101
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Bracchi-Ricard V, Nguyen KT, Zhou Y, Rajagopalan PT, Chakrabarti D, Pei D. Characterization of an eukaryotic peptide deformylase from Plasmodium falciparum. Arch Biochem Biophys 2001; 396:162-70. [PMID: 11747293 DOI: 10.1006/abbi.2001.2631] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ribosomal protein synthesis in eubacteria and eukaryotic organelles initiates with an N-formylmethionyl-tRNA(i), resulting in N-terminal formylation of all nascent polypeptides. Peptide deformylase (PDF) catalyzes the subsequent removal of the N-terminal formyl group from the majority of bacterial proteins. Until recently, PDF has been thought as an enzyme unique to the bacterial kingdom. Searches of the genomic DNA databases identified several genes that encode proteins of high sequence homology to bacterial PDF from eukaryotic organisms. The cDNA encoding Plasmodium falciparum PDF (PfPDF) has been cloned and overexpressed in Escherichia coli. The recombinant protein is catalytically active in deformylating N-formylated peptides, shares many of the properties of bacterial PDF, and is inhibited by specific PDF inhibitors. Western blot analysis indicated expression of mature PfPDF in trophozoite, schizont, and segmenter stages of intraerythrocytic development. These results provide strong evidence that a functional PDF is present in P. falciparum. In addition, PDF inhibitors inhibited the growth of P. falciparum in the intraerythrocytic culture.
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Affiliation(s)
- V Bracchi-Ricard
- Department of Molecular Biology & Microbiology, University of Central Florida, Orlando, FL 32816, USA
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102
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Abstract
There is an urgent need to develop new classes of antibiotics to tackle the increase in resistance in many common bacterial pathogens. One strategy to develop new antibiotics is to identify and exploit new molecular targets and this strategy is being driven by the wealth of new genome sequence information now available. Additionally, new technologies have been developed to validate new antibacterial targets, for example, new technologies have been developed to enable rapid determination of whether a gene is essential and to assess the transcription status of a putative target during infection. As a result, many novel validated targets have now been identified and for some, appropriate high-throughput screens against diverse compound collections have been carried out. Novel antibiotic leads are emerging from these genomics-derived targeted screens and the challenge now is to optimize and develop these leads to become part of the next generation of antibiotics.
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Affiliation(s)
- D McDevitt
- Antimicrobials and Host Defense CEDD, GlaxoSmithKline, Collegeville, PA 19426, USA.
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103
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Demirev PA, Lin JS, Pineda FJ, Fenselaut C. Bioinformatics and mass spectrometry for microorganism identification: proteome-wide post-translational modifications and database search algorithms for characterization of intact H. pylori. Anal Chem 2001; 73:4566-73. [PMID: 11605832 DOI: 10.1021/ac010466f] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
MALDI-TOF mass spectrometry has been coupled with Internet-based proteome database search algorithms in an approach for direct microorganism identification. This approach is applied here to characterize intact H. pylori (strain 26695) Gram-negative bacteria, the most ubiquitous human pathogen. A procedure for including a specific and common posttranslational modification, N-terminal Met cleavage, in the search algorithm is described. Accounting for posttranslational modifications in putative protein biomarkers improves the identification reliability by at least an order of magnitude. The influence of other factors, such as number of detected biomarker peaks, proteome size, spectral calibration, and mass accuracy, on the microorganism identification success rate is illustrated as well.
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Affiliation(s)
- P A Demirev
- Department of Chemistry, University of Maryland, College Park 20742, USA.
