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Koprivnjak T, Peschel A. Bacterial resistance mechanisms against host defense peptides. Cell Mol Life Sci 2011; 68:2243-54. [PMID: 21560069 PMCID: PMC11115334 DOI: 10.1007/s00018-011-0716-4] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 04/26/2011] [Accepted: 04/26/2011] [Indexed: 12/30/2022]
Abstract
Host defense peptides and proteins are important components of the innate host defense against pathogenic microorganisms. They target negatively charged bacterial surfaces and disrupt microbial cytoplasmic membranes, which ultimately leads to bacterial destruction. Throughout evolution, pathogens devised several mechanisms to protect themselves from deleterious damage of host defense peptides. These strategies include (a) inactivation and cleavage of host defense peptides by production of host defense binding proteins and proteases, (b) repulsion of the peptides by alteration of pathogen's surface charge employing modifications by amino acids or amino sugars of anionic molecules (e.g., teichoic acids, lipid A and phospholipids), (c) alteration of bacterial membrane fluidity, and (d) expulsion of the peptides using multi drug pumps. Together with bacterial regulatory network(s) that regulate expression and activity of these mechanisms, they represent attractive targets for development of novel antibacterials.
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Affiliation(s)
- Tomaz Koprivnjak
- Department of Biotechnology, National Institute of Chemistry Slovenia, Hajdrihova 19, 1000, Ljubljana, Slovenia,
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Staphylococcus aureus and Bacillus subtilis W23 make polyribitol wall teichoic acids using different enzymatic pathways. ACTA ACUST UNITED AC 2011; 17:1101-10. [PMID: 21035733 DOI: 10.1016/j.chembiol.2010.07.017] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Revised: 05/17/2010] [Accepted: 07/16/2010] [Indexed: 12/22/2022]
Abstract
Wall teichoic acids (WTAs) are anionic polymers that play key roles in bacterial cell shape, cell division, envelope integrity, biofilm formation, and pathogenesis. B. subtilis W23 and S. aureus both make polyribitol-phosphate (RboP) WTAs and contain similar sets of biosynthetic genes. We use in vitro reconstitution combined with genetics to show that the pathways for WTA biosynthesis in B. subtilis W23 and S. aureus are different. S. aureus requires a glycerol-phosphate primase called TarF in order to make RboP-WTAs; B. subtilis W23 contains a TarF homolog, but this enzyme makes glycerol-phosphate polymers and is not involved in RboP-WTA synthesis. Instead, B. subtilis TarK functions in place of TarF to prime the WTA intermediate for chain extension by TarL. This work highlights the enzymatic diversity of the poorly characterized family of phosphotransferases involved in WTA biosynthesis in Gram-positive organisms.
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54
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TelA contributes to the innate resistance of Listeria monocytogenes to nisin and other cell wall-acting antibiotics. Antimicrob Agents Chemother 2010; 54:4658-63. [PMID: 20713661 DOI: 10.1128/aac.00290-10] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Nisin is a class I bacteriocin (lantibiotic), which is employed by the food and veterinary industries and exhibits potent activity against numerous pathogens. However, this activity could be further improved through the targeting and inhibition of factors that contribute to innate nisin resistance. Here we describe a novel locus, lmo1967, which is required for optimal nisin resistance in Listeria monocytogenes. The importance of this locus, which is a homologue of the tellurite resistance gene telA, was revealed after the screening of a mariner random mutant bank of L. monocytogenes for nisin-susceptible mutants. The involvement of telA in nisin resistance was confirmed through an analysis of a nonpolar deletion mutant. In addition to being 4-fold-more susceptible to nisin, the ΔtelA strain was also 8-fold-more susceptible to gallidermin and 2-fold-more susceptible to cefuroxime, cefotaxime, bacitracin, and tellurite. This is the first occasion upon which telA has been investigated in a Gram-positive organism and also represents the first example of a link being established between a telA gene and resistance to cell envelope-acting antimicrobials.
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Homologs of aminoacyl-tRNA synthetases acylate carrier proteins and provide a link between ribosomal and nonribosomal peptide synthesis. Proc Natl Acad Sci U S A 2010; 107:14585-90. [PMID: 20663952 DOI: 10.1073/pnas.1007470107] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are ancient and evolutionary conserved enzymes catalyzing the formation of aminoacyl-tRNAs, that are used as substrates for ribosomal protein biosynthesis. In addition to full length aaRS genes, genomes of many organisms are sprinkled with truncated genes encoding single-domain aaRS-like proteins, which often have relinquished their canonical role in genetic code translation. We have identified the genes for putative seryl-tRNA synthetase homologs widespread in bacterial genomes and characterized three of them biochemically and structurally. The proteins encoded are homologous to the catalytic domain of highly diverged, atypical seryl-tRNA synthetases (aSerRSs) found only in methanogenic archaea and are deprived of the tRNA-binding domain. Remarkably, in comparison to SerRSs, aSerRS homologs display different and relaxed amino acid specificity. aSerRS homologs lack canonical tRNA aminoacylating activity and instead transfer activated amino acid to phosphopantetheine prosthetic group of putative carrier proteins, whose genes were identified in the genomic surroundings of aSerRS homologs. Detailed kinetic analysis confirmed that aSerRS homologs aminoacylate these carrier proteins efficiently and specifically. Accordingly, aSerRS homologs were renamed amino acid:[carrier protein] ligases (AMP forming). The enzymatic activity of aSerRS homologs is reminiscent of adenylation domains in nonribosomal peptide synthesis, and thus they represent an intriguing link between programmable ribosomal protein biosynthesis and template-independent nonribosomal peptide synthesis.
