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Hu S, Zhang J, Jin Q. A formal aza-Michael addition and [4+3] annulation reactions of dichloro-substituted haloamides with N-(2-chloromethyl)aryl) amides. Tetrahedron Lett 2020. [DOI: 10.1016/j.tetlet.2020.152225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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2
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Miret-Casals L, Baelo A, Julián E, Astola J, Lobo-Ruiz A, Albericio F, Torrents E. Hydroxylamine Derivatives as a New Paradigm in the Search of Antibacterial Agents. ACS OMEGA 2018; 3:17057-17069. [PMID: 31458325 PMCID: PMC6643834 DOI: 10.1021/acsomega.8b01384] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 11/28/2018] [Indexed: 06/10/2023]
Abstract
Serious infections caused by bacteria that are resistant to commonly used antibiotics have become a major global healthcare problem in the 21st century. Multidrug-resistant bacteria causing severe infections mainly grow in complex bacterial communities known as biofilms, in which bacterial resistance to antibacterial agents and to the host immune system is strengthened. As drug resistance is becoming a threatening problem, it is necessary to develop new antimicrobial agents with novel mechanisms of action. Here, we designed and synthesized a small library of N-substituted hydroxylamine (N-HA) compounds with antibacterial activity. These compounds, acting as radical scavengers, inhibit the bacterial ribonucleotide reductase (RNR) enzyme. RNR enzyme is essential for bacterial proliferation during infection, as it provides the building blocks for DNA synthesis and repair. We demonstrate the broad antimicrobial effect of several drug candidates against a variety of Gram-positive and Gram-negative bacteria, together with low toxicity toward eukaryotic cells. Furthermore, the most promising compounds can reduce the biomass of an established biofilm on Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. This study settles the starting point to develop new N-hydroxylamine compounds as potential effective antibacterial agents to fight against drug-resistant pathogenic bacteria.
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Affiliation(s)
- Laia Miret-Casals
- Department
of Organic Chemistry, University of Barcelona, C/ Martí i Franquès,
1-11, 08028 Barcelona, Spain
| | - Aida Baelo
- Bacterial
Infections: Antimicrobial Therapies, Institute
for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac, 15-21, 08028 Barcelona, Spain
| | - Esther Julián
- Group
of Mycobacteriology, Department of Genetics
and Microbiology, Facultat de Biociències Universitat Autònoma de Barcelona, Building C, 08193 Bellaterra, Barcelona, Spain
| | - Josep Astola
- Bacterial
Infections: Antimicrobial Therapies, Institute
for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac, 15-21, 08028 Barcelona, Spain
| | - Ariadna Lobo-Ruiz
- Department
of Organic Chemistry, University of Barcelona, C/ Martí i Franquès,
1-11, 08028 Barcelona, Spain
| | - Fernando Albericio
- Department
of Organic Chemistry, University of Barcelona, C/ Martí i Franquès,
1-11, 08028 Barcelona, Spain
- CIBER-BBN,
Networking Centre on Bioengineering, Biomaterials and Nanomedicine, C/ Martí i Franquès,
1-11, 08028 Barcelona, Spain
- School
of Chemistry & Physics, University of
Kwazulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
| | - Eduard Torrents
- Bacterial
Infections: Antimicrobial Therapies, Institute
for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac, 15-21, 08028 Barcelona, Spain
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3
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Role of Ribonucleotide Reductase in Bacillus subtilis Stress-Associated Mutagenesis. J Bacteriol 2017; 199:JB.00715-16. [PMID: 27920297 DOI: 10.1128/jb.00715-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 11/29/2016] [Indexed: 01/21/2023] Open
Abstract
The Gram-positive microorganism Bacillus subtilis relies on a single class Ib ribonucleotide reductase (RNR) to generate 2'-deoxyribonucleotides (dNDPs) for DNA replication and repair. In this work, we investigated the influence of RNR levels on B. subtilis stationary-phase-associated mutagenesis (SPM). Since RNR is essential in this bacterium, we engineered a conditional mutant of strain B. subtilis YB955 (hisC952 metB5 leu427) in which expression of the nrdEF operon was modulated by isopropyl-β-d-thiogalactopyranoside (IPTG). Moreover, genetic inactivation of ytcG, predicted to encode a repressor (NrdR) of nrdEF in this strain, dramatically increased the expression levels of a transcriptional nrdE-lacZ fusion. The frequencies of mutations conferring amino acid prototrophy in three genes were measured in cultures under conditions that repressed or induced RNR-encoding genes. The results revealed that RNR was necessary for SPM and overexpression of nrdEF promoted growth-dependent mutagenesis and SPM. We also found that nrdEF expression was induced by H2O2 and such induction was dependent on the master regulator PerR. These observations strongly suggest that the metabolic conditions operating in starved B. subtilis cells increase the levels of RNR, which have a direct impact on SPM. IMPORTANCE Results presented in this study support the concept that the adverse metabolic conditions prevailing in nutritionally stressed bacteria activate an oxidative stress response that disturbs ribonucleotide reductase (RNR) levels. Such an alteration of RNR levels promotes mutagenic events that allow Bacillus subtilis to escape from growth-limited conditions.
