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Antimicrobial Agents and Chemotherapy Nov 1992Aqueous solutions of 0.02% isoniazid, 0.2% streptomycin, 0.2% para-aminosalicylate, and 0.5% ethambutol and ethylene glycol solutions of 0.5% ethionamide stored at 3 to...
Aqueous solutions of 0.02% isoniazid, 0.2% streptomycin, 0.2% para-aminosalicylate, and 0.5% ethambutol and ethylene glycol solutions of 0.5% ethionamide stored at 3 to 7 degrees C remained stable for 1 year, as did aqueous solutions of 0.05% ethionamide hydrochloride, 0.05% kanamycin, 0.05% viomycin, and 0.1% capreomycin stored at -20 degrees C. The ethambutol and capreomycin solutions were tested by microbiologic methods; the other solutions were tested by both spectrophotometric and microbiologic methods. Prepared susceptibility testing media made with cycloserine, rifampin, and the above solutions incorporated into Middlebrook 7H10 medium showed acceptable stability when stored at 3 to 7 degrees C for 1 month. During incubation of the test medium at 37 degrees C, approximately half of the activity of isoniazid, ethionamide, ethambutol, cycloserine, and rifampin was lost after periods ranging from 2 to 4 days for ethambutol to 2 weeks for rifampin.
Topics: Antitubercular Agents; Chemistry, Pharmaceutical; Cold Temperature; Drug Stability; Drug Storage; Freezing; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Solutions; Temperature; Time Factors
PubMed: 1489183
DOI: 10.1128/AAC.36.11.2398 -
Journal of Biochemistry May 1978A new cross-linking reagent of the hetero-bisfunctional type, a N-(maleimidobenzoyloxy)-succinimide (MBS) was prepared and used for enzyme labelling of viomycin under...
A new cross-linking reagent of the hetero-bisfunctional type, a N-(maleimidobenzoyloxy)-succinimide (MBS) was prepared and used for enzyme labelling of viomycin under mild aqueous conditions by a two-step process. In the first step a maleimide residue was selectively introduced onto the N1-amino group of viomycin with a limited amount of MBS. The second step consisted of thioether formation between the maleimide residue and free thiol groups of beta-D-galactosidase. An antiserum to viomycin was raised in rabbit by immunization with a viomycin-BSA conjugate. The conjugate was prepared by protecting N6-amino group of viomycin with an acetyl group and succinylating the N1-amino group, activating the carboxyl group by a mixed anhydride method and coupling it with the amino groups of bovine serum albumin (BSA). The specificity of the antiserum was proved by an enzyme immunoassay based on the competition between viomycin and its enzyme conjugate toward diluted solutions of the antiserum. By use of the viomycin-enzyme conjugate and the antiserum to viomycin, enzyme immunoassay of viomycin was successfully performed by the competitive binding procedure with the double-antibody method, and 0.1 to 4 ng of the antibiotic could be detected.
Topics: Galactosidases; Immunoassay; Maleimides; Protein Binding; Succinimides; Viomycin
PubMed: 207686
DOI: 10.1093/oxfordjournals.jbchem.a132059 -
Antimicrobial Agents and Chemotherapy Oct 2011Capreomycin and the structurally similar compound viomycin are cyclic peptide antibiotics which are particularly active against Mycobacterium tuberculosis, including...
Capreomycin and the structurally similar compound viomycin are cyclic peptide antibiotics which are particularly active against Mycobacterium tuberculosis, including multidrug resistant strains. Both antibiotics bind across the ribosomal interface involving 23S rRNA helix 69 (H69) and 16S rRNA helix 44 (h44). The binding site of tuberactinomycins in h44 partially overlaps with that of aminoglycosides, and they share with these drugs the side effect of irreversible hearing loss. Here we studied the drug target interaction on ribosomes modified by site-directed mutagenesis. We identified rRNA residues in h44 as the main determinants of phylogenetic selectivity, predict compensatory evolution to impact future resistance development, and propose mechanisms involved in tuberactinomycin ototoxicity, which may enable the development of improved, less-toxic derivatives.