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56
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Lu X, Olsen SK, Capili AD, Cisar JS, Lima CD, Tan DS. Designed semisynthetic protein inhibitors of Ub/Ubl E1 activating enzymes. J Am Chem Soc 2010; 132:1748-9. [PMID: 20099854 DOI: 10.1021/ja9088549] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Semisynthetic, mechanism-based protein inhibitors of ubiquitin (Ub) and ubiquitin-like modifier (Ubl) activating enzymes (E1s) have been developed to target E1-catalyzed adenylation and thioesterification of the Ub/Ubl C-terminus during the processes of protein SUMOylation and ubiquitination. The inhibitors were generated by intein-mediated expressed protein ligation using a truncated Ub/Ubl protein (SUMO residues 1-94; Ub residues 1-71) with a C-terminal thioester and synthetic tripeptides having a C-terminal adenosine analogue and an N-terminal cysteine residue. SUMO-AMSN (4a) and Ub-AMSN (4b) contain a sulfamide group as a nonhydrolyzable mimic of the phosphate group in the cognate Ub/Ubl-AMP adenylate intermediate in the first half-reaction, and these constructs selectively inhibit SUMO E1 and Ub E1, respectively, in a dose-dependent manner. SUMO-AVSN (5a) and Ub-AVSN (5b) contain an electrophilic vinyl sulfonamide designed to trap the incoming E1 cysteine nucleophile (Uba2 Cys173 in SUMO E1; Uba1 Cys593 in Ub E1) in the second half-reaction, and these constructs selectively, covalently, and stably cross-link to SUMO E1 and Ub E1, respectively, in a cysteine nucleophile-dependent manner. These inhibitors are powerful tools to probe outstanding mechanistic questions in E1 function and can also be used to study the biological functions of E1 enzymes.
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Affiliation(s)
- Xuequan Lu
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, Box 422, New York, New York 10065, USA
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57
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Le Calvez PB, Scott CJ, Migaud ME. Multisubstrate adduct inhibitors: drug design and biological tools. J Enzyme Inhib Med Chem 2010; 24:1291-318. [PMID: 19912064 DOI: 10.3109/14756360902843809] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In drug discovery, different methods exist to create new inhibitors possessing satisfactory biological activity. The multisubstrate adduct inhibitor (MAI) approach is one of these methods, which consists of a covalent combination between analogs of the substrate and the cofactor or of the multiple substrates used by the target enzyme. Adopted as the first line of investigation for many enzymes, this method has brought insights into the enzymatic mechanism, structure, and inhibitory requirements. In this review, the MAI approach, applied to different classes of enzyme, is reported from the point of view of biological activity.