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104
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Forster AC, Weissbach H, Blacklow SC. A simplified reconstitution of mRNA-directed peptide synthesis: activity of the epsilon enhancer and an unnatural amino acid. Anal Biochem 2001; 297:60-70. [PMID: 11567528 DOI: 10.1006/abio.2001.5329] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The study of the early events in translation would be greatly facilitated by reconstitution with easily purified components. Here, Escherichia coli oligopeptide synthesis has been reconstituted using five purified recombinant His-tagged E. coli initiation and elongation factors. Highly purified ribosomes are required to yield products with strong dependencies on the translation factors. Based on HPLC separation of radiolabeled translation products from an mRNA encoding a tetrapeptide, approximately 80% of peptide products are full length, and the remaining 20% are the dipeptide and tripeptide products resulting from pausing or premature termination. Oligopeptide synthesis is enhanced when a commonly used epsilon (enhancer of protein synthesis initiation) sequence is included in the mRNA. The system incorporates a selectable, large, unnatural amino acid and may ultimately form the basis of a pure translation display technology for the directed evolution of peptidomimetic ligands and drug candidates. The recombinant clones can be exploited to prepare initiation factors and initiation complexes for structural studies, to study initiation and elongation in ribosomal peptide synthesis, and to screen for eubacterial-specific drugs.
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Affiliation(s)
- A C Forster
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, 75 Francis Street, Boston, Massachusetts 02115, USA.
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105
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St John G, Brot N, Ruan J, Erdjument-Bromage H, Tempst P, Weissbach H, Nathan C. Peptide methionine sulfoxide reductase from Escherichia coli and Mycobacterium tuberculosis protects bacteria against oxidative damage from reactive nitrogen intermediates. Proc Natl Acad Sci U S A 2001; 98:9901-6. [PMID: 11481433 PMCID: PMC55550 DOI: 10.1073/pnas.161295398] [Citation(s) in RCA: 159] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2001] [Indexed: 11/18/2022] Open
Abstract
Inducible nitric oxide synthase (iNOS) plays an important role in host defense. Macrophages expressing iNOS release the reactive nitrogen intermediates (RNI) nitrite and S-nitrosoglutathione (GSNO), which are bactericidal in vitro at a pH characteristic of the phagosome of activated macrophages. We sought to characterize the active intrabacterial forms of these RNI and their molecular targets. Peptide methionine sulfoxide reductase (MsrA; EC ) catalyzes the reduction of methionine sulfoxide (Met-O) in proteins to methionine (Met). E. coli lacking MsrA were hypersensitive to killing not only by hydrogen peroxide, but also by nitrite and GSNO. The wild-type phenotype was restored by transformation with plasmids encoding msrA from E. coli or M. tuberculosis, but not by an enzymatically inactive mutant msrA, indicating that Met oxidation was involved in the death of these cells. It seemed paradoxical that nitrite and GSNO kill bacteria by oxidizing Met residues when these RNI cannot themselves oxidize Met. However, under anaerobic conditions, neither nitrite nor GSNO was bactericidal. Nitrite and GSNO can both give rise to NO, which may react with superoxide produced by bacteria during aerobic metabolism, forming peroxynitrite, a known oxidant of Met to Met-O. Thus, the findings are consistent with the hypotheses that nitrite and GSNO kill E. coli by intracellular conversion to peroxynitrite, that intracellular Met residues in proteins constitute a critical target for peroxynitrite, and that MsrA can be essential for the repair of peroxynitrite-mediated intracellular damage.
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Affiliation(s)
- G St John
- Department of Microbiology and Immunology, Graduate Program in Immunology, Weill Medical College of Cornell University, New York, NY 10021, USA
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106
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Grant SK, Green BG, Kozarich JW. Inhibition and Structure-Activity Studies of Methionine Hydroxamic Acid Derivatives with Bacterial Peptide Deformylase. Bioorg Chem 2001; 29:211-22. [PMID: 16256693 DOI: 10.1006/bioo.2001.1214] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2001] [Indexed: 11/22/2022]
Abstract
The posttranslational deformylation of N-formyl-Met-polypeptides by the metalloenzyme, peptide deformylase, is essential for bacterial growth. Methionine hydroxamic acid derivatives were found to inhibit recombinant Escherichia coli peptide deformylase activity containing either zinc or cobalt. The binding of methionine hydroxamate and hydrazide inhibitors to cobalt-substituted deformylase caused spectral changes consistent with the formation of a pentacoordinate metal complex similar to that of actinonin, a psuedopeptide hydroxamate inhibitor. The spectral and kinetic data support the binding of these N-substituted L-methionine derivatives in a reverse orientation with respect to N-formyl-Met-peptide substrates within the active site. Based on this hypothesis a second generation of N-substituted methionyl hydroxamic acids were evaluated and found to possess greater inhibitory potency. These results may provide the basis for the design of more potent and selective deformylase inhibitors as potential antibacterial agents.
