Bonn, Bonn, Germany
- German Centre for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Terry Roemer
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
- * E-mail:
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46
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Covas G, Vaz F, Henriques G, Pinho MG, Filipe SR. Analysis of Cell Wall Teichoic Acids in Staphylococcus aureus. Methods Mol Biol 2016; 1440:201-13. [PMID: 27311674 DOI: 10.1007/978-1-4939-3676-2_15] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Most bacterial cells are surrounded by a surface composed mainly of peptidoglycan (PGN), a glycopolymer responsible for ensuring the bacterial shape and a telltale molecule that betrays the presence of bacteria to the host immune system. In Staphylococcus aureus, as in most gram-positive bacteria, peptidoglycan is concealed by covalently linked molecules of wall teichoic acids (WTA)-phosphate rich molecules made of glycerol and ribitol phosphates which may be tailored by different amino acids and sugars.In order to analyze and compare the composition of WTA produced by different S. aureus strains, we describe methods to: (1) quantify the total amount of WTA present at the bacterial cell surface, through the determination of the inorganic phosphate present in phosphodiester linkages of WTA; (2) identify which sugar constituents are present in the assembled WTA molecules, by detecting the monosaccharides, released by acid hydrolysis, through an high-performance anion exchange chromatography analysis coupled with pulsed amperometric detection (HPAEC-PAD) and (3) compare the polymerization degree of WTA found at the cell surface of different S. aureus strains, through their different migration in a polyacrylamide gel electrophoresis (PAGE).
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Affiliation(s)
- Gonçalo Covas
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República, Apartado 127, 2781-901, Oeiras, Portugal
| | - Filipa Vaz
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República, Apartado 127, 2781-901, Oeiras, Portugal
| | - Gabriela Henriques
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Mariana G Pinho
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Sérgio R Filipe
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República, Apartado 127, 2781-901, Oeiras, Portugal. .,UCIBIO@REQUIMTE, Departamento de Ciências da Vida/ Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516, Caparica, Portugal.
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47
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Klahn P, Brönstrup M. New Structural Templates for Clinically Validated and Novel Targets in Antimicrobial Drug Research and Development. Curr Top Microbiol Immunol 2016; 398:365-417. [PMID: 27704270 DOI: 10.1007/82_2016_501] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The development of bacterial resistance against current antibiotic drugs necessitates a continuous renewal of the arsenal of efficacious drugs. This imperative has not been met by the output of antibiotic research and development of the past decades for various reasons, including the declining efforts of large pharma companies in this area. Moreover, the majority of novel antibiotics are chemical derivatives of existing structures that represent mostly step innovations, implying that the available chemical space may be exhausted. This review negates this impression by showcasing recent achievements in lead finding and optimization of antibiotics that have novel or unexplored chemical structures. Not surprisingly, many of the novel structural templates like teixobactins, lysocin, griselimycin, or the albicidin/cystobactamid pair were discovered from natural sources. Additional compounds were obtained from the screening of synthetic libraries and chemical synthesis, including the gyrase-inhibiting NTBI's and spiropyrimidinetrione, the tarocin and targocil inhibitors of wall teichoic acid synthesis, or the boronates and diazabicyclo[3.2.1]octane as novel β-lactamase inhibitors. A motif that is common to most clinically validated antibiotics is that they address hotspots in complex biosynthetic machineries, whose functioning is essential for the bacterial cell. Therefore, an introduction to the biological targets-cell wall synthesis, topoisomerases, the DNA sliding clamp, and membrane-bound electron transport-is given for each of the leads presented here.
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Affiliation(s)
- Philipp Klahn
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.
| | - Mark Brönstrup
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.
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Structure and mechanism of Staphylococcus aureus TarM, the wall teichoic acid α-glycosyltransferase. Proc Natl Acad Sci U S A 2015; 112:E576-85. [PMID: 25624472 DOI: 10.1073/pnas.1418084112] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Unique to Gram-positive bacteria, wall teichoic acids are anionic glycopolymers cross-stitched to a thick layer of peptidoglycan. The polyol phosphate subunits of these glycopolymers are decorated with GlcNAc sugars that are involved in phage binding, genetic exchange, host antibody response, resistance, and virulence. The search for the enzymes responsible for GlcNAcylation in Staphylococcus aureus has recently identified TarM and TarS with respective α- and β-(1-4) glycosyltransferase activities. The stereochemistry of the GlcNAc attachment is important in balancing biological processes, such that the interplay of TarM and TarS is likely important for bacterial pathogenicity and survival. Here we present the crystal structure of TarM in an unusual ternary-like complex consisting of a polymeric acceptor substrate analog, UDP from a hydrolyzed donor, and an α-glyceryl-GlcNAc product formed in situ. These structures support an internal nucleophilic substitution-like mechanism, lend new mechanistic insight into the glycosylation of glycopolymers, and reveal a trimerization domain with a likely role in acceptor substrate scaffolding.
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Weidenmaier C, Lee JC. Structure and Function of Surface Polysaccharides of Staphylococcus aureus. Curr Top Microbiol Immunol 2015; 409:57-93. [PMID: 26728067 DOI: 10.1007/82_2015_5018] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The major surface polysaccharides of Staphylococcus aureus include the capsular polysaccharide (CP), cell wall teichoic acid (WTA), and polysaccharide intercellular adhesin/poly-β(1-6)-N-acetylglucosamine (PIA/PNAG). These glycopolymers are important components of the staphylococcal cell envelope, but none of them is essential to S. aureus viability and growth in vitro. The overall biosynthetic pathways of CP, WTA, and PIA/PNAG have been elucidated, and the functions of most of the biosynthetic enzymes have been demonstrated. Because S. aureus CP and WTA (but not PIA/PNAG) utilize a common cell membrane lipid carrier (undecaprenyl-phosphate) that is shared by the peptidoglycan biosynthesis pathway, there is evidence that these processes are highly integrated and temporally regulated. Regulatory elements that control glycopolymer biosynthesis have been described, but the cross talk that orchestrates the biosynthetic pathways of these three polysaccharides remains largely elusive. CP, WTA, and PIA/PNAG each play distinct roles in S. aureus colonization and the pathogenesis of staphylococcal infection. However, they each promote bacterial evasion of the host immune defences, and WTA is being explored as a target for antimicrobial therapeutics. All the three glycopolymers are viable targets for immunotherapy, and each (conjugated to a carrier protein) is under evaluation for inclusion in a multivalent S. aureus vaccine. Future research findings that increase our understanding of these surface polysaccharides, how the bacterial cell regulates their expression, and their biological functions will likely reveal new approaches to controlling this important bacterial pathogen.
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Affiliation(s)
- Christopher Weidenmaier
- Interfaculty Institute for Microbiology and Infection Medicine Tübingen, University of Tübingen and German Center for Infection Research, Tübingen, Germany
| | - Jean C Lee
- Division of Infectious Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
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Abstract
Gram-positive organisms, including the pathogens Staphylococcus aureus, Streptococcus pneumoniae, and Enterococcus faecalis, have dynamic cell envelopes that mediate interactions with the environment and serve as the first line of defense against toxic molecules. Major components of the cell envelope include peptidoglycan (PG), which is a well-established target for antibiotics, teichoic acids (TAs), capsular polysaccharides (CPS), surface proteins, and phospholipids. These components can undergo modification to promote pathogenesis, decrease susceptibility to antibiotics and host immune defenses, and enhance survival in hostile environments. This chapter will cover the structure, biosynthesis, and important functions of major cell envelope components in gram-positive bacteria. Possible targets for new antimicrobials will be noted.
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