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58
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Swoboda JG, Campbell J, Meredith TC, Walker S. Wall teichoic acid function, biosynthesis, and inhibition. Chembiochem 2010; 11:35-45. [PMID: 19899094 DOI: 10.1002/cbic.200900557] [Citation(s) in RCA: 277] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Jonathan G Swoboda
- Department of Microbiology and Molecular Genetics, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA
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59
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Ernst CM, Staubitz P, Mishra NN, Yang SJ, Hornig G, Kalbacher H, Bayer AS, Kraus D, Peschel A. The bacterial defensin resistance protein MprF consists of separable domains for lipid lysinylation and antimicrobial peptide repulsion. PLoS Pathog 2009; 5:e1000660. [PMID: 19915718 PMCID: PMC2774229 DOI: 10.1371/journal.ppat.1000660] [Citation(s) in RCA: 239] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Accepted: 10/20/2009] [Indexed: 11/19/2022] Open
Abstract
Many bacterial pathogens achieve resistance to defensin-like cationic antimicrobial peptides (CAMPs) by the multiple peptide resistance factor (MprF) protein. MprF plays a crucial role in Staphylococcus aureus virulence and it is involved in resistance to the CAMP-like antibiotic daptomycin. MprF is a large membrane protein that modifies the anionic phospholipid phosphatidylglycerol with l-lysine, thereby diminishing the bacterial affinity for CAMPs. Its widespread occurrence recommends MprF as a target for novel antimicrobials, although the mode of action of MprF has remained incompletely understood. We demonstrate that the hydrophilic C-terminal domain and six of the fourteen proposed trans-membrane segments of MprF are sufficient for full-level lysyl-phosphatidylglycerol (Lys-PG) production and that several conserved amino acid positions in MprF are indispensable for Lys-PG production. Notably, Lys-PG production did not lead to efficient CAMP resistance and most of the Lys-PG remained in the inner leaflet of the cytoplasmic membrane when the large N-terminal hydrophobic domain of MprF was absent, indicating a crucial role of this protein part. The N-terminal domain alone did not confer CAMP resistance or repulsion of the cationic test protein cytochrome c. However, when the N-terminal domain was coexpressed with the Lys-PG synthase domain either in one protein or as two separate proteins, full-level CAMP resistance was achieved. Moreover, only coexpression of the two domains led to efficient Lys-PG translocation to the outer leaflet of the membrane and to full-level cytochrome c repulsion, indicating that the N-terminal domain facilitates the flipping of Lys-PG. Thus, MprF represents a new class of lipid-biosynthetic enzymes with two separable functional domains that synthesize Lys-PG and facilitate Lys-PG translocation. Our study unravels crucial details on the molecular basis of an important bacterial immune evasion mechanism and it may help to employ MprF as a target for new anti-virulence drugs.
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Affiliation(s)
- Christoph M. Ernst
- Cellular and Molecular Microbiology Division, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Petra Staubitz
- Cellular and Molecular Microbiology Division, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Nagendra N. Mishra
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor–University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America
| | - Soo-Jin Yang
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor–University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America
| | - Gabriele Hornig
- Cellular and Molecular Microbiology Division, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Hubert Kalbacher
- Medical and Natural Sciences Research Center, University of Tübingen, Tübingen, Germany
| | - Arnold S. Bayer
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor–University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America
- David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Dirk Kraus
- Cellular and Molecular Microbiology Division, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Andreas Peschel
- Cellular and Molecular Microbiology Division, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
- * E-mail:
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60
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Xia G, Kohler T, Peschel A. The wall teichoic acid and lipoteichoic acid polymers of Staphylococcus aureus. Int J Med Microbiol 2009; 300:148-54. [PMID: 19896895 DOI: 10.1016/j.ijmm.2009.10.001] [Citation(s) in RCA: 168] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Staphylococci and most other Gram-positive bacteria incorporate complex teichoic acid (TA) polymers into their cell envelopes. Several crucial roles in Staphylococcus aureus fitness and cell wall maintenance have been assigned to these polymers, which are either covalently linked to peptidoglycan (wall teichoic acid, WTA) or to the cytoplasmic membrane (lipoteichoic acid, LTA). However, the exact TA structures, functions, and biosynthetic pathways are only superficially understood. Recently, most of the enzymes mediating TA biosynthesis have been identified and mutants lacking or with defined changes in WTA or LTA have become available. Their characterization has revealed crucial roles of TAs in protection against harmful molecules and environmental stresses; in control of enzymes directing cell division or morphogenesis and of cation homeostasis; and in interaction with host or bacteriophage receptors and biomaterials. Accordingly, several in vivo studies have demonstrated the importance of WTA and LTA in S. aureus colonization, infection, and immune evasion. TAs and enzymes required for TA biosynthesis represent attractive candidates for novel vaccines and antibiotics and are targeted by recently developed antibacterial therapeutics.
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Affiliation(s)
- Guoqing Xia
- Division of Cellular and Molecular Microbiology, Institute of Medical Microbiology and Hygiene, University of Tübingen, Elfriede-Aulhorn-Strasse 6, D-72076 Tübingen, Germany
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61
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Swoboda JG, Meredith TC, Campbell J, Brown S, Suzuki T, Bollenbach T, Malhowski AJ, Kishony R, Gilmore MS, Walker S. Discovery of a small molecule that blocks wall teichoic acid biosynthesis in Staphylococcus aureus. ACS Chem Biol 2009; 4:875-83. [PMID: 19689117 DOI: 10.1021/cb900151k] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Both Gram-positive and Gram-negative bacteria contain bactoprenol-dependent biosynthetic pathways expressing non-essential cell surface polysaccharides that function as virulence factors. Although these polymers are not required for bacterial viability in vitro, genes in many of the biosynthetic pathways are conditionally essential: they cannot be deleted except in strains incapable of initiating polymer synthesis. We report a cell-based, pathway-specific strategy to screen for small molecule inhibitors of conditionally essential enzymes. The screen identifies molecules that prevent the growth of a wildtype bacterial strain but do not affect the growth of a mutant strain incapable of initiating polymer synthesis. We have applied this approach to discover inhibitors of wall teichoic acid (WTA) biosynthesis in Staphylococcus aureus. WTAs are anionic cell surface polysaccharides required for host colonization that have been suggested as targets for new antimicrobials. We have identified a small molecule, 7-chloro-N,N-diethyl-3-(phenylsulfonyl)-[1,2,3]triazolo[1,5-a]quinolin-5-amine (1835F03), that inhibits the growth of a panel of S. aureus strains (MIC = 1-3 microg mL(-1)), including clinical methicillin-resistant S. aureus (MRSA) isolates. Using a combination of biochemistry and genetics, we have identified the molecular target as TarG, the transmembrane component of the ABC transporter that exports WTAs to the cell surface. We also show that preventing the completion of WTA biosynthesis once it has been initiated triggers growth arrest. The discovery of 1835F03 validates our chemical genetics strategy for identifying inhibitors of conditionally essential enzymes, and the strategy should be applicable to many other bactoprenol-dependent biosynthetic pathways in the pursuit of novel antibacterials and probes of bacterial stress responses.