Topics: Aminoglycosides; Antitubercular Agents; Bacterial Proteins; Capreomycin; Drug Resistance, Multiple, Bacterial; Enviomycin; Mutagenesis, Site-Directed; Mycobacterium tuberculosis; RNA, Ribosomal, 16S; RNA, Ribosomal, 23S; Ribosomes; Viomycin
PubMed: 21768509
DOI: 10.1128/AAC.00628-11 -
Frontiers in Chemistry 2022CmnC is an α-ketoglutarate (α-KG)-dependent non-heme iron oxygenase involved in the formation of the l-capreomycidine (l-Cap) moiety in capreomycin (CMN) biosynthesis....
Crystal structure of the α-ketoglutarate-dependent non-heme iron oxygenase CmnC in capreomycin biosynthesis and its engineering to catalyze hydroxylation of the substrate enantiomer.
CmnC is an α-ketoglutarate (α-KG)-dependent non-heme iron oxygenase involved in the formation of the l-capreomycidine (l-Cap) moiety in capreomycin (CMN) biosynthesis. CmnC and its homologues, VioC in viomycin (VIO) biosynthesis and OrfP in streptothricin (STT) biosynthesis, catalyze hydroxylation of l-Arg to form β-hydroxy l-Arg (CmnC and VioC) or β,γ-dihydroxy l-Arg (OrfP). In this study, a combination of biochemical characterization and structural determination was performed to understand the substrate binding environment and substrate specificity of CmnC. Interestingly, despite having a high conservation of the substrate binding environment among CmnC, VioC, and OrfP, only OrfP can hydroxylate the substrate enantiomer d-Arg. Superposition of the structures of CmnC, VioC, and OrfP revealed a similar folds and overall structures. The active site residues of CmnC, VioC, and OrfP are almost conserved; however Leu136, Ser138, and Asp249 around the substrate binding pocket in CmnC are replaced by Gln, Gly, and Tyr in OrfP, respectively. These residues may play important roles for the substrate binding. The mutagenesis analysis revealed that the triple mutant CmnC switches the substrate stereoselectivity from l-Arg to d-Arg with ∼6% relative activity. The crystal structure of CmnC in complex with d-Arg revealed that the substrate loses partial interactions and adopts a different orientation in the binding site. This study provides insights into the enzyme engineering to α-KG non-heme iron oxygenases for adjustment to the substrate stereoselectivity and development of biocatalysts.
PubMed: 36176888
DOI: 10.3389/fchem.2022.1001311 -
Journal of Bacteriology Aug 1997We examined the molecular mechanisms of resistance to kanamycin and viomycin in Mycobacterium smegmatis. All of the M. smegmatis strains with high-level kanamycin...
We examined the molecular mechanisms of resistance to kanamycin and viomycin in Mycobacterium smegmatis. All of the M. smegmatis strains with high-level kanamycin resistance had a nucleotide substitution from A to G at position 1389 of the 16S rRNA gene (rrs). This position is equivalent to position 1408 of Escherichia coli, and mutation at this position is known to cause aminoglycoside resistance. Mutations from G to A or G to T at position 1473 of the M. smegmatis rrs gene were found in viomycin-resistant mutants which had been designated vicB mutants in our earlier studies. Using the M. smegmatis conjugation system, we confirmed that these mutations indeed contributed to kanamycin and viomycin resistance, and kanamycin susceptibility was dominant over resistance in a heterogenomic strain. Additional experiments showed that three of four Mycobacterium tuberculosis strains with high-level kanamycin resistance had a mutation from A to G at position 1400, which was equivalent to position 1389 of M. smegmatis.