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Affiliation(s)
- S K Grant
- Department of HTS and Automation, Merck & Co., Rahway, New Jersey 07065, USA.
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107
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Apostol I, Brooks PD, Mathews AJ. Application of high-precision isotope ratio monitoring mass spectrometry to identify the biosynthetic origins of proteins. Protein Sci 2001; 10:1466-9. [PMID: 11420448 PMCID: PMC2374111 DOI: 10.1110/ps.90101] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Isotope ratio monitoring (IRM) mass spectrometry was used to measure the relative abundance of stable isotopes in several samples of adult human hemoglobin expressed in E. coli, yeast, and human blood. The results showed significant differences in the distribution of (15)N and (13)C isotopes among hemoglobin samples produced in these organisms. This indicates that IRM mass spectrometry can be used in forensic protein chemistry to identify the origin of protein expression.
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Affiliation(s)
- I Apostol
- Baxter Hemoglobin Therapeutics, Boulder, Colorado 80301, USA. iapostol@amgen
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108
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Haas M, Beyer D, Gahlmann R, Freiberg C. YkrB is the main peptide deformylase in Bacillus subtilis, a eubacterium containing two functional peptide deformylases. MICROBIOLOGY (READING, ENGLAND) 2001; 147:1783-1791. [PMID: 11429456 DOI: 10.1099/00221287-147-7-1783] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Peptide deformylation is an essential process in eubacteria. The peptide deformylase Def has been suggested to be an attractive target for antibacterial drug discovery. Some eubacteria including medically important pathogens possess two def-like genes. Until now, the functionality of both genes has been tested only in Staphylococcus aureus with the result that one gene copy was functional. Here, expression of two functional def-like gene products in Bacillus subtilis is demonstrated. Besides the def gene, which is chromosomally located close to the formyltransferase gene fmt and which was overexpressed and biochemically tested previously, B. subtilis possesses a second def-like gene, called ykrB. The encoded protein is 32% identical to the def gene product. It was shown that either def or ykrB had to be present for growth of B. subtilis in rich medium (each was individually dispensable). Studies with a def/ykrB double deletion strain with xylose-inducible ykrB copy demonstrated that, besides def, the gene ykrB is a second cellular target of deformylase inhibitors such as the antibiotic actinonin. The gene products exhibited similar enzymic properties, exemplified by similar inhibition efficacy of actinonin in biochemical assays. Antibiotic susceptibility tests with different deletion strains and Northern analyses indicated that YkrB is probably the predominant deformylase in B. subtilis. It was shown that duplication of the deformylase function does not lead to an increased actinonin-resistance frequency in comparison to B. subtilis mutants carrying only one deformylase gene.