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Affiliation(s)
- Jonathan G. Swoboda
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115
| | - Timothy C. Meredith
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115
| | - Jennifer Campbell
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115
| | - Stephanie Brown
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115
| | - Takashi Suzuki
- The Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, 20 Staniford Street, Boston, Massachusetts 02114
| | - Tobias Bollenbach
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Amy J. Malhowski
- Department of Medicine, Tufts Medical Center, Boston, Massachusetts 02111
| | - Roy Kishony
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
| | - Michael S. Gilmore
- The Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, 20 Staniford Street, Boston, Massachusetts 02114
| | - Suzanne Walker
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115
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62
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Inactivation of DltA modulates virulence factor expression in Streptococcus pyogenes. PLoS One 2009; 4:e5366. [PMID: 19401780 PMCID: PMC2671602 DOI: 10.1371/journal.pone.0005366] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Accepted: 04/02/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND D-alanylated lipoteichoic acid is a virtually ubiquitous component of gram-positive cell walls. Mutations in the dltABCD operon of numerous species exhibit pleiotropic effects, including reduced virulence, which has been attributed to increased binding of cationic antimicrobial peptides to the more negatively charged cell surface. In this study, we have further investigated the effects that mutating dltA has on virulence factor expression in Streptococcus pyogenes. METHODOLOGY/PRINCIPAL FINDINGS Isogenic Delta dltA mutants had previously been created in two distinct M1T1 isolates of S. pyogenes. Immunoblots, flow cytometry, and immunofluorescence were used to quantitate M protein levels in these strains, as well as to assess their ability to bind complement. Bacteria were tested for their ability to interact with human PMN and to grow in whole human blood. Message levels for emm, sic, and various regulatory elements were assessed by quantitative RT-PCR. Cell walls of Delta dltA mutants contained much less M protein than cell walls of parent strains and this correlated with reduced levels of emm transcripts, increased deposition of complement, increased association of bacteria with polymorphonuclear leukocytes, and reduced bacterial growth in whole human blood. Transcription of at least one other gene of the mga regulon, sic, which encodes a protein that inactivates antimicrobial peptides, was also dramatically reduced in Delta dltA mutants. Concomitantly, ccpA and rofA were unaffected, while rgg and arcA were up-regulated. CONCLUSIONS/SIGNIFICANCE This study has identified a novel mechanism for the reduced virulence of dltA mutants of Streptococcus pyogenes in which gene regulatory networks somehow sense and respond to the loss of DltA and lack of D-alanine esterification of lipoteichoic acid. The mechanism remains to be determined, but the data indicate that the status of D-alanine-lipoteichoic acid can significantly influence the expression of at least some streptococcal virulence factors and provide further impetus to targeting the dlt operon of gram-positive pathogens in the search for novel antimicrobial compounds.
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63
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Osman KT, Du L, He Y, Luo Y. Crystal structure of Bacillus cereus D-alanyl carrier protein ligase (DltA) in complex with ATP. J Mol Biol 2009; 388:345-55. [PMID: 19324056 DOI: 10.1016/j.jmb.2009.03.040] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 03/05/2009] [Accepted: 03/13/2009] [Indexed: 11/29/2022]
Abstract
D-alanylation of lipoteichoic acids modulates the surface charge and ligand binding of the Gram-positive cell wall. Disruption of the bacterial dlt operon involved in teichoic acid alanylation, as well as inhibition of the DltA (D-alanyl carrier protein ligase) protein, has been shown to render the bacterium more susceptible to conventional antibiotics and host defense responses. The DltA catalyzes the adenylation and thiolation reactions of d-alanine. This enzyme belongs to a superfamily of AMP-forming domains such as the ubiquitous acetyl-coenzyme A synthetase. We have determined the 1.9-A-resolution crystal structure of a DltA protein from Bacillus cereus in complex with ATP. This structure sheds light on the geometry of the bound ATP. The invariant catalytic residue Lys492 appears to be mobile, suggesting a molecular mechanism of catalysis for this superfamily of enzymes. Specific roles are also revealed for two other invariant residues: the divalent cation-stabilizing Glu298 and the beta-phosphate-interacting Arg397. Mutant proteins with a glutamine substitution at position 298 or 397 are inactive.