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4
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Julián E, Baelo A, Gavaldà J, Torrents E. Methyl-hydroxylamine as an efficacious antibacterial agent that targets the ribonucleotide reductase enzyme. PLoS One 2015; 10:e0122049. [PMID: 25782003 PMCID: PMC4363900 DOI: 10.1371/journal.pone.0122049] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 02/06/2015] [Indexed: 01/17/2023] Open
Abstract
The emergence of multidrug-resistant bacteria has encouraged vigorous efforts to develop antimicrobial agents with new mechanisms of action. Ribonucleotide reductase (RNR) is a key enzyme in DNA replication that acts by converting ribonucleotides into the corresponding deoxyribonucleotides, which are the building blocks of DNA replication and repair. RNR has been extensively studied as an ideal target for DNA inhibition, and several drugs that are already available on the market are used for anticancer and antiviral activity. However, the high toxicity of these current drugs to eukaryotic cells does not permit their use as antibacterial agents. Here, we present a radical scavenger compound that inhibited bacterial RNR, and the compound's activity as an antibacterial agent together with its toxicity in eukaryotic cells were evaluated. First, the efficacy of N-methyl-hydroxylamine (M-HA) in inhibiting the growth of different Gram-positive and Gram-negative bacteria was demonstrated, and no effect on eukaryotic cells was observed. M-HA showed remarkable efficacy against Mycobacterium bovis BCG and Pseudomonas aeruginosa. Thus, given the M-HA activity against these two bacteria, our results showed that M-HA has intracellular antimycobacterial activity against BCG-infected macrophages, and it is efficacious in partially disassembling and inhibiting the further formation of P. aeruginosa biofilms. Furthermore, M-HA and ciprofloxacin showed a synergistic effect that caused a massive reduction in a P. aeruginosa biofilm. Overall, our results suggest the vast potential of M-HA as an antibacterial agent, which acts by specifically targeting a bacterial RNR enzyme.
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Affiliation(s)
- Esther Julián
- Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Aida Baelo
- Institute for Bioengineering of Catalonia (IBEC), Bacterial infections and antimicrobial therapies; Baldiri Reixac 15-21, Barcelona, Spain
| | - Joan Gavaldà
- Infectious Diseases Research Laboratory, Infectious Diseases Department, Vall d’Hebron Research Institute, Hospital Universitari Vall d'Hebron, Barcelona, Spain
| | - Eduard Torrents
- Institute for Bioengineering of Catalonia (IBEC), Bacterial infections and antimicrobial therapies; Baldiri Reixac 15-21, Barcelona, Spain
- * E-mail:
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5
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Munro JB, Jacob CG, Silva JC. A novel clade of unique eukaryotic ribonucleotide reductase R2 subunits is exclusive to apicomplexan parasites. J Mol Evol 2013; 77:92-106. [PMID: 24046025 PMCID: PMC3824934 DOI: 10.1007/s00239-013-9583-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 09/05/2013] [Indexed: 11/30/2022]
Abstract
Apicomplexa are protist parasites of tremendous medical and economic importance, causing millions of deaths and billions of dollars in losses each year. Apicomplexan-related diseases may be controlled via inhibition of essential enzymes. Ribonucleotide reductase (RNR) provides the only de novo means of synthesizing deoxyribonucleotides, essential precursors for DNA replication and repair. RNR has long been the target of antibacterial and antiviral therapeutics. However, targeting this ubiquitous protein in eukaryotic pathogens may be problematic unless these proteins differ significantly from that of their respective host. The typical eukaryotic RNR enzymes belong to class Ia, and the holoenzyme consists minimally of two R1 and two R2 subunits (α2β2). We generated a comparative, annotated, structure-based, multiple-sequence alignment of R2 subunits, identified a clade of R2 subunits unique to Apicomplexa, and determined its phylogenetic position. Our analyses revealed that the apicomplexan-specific sequences share characteristics with both class I R2 and R2lox proteins. The putative radical-harboring residue, essential for the reduction reaction by class Ia R2-containing holoenzymes, was not conserved within this group. Phylogenetic analyses suggest that class Ia subunits are not monophyletic and consistently placed the apicomplexan-specific clade sister to the remaining class Ia eukaryote R2 subunits. Our research suggests that the novel apicomplexan R2 subunit may be a promising candidate for chemotherapeutic-induced inhibition as it differs greatly from known eukaryotic host RNRs and may be specifically targeted.