Topics: Base Sequence; Capreomycin; Conjugation, Genetic; DNA, Bacterial; Drug Resistance, Microbial; Drug Resistance, Multiple; Genes, Dominant; Genes, Recessive; Genome, Bacterial; Kanamycin Resistance; Molecular Sequence Data; Mutation; Mycobacterium; Mycobacterium tuberculosis; RNA, Bacterial; RNA, Ribosomal, 16S; Sequence Analysis, RNA; Viomycin
PubMed: 9244267
DOI: 10.1128/jb.179.15.4795-4801.1997 -
Journal of Clinical Microbiology May 2010The aminoglycosides and cyclic polypeptides are essential drugs in the treatment of multidrug-resistant tuberculosis, underscoring the need for accurate and reproducible...
The aminoglycosides and cyclic polypeptides are essential drugs in the treatment of multidrug-resistant tuberculosis, underscoring the need for accurate and reproducible drug susceptibility testing (DST). The epidemiological cutoff value (ECOFF) separating wild-type susceptible strains from non-wild-type strains is an important but rarely used tool for indicating susceptibility breakpoints against Mycobacterium tuberculosis. In this study, we established wild-type MIC distributions on Middlebrook 7H10 medium for amikacin, kanamycin, streptomycin, capreomycin, and viomycin using 90 consecutive clinical isolates and 21 resistant strains. Overall, the MIC variation between and within runs did not exceed +/-1 MIC dilution step, and validation of MIC values in Bactec 960 MGIT demonstrated good agreement. Tentative ECOFFs defining the wild type were established for all investigated drugs, including amikacin and viomycin, which currently lack susceptibility breakpoints for 7H10. Five out of seven amikacin- and kanamycin-resistant isolates were classified as susceptible to capreomycin according to the current critical concentration (10 mg/liter) but were non-wild type according to the ECOFF (4 mg/liter), suggesting that the critical concentration may be too high. All amikacin- and kanamycin-resistant isolates were clearly below the ECOFF for viomycin, and two of them were below the ECOFF for streptomycin, indicating that these two drugs may be considered for treatment of amikacin-resistant strains. Pharmacodynamic indices (peak serum concentration [Cmax]/MIC) were more favorable for amikacin and viomycin compared to kanamycin and capreomycin. In conclusion, our data emphasize the importance of establishing wild-type MIC distributions for improving the quality of drug susceptibility testing against Mycobacterium tuberculosis.
Topics: Aminoglycosides; Antitubercular Agents; Culture Media; Humans; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Peptides, Cyclic; Tuberculosis
PubMed: 20237102
DOI: 10.1128/JCM.00240-10 -
Journal of Molecular Biology Jan 2015Previous structural studies suggested that ribosomal translocation is accompanied by large interdomain rearrangements of elongation factor G (EF-G). Here, we follow the...
Previous structural studies suggested that ribosomal translocation is accompanied by large interdomain rearrangements of elongation factor G (EF-G). Here, we follow the movement of domain IV of EF-G relative to domain II of EF-G using ensemble and single-molecule Förster resonance energy transfer. Our results indicate that ribosome-free EF-G predominantly adopts a compact conformation that can also, albeit infrequently, transition into a more extended conformation in which domain IV moves away from domain II. By contrast, ribosome-bound EF-G predominantly adopts an extended conformation regardless of whether it is interacting with pretranslocation ribosomes or with posttranslocation ribosomes. Our data suggest that ribosome-bound EF-G may also occasionally sample at least one more compact conformation. GTP hydrolysis catalyzed by EF-G does not affect the relative stability of the observed conformations in ribosome-free and ribosome-bound EF-G. Our data support a model suggesting that, upon binding to a pretranslocation ribosome, EF-G moves from a compact to a more extended conformation. This transition is not coupled to but likely precedes both GTP hydrolysis and mRNA/tRNA translocation.