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Affiliation(s)
- Khan Tanjid Osman
- Department of Biochemistry, University of Saskatchewan, A3 Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan, Canada S7N 5E5
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64
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Lu X, Zhang H, Tonge PJ, Tan DS. Mechanism-based inhibitors of MenE, an acyl-CoA synthetase involved in bacterial menaquinone biosynthesis. Bioorg Med Chem Lett 2008; 18:5963-6. [PMID: 18762421 PMCID: PMC2628629 DOI: 10.1016/j.bmcl.2008.07.130] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 07/28/2008] [Accepted: 07/29/2008] [Indexed: 11/22/2022]
Abstract
Menaquinone (vitamin K(2)) is an essential component of the electron transfer chain in many pathogens, including Mycobacterium tuberculosis and Staphylococcus aureus, and menaquinone biosynthesis is a potential target for antibiotic drug discovery. We report herein a series of mechanism-based inhibitors of MenE, an acyl-CoA synthetase that catalyzes adenylation and thioesterification of o-succinylbenzoic acid (OSB) during menaquinone biosynthesis. The most potent compound inhibits MenE with an IC(50) value of 5.7microM.
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Affiliation(s)
- Xuequan Lu
- Molecular Pharmacology & Chemistry Program and Tri-Institutional Research Program, Memorial Sloan–Kettering Cancer Center, New York, NY 10065, USA
| | - Huaning Zhang
- Institute of Chemical Biology & Drug Discovery, Department of Chemistry, Stony Brook University, Stony Brook, NY 11794, USA
| | - Peter J. Tonge
- Institute of Chemical Biology & Drug Discovery, Department of Chemistry, Stony Brook University, Stony Brook, NY 11794, USA
| | - Derek S. Tan
- Molecular Pharmacology & Chemistry Program and Tri-Institutional Research Program, Memorial Sloan–Kettering Cancer Center, New York, NY 10065, USA
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65
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Yonus H, Neumann P, Zimmermann S, May JJ, Marahiel MA, Stubbs MT. Crystal Structure of DltA. J Biol Chem 2008; 283:32484-91. [DOI: 10.1074/jbc.m800557200] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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66
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Du L, He Y, Luo Y. Crystal Structure and Enantiomer Selection by d-Alanyl Carrier Protein Ligase DltA from Bacillus cereus. Biochemistry 2008; 47:11473-80. [DOI: 10.1021/bi801363b] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Liqin Du
- Department of Biochemistry, University of Saskatchewan, A3 Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan, Canada S7N 5E5
| | - Yujiong He
- Department of Biochemistry, University of Saskatchewan, A3 Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan, Canada S7N 5E5
| | - Yu Luo
- Department of Biochemistry, University of Saskatchewan, A3 Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan, Canada S7N 5E5
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67
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Kraus D, Peschel A. Staphylococcus aureus evasion of innate antimicrobial defense. Future Microbiol 2008; 3:437-51. [PMID: 18651815 DOI: 10.2217/17460913.3.4.437] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Bacterial pathogens colonize human body surfaces soon after birth. In order to survive the constant threat of invasion and infection, the human innate immune system has evolved several efficient mechanisms to prevent harmful microorganisms from traversing epithelial barriers. These include cationic antimicrobial peptides (CAMPs) such as defensins and the cathelicidin LL-37, bacteriolytic enzymes such as lysozyme, antimicrobial fatty acids, toxic oxygen- or nitrogen-containing molecules, the bacteriolytic complement components and further mechanisms with indirect impacts on bacterial multiplication. Staphylococcus aureus is an important human commensal and pathogen. In order to successfully establish an infection, S. aureus has evolved several mechanisms to resist the innate immune system. In this review, we focus on the mechanisms employed by S. aureus to achieve protection against antimicrobial host defense molecules with special emphasis on CAMPs. Lessons from recent studies on antimicrobial host defense molecules and cognate bacterial resistance adaptation should help in the development of more sustainable anti-infective compounds.
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Affiliation(s)
- Dirk Kraus
- Cellular & Molecular Microbiology Division, Department of Medical Microbiology & Hygiene, University of Tübingen, Elfriede-Aulhorn-Strasse 6, 72076 Tübingen, Germany.