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Affiliation(s)
- James B Munro
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
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6
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Cendra MDM, Juárez A, Torrents E. Biofilm modifies expression of ribonucleotide reductase genes in Escherichia coli. PLoS One 2012; 7:e46350. [PMID: 23050019 PMCID: PMC3458845 DOI: 10.1371/journal.pone.0046350] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 09/02/2012] [Indexed: 11/19/2022] Open
Abstract
Ribonucleotide reductase (RNR) is an essential enzyme for all living organisms since is the responsible for the last step in the synthesis of the four deoxyribonucleotides (dNTPs) necessary for DNA replication and repair. In this work, we have investigated the expression of the three-RNR classes (Ia, Ib and III) during Escherichia coli biofilm formation. We show the temporal and spatial importance of class Ib and III RNRs during this process in two different E. coli wild-type strains, the commensal MG1655 and the enteropathogenic and virulent E2348/69, the prototype for the enteropathogenic E. coli (EPEC). We have established that class Ib RNR, so far considered cryptic, play and important role during biofilm formation. The implication of this RNR class under the specific growth conditions of biofilm formation is discussed.
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Affiliation(s)
- Maria del Mar Cendra
- Cellular Biotechnology, Institute for Bioengineering of Catalonia (IBEC), Barcelona, Spain
| | - Antonio Juárez
- Cellular Biotechnology, Institute for Bioengineering of Catalonia (IBEC), Barcelona, Spain
- Department of Microbiology, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Eduard Torrents
- Cellular Biotechnology, Institute for Bioengineering of Catalonia (IBEC), Barcelona, Spain
- * E-mail:
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7
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Beierlein JM, Anderson AC. New developments in vaccines, inhibitors of anthrax toxins, and antibiotic therapeutics for Bacillus anthracis. Curr Med Chem 2012; 18:5083-94. [PMID: 22050756 DOI: 10.2174/092986711797636036] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 09/07/2011] [Accepted: 09/09/2011] [Indexed: 01/28/2023]
Abstract
Bacillus anthracis, the causative agent responsible for anthrax infections, poses a significant biodefense threat. There is a high mortality rate associated with untreated anthrax infections; specifically, inhalation anthrax is a particularly virulent form of infection with mortality rates close to 100%, even with aggressive treatment. Currently, a vaccine is not available to the general public and few antibiotics have been approved by the FDA for the treatment of inhalation anthrax. With the threat of natural or engineered bacterial resistance to antibiotics and the limited population for whom the current drugs are approved, there is a clear need for more effective treatments against this deadly infection. A comprehensive review of current research in drug discovery is presented in this article, including efforts to improve the purity and stability of vaccines, design inhibitors targeting the anthrax toxins, and identify inhibitors of novel enzyme targets. High resolution structural information for the anthrax toxins and several essential metabolic enzymes has played a significant role in aiding the structure-based design of potent and selective antibiotics.
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Affiliation(s)
- J M Beierlein
- Dept. Pharmaceutical Sciences, University of Connecticut, 69 N. Eagleville Rd., Storrs, CT 06269, USA
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8
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Crona M, Torrents E, Røhr AK, Hofer A, Furrer E, Tomter AB, Andersson KK, Sahlin M, Sjöberg BM. NrdH-redoxin protein mediates high enzyme activity in manganese-reconstituted ribonucleotide reductase from Bacillus anthracis. J Biol Chem 2011; 286:33053-60. [PMID: 21832039 PMCID: PMC3190916 DOI: 10.1074/jbc.m111.278119] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bacillus anthracis is a severe mammalian pathogen encoding a class Ib ribonucleotide reductase (RNR). RNR is a universal enzyme that provides the four essential deoxyribonucleotides needed for DNA replication and repair. Almost all Bacillus spp. encode both class Ib and class III RNR operons, but the B. anthracis class III operon was reported to encode a pseudogene, and conceivably class Ib RNR is necessary for spore germination and proliferation of B. anthracis upon infection. The class Ib RNR operon in B. anthracis encodes genes for the catalytic NrdE protein, the tyrosyl radical metalloprotein NrdF, and the flavodoxin protein NrdI. The tyrosyl radical in NrdF is stabilized by an adjacent Mn(2)(III) site (Mn-NrdF) formed by the action of the NrdI protein or by a Fe(2)(III) site (Fe-NrdF) formed spontaneously from Fe(2+) and O(2). In this study, we show that the properties of B. anthracis Mn-NrdF and Fe-NrdF are in general similar for interaction with NrdE and NrdI. Intriguingly, the enzyme activity of Mn-NrdF was approximately an order of magnitude higher than that of Fe-NrdF in the presence of the class Ib-specific physiological reductant NrdH, strongly suggesting that the Mn-NrdF form is important in the life cycle of B. anthracis. Whether the Fe-NrdF form only exists in vitro or whether the NrdF protein in B. anthracis is a true cambialistic enzyme that can work with either manganese or iron remains to be established.
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Affiliation(s)
- Mikael Crona
- Department of Molecular Biology and Functional Genomics, Arrhenius Laboratories for Natural Sciences, Stockholm University SE-10691 Stockholm, Sweden
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