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Affiliation(s)
- Michael Haas
- Institute for Anti-infectives Research, Pharma Research, Bayer AG, D-42096 Wuppertal, Germany1
| | - Dieter Beyer
- Institute for Anti-infectives Research, Pharma Research, Bayer AG, D-42096 Wuppertal, Germany1
| | - Reinhold Gahlmann
- Institute for Anti-infectives Research, Pharma Research, Bayer AG, D-42096 Wuppertal, Germany1
| | - Christoph Freiberg
- Institute for Anti-infectives Research, Pharma Research, Bayer AG, D-42096 Wuppertal, Germany1
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109
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Apfel CM, Evers S, Hubschwerlen C, Pirson W, Page MG, Keck W. Peptide deformylase as an antibacterial drug target: assays for detection of its inhibition in Escherichia coli cell homogenates and intact cells. Antimicrob Agents Chemother 2001; 45:1053-7. [PMID: 11257015 PMCID: PMC90424 DOI: 10.1128/aac.45.4.1053-1057.2001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An assay was developed to determine the activity of peptide deformylase (PDF) inhibitors under conditions as close as possible to the physiological situation. The assay principle is the detection of N-terminal [35S]methionine labeling of a protein that contains no internal methionine. If PDF is active, the deformylation of the methionine renders the peptide a substrate for methionine aminopeptidase, resulting in the removal of the N-terminal methionine label. In the presence of a PDF inhibitor, the deformylation is blocked so that the N-formylated peptide is not processed and the label is detected. Using this assay, it is possible to determine the PDF activity under near-physiological conditions in a cell-free transcription-translation system as well as in intact bacterial cells.
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Affiliation(s)
- C M Apfel
- Pharma Research Basel, F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland.
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110
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Apfel CM, Locher H, Evers S, Takács B, Hubschwerlen C, Pirson W, Page MG, Keck W. Peptide deformylase as an antibacterial drug target: target validation and resistance development. Antimicrob Agents Chemother 2001; 45:1058-64. [PMID: 11257016 PMCID: PMC90425 DOI: 10.1128/aac.45.4.1058-1064.2001] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
New inhibitors of peptide deformylase (PDF) which are very potent against the isolated enzyme and show a certain degree of antibacterial activity have recently been synthesized by our group. Several lines of experimental evidence indicate that these inhibitors indeed interfere with the target enzyme in the bacterial cell. (i) The inhibition of Escherichia coli growth could be counteracted by overexpression of PDF from different organisms, including E. coli, Streptococcus pneumoniae, and Haemophilus influenzae. Conversely, reduced expression of PDF in S. pneumoniae resulted in an increased susceptibility to the inhibitors. (ii) Proteome analysis on two-dimensional gels revealed a shift for many proteins towards lower pI in the presence of PDF inhibitors, as would be expected if the proteins still carry their N-formyl-Met terminus. (iii) PDF inhibitors show no antimicrobial activity against E. coli under conditions that make growth independent of formylation and deformylation. The antibacterial activity in E. coli was characterized as bacteriostatic. Furthermore, the development of resistance in E. coli was observed to occur with high frequency (10(-7)). Resistant mutants show a reduced growth rate, and DNA sequence analysis revealed mutations in their formyl transferase gene. Taking all these aspects into account, we conclude that PDF may not be an optimal target for broad-spectrum antibacterial agents.
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Affiliation(s)
- C M Apfel
- Pharma Research Basel, F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland.
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111
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Clements JM, Beckett RP, Brown A, Catlin G, Lobell M, Palan S, Thomas W, Whittaker M, Wood S, Salama S, Baker PJ, Rodgers HF, Barynin V, Rice DW, Hunter MG. Antibiotic activity and characterization of BB-3497, a novel peptide deformylase inhibitor. Antimicrob Agents Chemother 2001; 45:563-70. [PMID: 11158755 PMCID: PMC90327 DOI: 10.1128/aac.45.2.563-570.2001] [Citation(s) in RCA: 165] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Peptide deformylase (PDF) is an essential bacterial metalloenzyme which deformylates the N-formylmethionine of newly synthesized polypeptides and as such represents a novel target for antibacterial chemotherapy. To identify novel PDF inhibitors, we screened a metalloenzyme inhibitor library and identified an N-formyl-hydroxylamine derivative, BB-3497, and a related natural hydroxamic acid antibiotic, actinonin, as potent and selective inhibitors of PDF. To elucidate the interactions that contribute to the binding affinity of these inhibitors, we determined the crystal structures of BB-3497 and actinonin bound to Escherichia coli PDF at resolutions of 2.1 and 1.75 A, respectively. In both complexes, the active-site metal atom was pentacoordinated by the side chains of Cys 90, His 132, and His 136 and the two oxygen atoms of N-formyl-hydroxylamine or hydroxamate. BB-3497 had activity against gram-positive bacteria, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis, and activity against some gram-negative bacteria. Time-kill analysis showed that the mode of action of BB-3497 was primarily bacteriostatic. The mechanism of resistance was via mutations within the formyltransferase gene, as previously described for actinonin. While actinonin and its derivatives have not been used clinically because of their poor pharmacokinetic properties, BB-3497 was shown to be orally bioavailable. A single oral dose of BB-3497 given 1 h after intraperitoneal injection of S. aureus Smith or methicillin-resistant S. aureus protected mice from infection with median effective doses of 8 and 14 mg/kg of body weight, respectively. These data validate PDF as a novel target for the design of a new generation of antibacterial agents.