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68
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Antivirulence as a new antibacterial approach for chemotherapy. Curr Opin Chem Biol 2008; 12:400-8. [DOI: 10.1016/j.cbpa.2008.06.022] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Revised: 06/19/2008] [Accepted: 06/20/2008] [Indexed: 12/11/2022]
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69
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Cisar JS, Tan DS. Small molecule inhibition of microbial natural product biosynthesis-an emerging antibiotic strategy. Chem Soc Rev 2008; 37:1320-9. [PMID: 18568158 DOI: 10.1039/b702780j] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A variety of natural products modulate critical biological processes in the microorganisms that produce them. Thus, inhibition of the corresponding natural product biosynthesis pathways represents a promising avenue to develop novel antibiotics. In this tutorial review, we describe several recent examples of designed small molecule inhibitors of microbial natural product biosynthesis and their use in evaluating this emerging antibiotic strategy.
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Affiliation(s)
- Justin S Cisar
- Tri-Institutional Training Program in Chemical Biology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, Box 422, New York, NY 10065, USA
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70
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Teichoic acids and related cell-wall glycopolymers in Gram-positive physiology and host interactions. Nat Rev Microbiol 2008; 6:276-87. [PMID: 18327271 DOI: 10.1038/nrmicro1861] [Citation(s) in RCA: 539] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Most Gram-positive bacteria incorporate membrane- or peptidoglycan-attached carbohydrate-based polymers into their cell envelopes. Such cell-wall glycopolymers (CWGs) often have highly variable structures and have crucial roles in protecting, connecting and controlling the major envelope constituents. Further important roles of CWGs in host-cell adhesion, inflammation and immune activation have also been described in recent years. Identifying and harnessing highly conserved or species-specific structural features of CWGs offers excellent opportunities for developing new antibiotics, vaccines and diagnostics for use in the fight against severe infectious diseases, such as sepsis, pneumonia, anthrax and tuberculosis.
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71
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Stack D, Neville C, Doyle S. Nonribosomal peptide synthesis in Aspergillus fumigatus and other fungi. MICROBIOLOGY-SGM 2007; 153:1297-1306. [PMID: 17464044 DOI: 10.1099/mic.0.2006/006908-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In fungi, nonribosomal peptide synthetases (NRP synthetases) are large multi-functional enzymes containing adenylation, thiolation (or peptidyl carrier protein, PCP) and condensation domains. These enzymes are often encoded within gene clusters. Multiple NRP synthetase ORFs have also been identified in fungi (14 in Aspergillus fumigatus). LeaA, a methyltransferase, is involved in secondary metabolite gene cluster regulation in Aspergillus spp. The NRP synthetases GliP and FtmA respectively direct the biosynthesis of the toxic metabolites gliotoxin and brevianamide F, a precursor of bioactive prenylated alkaloids. The NRP synthetase Pes1 has been shown to mediate resistance to oxidative stress, and in plant-pathogenic ascomycetes (e.g. Cochliobolus heterostrophus) an NRP synthetase, encoded by the NPS6 gene, significantly contributes to virulence and resistance to oxidative stress. Adenylation (A) domains within NRP synthetases govern the specificity of amino acid incorporation into nonribosomally synthesized peptides. To date there have only been limited demonstrations of A domain specificity (e.g. A. fumigatus GliP and in Beauveria bassiana) in fungi. Indeed, only in silico prediction data are available on A domain specificity of NRP synthetases from most fungi. NRP synthetases are activated by 4'-phosphopantetheinylation of serine residues within PCP domains by 4'-phosphopantetheinyl transferases (4'-PPTases). Coenzyme A acts as the 4'-phosphopantetheine donor, and labelled coenzyme A can be used to affinity-label apo-NRP synthetases. Emerging fungal gene disruption and gene cluster expression strategies, allied to proteomic strategies, are poised to facilitate a greater understanding of the coding potential of NRP synthetases in fungi.
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Affiliation(s)
- Deirdre Stack
- Department of Biology and National Institute for Cellular Biotechnology, National University of Ireland, Maynooth, Co. Kildare, Ireland
| | - Claire Neville
- Department of Biology and National Institute for Cellular Biotechnology, National University of Ireland, Maynooth, Co. Kildare, Ireland
| | - Sean Doyle
- Department of Biology and National Institute for Cellular Biotechnology, National University of Ireland, Maynooth, Co. Kildare, Ireland
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72
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Abstract
High-affinity iron acquisition is mediated by siderophore-dependent pathways in the majority of pathogenic and nonpathogenic bacteria and fungi. Considerable progress has been made in characterizing and understanding mechanisms of siderophore synthesis, secretion, iron scavenging, and siderophore-delivered iron uptake and its release. The regulation of siderophore pathways reveals multilayer networks at the transcriptional and posttranscriptional levels. Due to the key role of many siderophores during virulence, coevolution led to sophisticated strategies of siderophore neutralization by mammals and (re)utilization by bacterial pathogens. Surprisingly, hosts also developed essential siderophore-based iron delivery and cell conversion pathways, which are of interest for diagnostic and therapeutic studies. In the last decades, natural and synthetic compounds have gained attention as potential therapeutics for iron-dependent treatment of infections and further diseases. Promising results for pathogen inhibition were obtained with various siderophore-antibiotic conjugates acting as "Trojan horse" toxins and siderophore pathway inhibitors. In this article, general aspects of siderophore-mediated iron acquisition, recent findings regarding iron-related pathogen-host interactions, and current strategies for iron-dependent pathogen control will be reviewed. Further concepts including the inhibition of novel siderophore pathway targets are discussed.
