Mechanism of action of cinodine, a glycocinnamoylspermidine antibiotic

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Cinodine, a broad-spectrum glycocinnamoylspermidine antibiotic, binds to DNA and irreversibly inhibits bacterial and phage DNA synthesis. Cinodine was found to inhibit the activity of Micrococcus luteus DNA gyrase in vitro, but it did not inhibit the activities of two other DNA-binding enzymes, namely, topoisomerase I and BamHI. Although we cannot yet conclude that DNA gyrase is an intracellular target of the drug, in vitro inhibition of the enzyme by cinodine appears to be specific.Bacterial topoisomerase II (DNA gyrase) is an essential enzyme that is known to be the target of two classes of antibiotics. The coumarins, natural products which include coumermycin Al and novobiocin, inhibit gyrase probably by competing with ATP for binding to the B subunit of the enzyme (6, 11). The quinolones, synthetic products typified by nalidixic and oxolinic acids, target the A subunit of the enzyme and probably act by interfering with the DNArejoining step of the gyrase-mediated, DNA strand-passing reaction (1, 4, 5, 12; for recent reviews of topoisomerase inhibitors, see references 2 and 13).The broad-spectrum antibiotic cinodine, which is produced by a Nocardia species (3, 9), represents a class of antibiotics referred to as the glycocinnamoylspermidines.The three components of cinodine, ,B, -Yl, and Y2, are distinguished by the structure of the terminal pentose of the trisaccharide (Fig. 1). In previous studies of its mechanism of action (7), cinodine was shown to cause an immediate and irreversible cessation of DNA synthesis in growing cultures of Escherichia coli, whereas RNA synthesis remained unaffected for at least 30 min. Furthermore, equilibrium dialysis studies showed that cinodine was able to bind physically to DNA (7). In the present study, we investigated the mechanism of action of cinodine further, and we found that the drug inhibits bacterial DNA gyrase in vitro.DNA gyrase activity of Micrococcus luteus is inhibited by cinodine. The conversion of relaxed plasmid pBR322 DNA to the supercoiled form by M. luteus DNA gyrase was tested in the presence and absence of cinodine. Purified DNA gyrase from M. luteus was obtained from Bethesda Research Laboratories, Inc., Gaithersburg, Md. DNA gyrase was assayed in vitro for the ability to convert relaxed covalently closed circular DNA to the supercoiled form in the presence of ATP by the standard electrophoretic assay method of Otter and Cozzarelli (10). The relaxed substrate (0.5 ,ug of plasmid pBR322) was prepared by treating supercoiled plasmid DNA with topoisomerase I isolated from calf thymus (Bethesda Research Laboratories), according to the directions of the manufacturer, followed by three phenol-chloroform extractions (to remove the enzyme) and ethanol precipitation of the DNA. Gyrase assays were carried out in a total volume of 20 ,ul. Enzyme (1 U) was added to the assay mixture as the last step, to initiate the reaction; the mixture was then incubated at 30°C for 1 h and applied directly to a 0.8% agarose gel. Samples were electrophoresed at 150 * Correspondi...

“…2A and B). This effect is consistent with the previous demonstration that cinodine physically binds to DNA (7).…”

supporting

confidence: 82%

mentioning

confidence: 86%

In vitro inhibition of bacterial DNA gyrase by cinodine, a glycocinnamoylspermidine antibiotic

Osburne¹,

Maiese²,

Greenstein³

1990

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“…The P-lactam antibiotics demonstrating strong affinities for PBP 3 are known to produce long filaments in E. coli (6). Inhibitors of DNA synthesis, such as ciprofloxacin and cinodine, indirectly inhibit cell division by inducing the SOS response and produce filaments (4,12,20). The filamentation induced by bioxalomycin a2 in E. coli (shorter filaments) is consistent with a DNA-damaging mode of action.…”

Section: Discussionmentioning

confidence: 66%

Mechanistic studies and biological activity of bioxalomycin alpha 2, a novel antibiotic produced by Streptomyces viridodiastaticus subsp. "litoralis" LL-31F508

Singh¹,

Petersen²,

Jacobus³

et al. 1994

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The bioxalomycins, a novel complex of broad-spectrum antibiotics, were isolated from fermentations of Streptomyces viridodiastaticus subsp. "litoralis" LL-31F508. Bioxalomycin ax2, the major component of this complex, exhibited antibacterial activity. The MICs ranged from s0.002 to 0.008 ,uglml for gram-positive organisms and from 0.50 to 4 ,ug/ml for gram-negative organisms. Bioxalomycin a2 was found to be bactericidal and to inhibit bacterial DNA synthesis preferentially. Bioxalomycin a2 protected mice from a lethal challenge with Staphylococcus aureus Smith. The 50% effective dose of bioxalomycin a2 administered orally was 10 times greater than that when the drug was given subcutaneously or intravenously. These data suggest a stability or bioavailability problem when the compound is administered orally.The evolution and spread of antibiotic-resistant pathogens remain major clinical problems (15). Although the discovery of new antimicrobial agents has become increasingly more difficult, the search for unique metabolites from microorganisms remains an attractive venture (2, 13).

“…Squalamine (from dogfish shark) and cinodine (from Nocardia spp.) are natural antibiotics with a polyamine backbone in their structures (35,36). The role of polyamine conjugation in improving activity for a number of synthetic antibacterial agents, such as ceragenins, acylpolyamines, and caffeoyl polyamines, has been reported (15,33,37).…”

Section: Discussionmentioning

confidence: 99%

N-Terminally Modified Linear and Branched Spermine Backbone Dipeptidomimetics against Planktonic and Sessile Methicillin-Resistant Staphylococcus aureus

Dewangan

Joshi

Kumari

et al. 2014

c Toward the discovery of useful therapeutic molecules, we report the design and synthesis of a focused library of new ultrashort N-terminally modified dipeptidomimetics, with or without modifications in the spermine backbone leading to linear (series 1) or branched (series 2) tryptophans, as antimicrobial agents. Eight peptidomimetics in the library showed good antibacterial activity (MICs of 1.77 to 14.2 g/ml) against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis bacterial strains. Tryptophan fluorescence measurements on artificial bacterial or mammalian mimic membranes and assessment of the MRSA potential depolarization ability of the designed compounds revealed membrane interactions dependent on tryptophan positioning and N-terminal tagging. Among active peptidomimetics, compounds 1c and 1d were found to be nonhemolytic, displaying rapid bactericidal activity (at 4؋ MIC) against exponentially growing MRSA. Further, scanning electron microscopy of peptidomimetic 1c-and 1d-treated MRSA showed morphological changes with damage to cell walls, defining a membrane-active mode of action. Moreover, peptidomimetics 1c and 1d did not induce significant drug resistance in MRSA even after 17 passages. We also investigated the activity of these molecules against MRSA biofilms. At sub-MIC levels (ϳ2 to 4 g/ml), both peptidomimetics inhibited biofilm formation. At concentrations higher than the MIC (35 to 140 g/ml), peptidomimetics 1c and 1d significantly reduced the metabolic activity and biomass of mature (24-h) MRSA biofilms. These results were corroborated by confocal laser scanning microscopy (live/dead assay). The in vitro protease stability and lower cytotoxicity of peptidomimetics against peripheral blood mononuclear cells (PBMCs) support them being novel staphylocidal peptidomimetics. In conclusion, this study provides two peptidomimetics as potential leads for treatment of staphylococcal infections under planktonic and sessile conditions.