Topics: Escherichia coli; Gene Rearrangement; Peptide Elongation Factor G; Protein Conformation; RNA, Messenger; RNA, Transfer; Ribosomes; Sequence Analysis, DNA; Translocation, Genetic
PubMed: 25463439
DOI: 10.1016/j.jmb.2014.11.010 -
FEBS Letters Jun 198370 S ribosomes were programmed with initiator tRNA and messenger oligonucleotides AUG(U)n and AUG(C)n, where n = 1, 2 or 3. The binding of the ternary complexes...
70 S ribosomes were programmed with initiator tRNA and messenger oligonucleotides AUG(U)n and AUG(C)n, where n = 1, 2 or 3. The binding of the ternary complexes [Phe-tRNA X EF-Tu X GTP] and [Pro-tRNA X EF-Tu X GTP] to the programmed ribosomes was studied. If codon-anticodon interaction is restricted to only one basepair, the ternary complex leaves the ribosome before GTP hydrolysis. Two basepairs allow hydrolysis of GTP, but the aminoacyl-tRNA dissociates and is recycled, resulting in wastage of GTP. Three basepairs result in apparently stable binding of aminoacyl-tRNA to the ribosome. The antibiotic sparsomycin weakens the binding by an amount roughly equivalent to one messenger base, while viomycin has the reverse effect.
Topics: Antibiotics, Antineoplastic; Binding Sites; Chemical Phenomena; Chemistry; Codon; Genetic Code; Guanosine Triphosphate; Hydrolysis; RNA, Messenger; RNA, Transfer, Amino Acyl; Ribosomes; Sparsomycin; Viomycin
PubMed: 6303858
DOI: 10.1016/0014-5793(83)80519-5 -
Journal of Natural Products Apr 2007The nonproteinogenic amino acid capreomycidine is the signature residue found in the tuberactinomycin family of antitubercular peptide antibiotics and an important...
The nonproteinogenic amino acid capreomycidine is the signature residue found in the tuberactinomycin family of antitubercular peptide antibiotics and an important element of the pharmacophore. Recombinant VioG, a single-module peptide synthetase from the viomycin gene cluster cloned from Streptomyces vinaceus (ATCC11861), specifically activates capreomycidine for incorporation into viomycin (tuberactinomycin B). Insertional disruption of the putative hydroxylase gene vioQ resulted in a mutant that accumulated tuberactinomycin O, suggesting that hydroxylation at C-5 of the capreomycidine residue is a post-assembly event. The inactivated chromosomal copy of vioQ could be complemented with a wild-type copy of the gene to restore viomycin production.
Topics: Anti-Bacterial Agents; Base Sequence; Escherichia coli; Genes, Bacterial; Molecular Structure; Peptide Synthases; Streptomyces; Viomycin
PubMed: 17302456
DOI: 10.1021/np060605u -
The Journal of Antibiotics Jul 1980An unidentified Streptomyces, designated as Strain H 1051-MY 10, was proved to produce viomycin and two new antibiotics. The new antibiotics were extracted from the...
An unidentified Streptomyces, designated as Strain H 1051-MY 10, was proved to produce viomycin and two new antibiotics. The new antibiotics were extracted from the cultured mycelia with acetone and transferred to ethyl acetate after acetone was removed in vacuo. The extracted antibiotics were separated into two components by alumina column chromatography and named carbazomycins A and B, because both antibiotics were proved to contain a carbazole nucleus. The molecular formulae of carbazomycins A and B were determined to be C16H17NO2 and C15H15NO2, respectively. Further, carbazomycin B was methylated with diazomethane to give carbazomycin A. Carbazomycins inhibited the growth of phytophathogenic fungi and further showed weak antibacterial and antiyeast activities.
Topics: Animals; Anti-Bacterial Agents; Bacteria; Carbazoles; Chemical Phenomena; Chemistry; Chemistry, Physical; Fermentation; Fungi; Mice; Streptomyces
PubMed: 7410212
DOI: 10.7164/antibiotics.33.683