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Affiliation(s)
- Marcus Miethke
- Philipps Universität Marburg, FB Chemie Biochemie, Hans Meerwein Strasse, D-35032 Marburg, Germany
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73
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Cisar JS, Ferreras JA, Soni RK, Quadri LEN, Tan DS. Exploiting ligand conformation in selective inhibition of non-ribosomal peptide synthetase amino acid adenylation with designed macrocyclic small molecules. J Am Chem Soc 2007; 129:7752-3. [PMID: 17542590 PMCID: PMC2565600 DOI: 10.1021/ja0721521] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Justin S. Cisar
- Tri-Institutional Training Program in Chemical Biology, Tri-Institutional Research Program and Molecular Pharmacology & Chemistry Program, 1275 York Avenue, Box 422, New York, New York 10021
- Memorial Sloan–Kettering Cancer Center, 1275 York Avenue, Box 422, New York, New York 10021,
| | - Julian A. Ferreras
- Department of Microbiology & Immunology and Molecular Biology Program, Weill Medical College of Cornell University, 1300 York Avenue, Box 62, New York, New York 10021,
| | - Rajesh K. Soni
- Department of Microbiology & Immunology and Molecular Biology Program, Weill Medical College of Cornell University, 1300 York Avenue, Box 62, New York, New York 10021,
| | - Luis E. N. Quadri
- Tri-Institutional Training Program in Chemical Biology, Tri-Institutional Research Program and Molecular Pharmacology & Chemistry Program, 1275 York Avenue, Box 422, New York, New York 10021
- Department of Microbiology & Immunology and Molecular Biology Program, Weill Medical College of Cornell University, 1300 York Avenue, Box 62, New York, New York 10021,
| | - Derek S. Tan
- Tri-Institutional Training Program in Chemical Biology, Tri-Institutional Research Program and Molecular Pharmacology & Chemistry Program, 1275 York Avenue, Box 422, New York, New York 10021
- Memorial Sloan–Kettering Cancer Center, 1275 York Avenue, Box 422, New York, New York 10021,
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74
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Wright GD, Sutherland AD. New strategies for combating multidrug-resistant bacteria. Trends Mol Med 2007; 13:260-7. [PMID: 17493872 DOI: 10.1016/j.molmed.2007.04.004] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2007] [Revised: 04/03/2007] [Accepted: 04/30/2007] [Indexed: 11/24/2022]
Abstract
Antibiotic resistance is a problem that continues to challenge the healthcare sector. In particular, multidrug resistance is now common in familiar pathogens such as Staphylococcus aureus and Mycobacterium tuberculosis, as well as emerging pathogens such as Acinetobacter baumannii. New antibiotics and new therapeutic strategies are needed to address this challenge. Advances in identifying new sources of antibiotic natural products and expanding antibiotic chemical diversity are providing chemical leads for new drugs. Inhibitors of resistance mechanisms and microbial virulence are orthogonal strategies that are also generating new chemicals that can extend the life of existing antibiotics. This new chemistry, coupled with a growing understanding of the mechanisms, origins and distribution of antibiotic resistance, position us to tackle the challenges of antibiotic resistance in the 21st century.
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Affiliation(s)
- Gerard D Wright
- Antimicrobial Research Centre, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, McMaster University, 1200 Main St W, Hamilton, Ontario, L8N 3Z5, Canada.
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75
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Mercer AC, Burkart MD. The ubiquitous carrier protein--a window to metabolite biosynthesis. Nat Prod Rep 2007; 24:750-73. [PMID: 17653358 DOI: 10.1039/b603921a] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nature has developed a remarkable strategy to isolate metabolites from the milieu of the cell for chemical modification through the use of carrier proteins. Common to both primary and secondary metabolic pathways, acyl-carrier proteins constitute a conserved protein architecture which mediate the biosynthesis of a variety of metabolic products. Analogies have been made between the carrier protein and solid phase resin for chemical synthesis, as both entities provide a mechanism to separate compounds of interest from complex mixtures for selective chemical modification. However, there is significantly more to the carrier protein than an attachment point. In this review, we aim to systematically characterize the role of carrier proteins in various metabolic pathways and outline their utility in biosynthesis and biotechnology; 185 references are cited.