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Affiliation(s)
- J M Clements
- British Biotech Pharmaceuticals Ltd., Oxford OX4 6LY, United Kingdom.
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112
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Metzler DE, Metzler CM, Sauke DJ. Ribosomes and the Synthesis of Proteins. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50032-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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113
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Giglione C, Pierre M, Meinnel T. Peptide deformylase as a target for new generation, broad spectrum antimicrobial agents. Mol Microbiol 2000; 36:1197-205. [PMID: 10931273 DOI: 10.1046/j.1365-2958.2000.01908.x] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Peptide deformylase was discovered 30 years ago, but as a result of its unusually unstable activity it was not fully characterized until very recently. The aim of this paper is to review the many recent data concerning this enzyme and to try to assess its potential as a target for future antimicrobial drugs.
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Affiliation(s)
- C Giglione
- Institut des Sciences Végétales, UPR40, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France
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114
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Sekowska A, Coppée JY, Le Caer JP, Martin-Verstraete I, Danchin A. S-adenosylmethionine decarboxylase of Bacillus subtilis is closely related to archaebacterial counterparts. Mol Microbiol 2000; 36:1135-47. [PMID: 10844697 DOI: 10.1046/j.1365-2958.2000.01930.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Bacillus subtilis synthesizes polyamines by decarboxylating arginine to agmatine, which is subsequently hydrolysed to putrescine. Spermidine is synthesized from putrescine and decarboxylated S-adenosylmethionine (dAdoMet). In Gram-negative bacteria and in eukaryotes, AdoMet is decarboxylated by an unusual 'pyruvoyl' AdoMet decarboxylase (SpeD), the catalytic pyruvoyl moiety of which is generated by serinolysis of an internal serine with self-cleavage of the protein at the upstream peptide bond. Neither the Gram-positive bacterial nor the archaeal counterpart of the Escherichia coli SpeD enzyme were known. We have identified the corresponding B. subtilis speD gene (formely ytcF). Heterologous expression of the cognate Methanococcus jannaschii protein, MJ0315, demonstrated that it displays the same activity as B. subtilis SpeD, indicating that spermidine biosynthesis in Gram-positive bacteria and in archaea follows a pathway very similar to that of Gram-negatives and eukarya. In B. subtilis, transcription of speD is modulated by spermidine and methionine. Its expression is high under usual growth conditions. In contrast, the SpeD protein self-cleaves slowly in vitro, a noticeable difference with its archaeal counterpart. Under certain growth conditions (minimal medium containing succinate and glutamate as a carbon source), speD is co-transcribed with gapB, the gene encoding glyceraldehyde-3-phosphate dehydrogenase, an enzyme required for gluconeogenesis. This observation may couple polyamine metabolism to sulphur and carbon metabolism by a so far unknown mechanism.
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Affiliation(s)
- A Sekowska
- Régulation de l'Expression Génétique, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris, France
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