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Affiliation(s)
- Andrew C Mercer
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0358, USA
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76
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Linne U, Schäfer A, Stubbs MT, Marahiel MA. Aminoacyl-coenzyme A synthesis catalyzed by adenylation domains. FEBS Lett 2007; 581:905-10. [PMID: 17303131 DOI: 10.1016/j.febslet.2007.01.066] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Accepted: 01/25/2007] [Indexed: 11/29/2022]
Abstract
Adenylate forming enzymes play an important role in nature as they are involved in a number of essential biochemical pathways. In this study, we investigated the ability of a set of structurally related recombinant bacterial adenylate forming enzymes derived from nonribosomal peptide synthetases for their ability to synthesize acyl-CoAs in vitro. Adenylation-domains normally transfer their reactive aminoacyl-adenylates onto the covalently attached 4'-phosphopantetheine moiety of small carrier proteins. In detail, DltA, DhbE, GrsA-A, TycB(3)-A, and TycC(3)-A were investigated for their ability to synthesize acyl-CoAs. As reference, acetyl-CoA-synthetase (Acs) of B. subtilis was utilized, which naturally synthesizes acetyl-CoA from acetate, CoA-SH and ATP. Interestingly, all enzymes were capable of producing acyl-CoAs, albeit with differing efficiencies. Surprisingly, both CoA-SH and ATP were observed to inhibit the adenylation reaction at higher concentrations. Product quantification for kinetic determination was carried out by ESI-SIM-MS. Our results allow speculation as to evolutionary relationships within the large class of adenylate forming enzymes.
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Affiliation(s)
- Uwe Linne
- Philipps Universität Marburg, Fachbereich Chemie/Biochemie, Hans-Meerwein-Strasse, 35032 Marburg, Germany
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77
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Somu RV, Wilson DJ, Bennett EM, Boshoff HI, Celia L, Beck BJ, Barry CE, Aldrich CC. Antitubercular nucleosides that inhibit siderophore biosynthesis: SAR of the glycosyl domain. J Med Chem 2006; 49:7623-35. [PMID: 17181146 PMCID: PMC2526467 DOI: 10.1021/jm061068d] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Tuberculosis is the leading cause of infectious disease mortality in the world by a bacterial pathogen. We previously demonstrated that a bisubstrate inhibitor of the adenylation enzyme MbtA, which is responsible for the second step of mycobactin biosynthesis, exhibited potent antitubercular activity. Here we systematically investigate the structure-activity relationships of the bisubstrate inhibitor glycosyl domain resulting in the identification of a carbocyclic analogue that possesses a KIapp value of 2.3 nM and MIC99 values of 1.56 microM against M. tuberculosis H37Rv. The SAR data suggest the intriguing possibility that the bisubstrate inhibitors utilize a transporter for entry across the mycobacterial cell envelope. Additionally, we report improved conditions for the expression of MbtA and biochemical analysis, demonstrating that MbtA follows a random sequential enzyme mechanism for the adenylation half-reaction.
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Affiliation(s)
- Ravindranadh V Somu
- Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, MN 55455, USA
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78
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Miethke M, Bisseret P, Beckering CL, Vignard D, Eustache J, Marahiel MA. Inhibition of aryl acid adenylation domains involved in bacterial siderophore synthesis. FEBS J 2006; 273:409-19. [PMID: 16403027 DOI: 10.1111/j.1742-4658.2005.05077.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Aryl acid adenylation domains are the initial enzymes for aryl-capping of catecholic siderophores in a plethora of microorganisms. In order to overcome the problem of iron acquisition in host organisms, siderophore biosynthesis is decisive for virulence development in numerous important human and animal pathogens. Recently, it was shown that growth of Mycobacterium tuberculosis and Yersinia pestis can be inhibited in an iron-dependent manner using the arylic acyl adenylate analogue 5'-O-[N-(salicyl)-sulfamoyl] adenosine that acts on the salicylate activating domains, MbtA and YbtE [Ferreras JA, Ryu JS, Di Lello F, Tan DS, Quadri LEN (2005) Nat Chem Biol1, 29-32]. The present study explores the behaviour of the 2,3-dihydroxybenzoate activating domain DhbE (bacillibactin synthesis) and compares it to that of YbtE (yersiniabactin synthesis) upon enzymatic inhibition using a set of newly synthesized aryl sulfamoyl adenosine derivatives. The obtained results underline the highly specific mode of inhibition for both aryl acid activating domains in accordance with their natively accepted aryl moiety. These findings are discussed regarding the structure-function based aspect of aryl substrate binding to the DhbE and YbtE active sites.
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Affiliation(s)
- Marcus Miethke
- Philipps-Universität Marburg, Fachbereich Chemie/Biochemie, Marburg, Germany
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