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Journal of Bacteriology Sep 2001Oleandomycin, a macrolide antibiotic produced by Streptomyces antibioticus, contains two sugars attached to the aglycon: L-oleandrose and D-desosamine. oleY codes for a...
Oleandomycin, a macrolide antibiotic produced by Streptomyces antibioticus, contains two sugars attached to the aglycon: L-oleandrose and D-desosamine. oleY codes for a methyltransferase involved in the biosynthesis of L-oleandrose. This gene was overexpressed in Escherichia coli to form inclusion bodies and in Streptomyces lividans, producing a soluble protein. S. lividans overexpressing oleY was used as a biotransformation host, and it converted the precursor L-olivosyl-erythronolide B into its 3-O-methylated derivative, L-oleandrosyl-erythronolide B. Two other monoglycosylated derivatives were also substrates for the OleY methyltransferase: L-rhamnosyl- and L-mycarosyl-erythronolide B. OleY methyltransferase was purified yielding a 43-kDa single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The native enzyme showed a molecular mass of 87 kDa by gel filtration chromatography, indicating that the enzyme acts as a dimer. It showed a narrow pH range for optimal activity, and its activity was clearly stimulated by the presence of several divalent cations, being maximal with Co(2+). The S. antibioticus OleG2 glycosyltransferase is proposed to transfer L-olivose to the oleandolide aglycon, which is then converted into L-oleandrose by the OleY methyltransferase. This represents an alternative route for L-oleandrose biosynthesis from that in the avermectin producer Streptomyces avermitilis, in which L-oleandrose is transferred to the aglycon by a glycosyltransferase.
Topics: Anti-Bacterial Agents; Deoxy Sugars; Escherichia coli; Hexoses; Methyltransferases; Oleandomycin; Streptomyces; Streptomyces antibioticus; Substrate Specificity
PubMed: 11514520
DOI: 10.1128/JB.183.18.5358-5363.2001 -
Antimicrobial Agents and Chemotherapy Sep 1973STUDIES ON ERYTHROMYCIN RESISTANCE IN STRAINS OF GROUP A STREPTOCOCCI INDICATED THAT THEY WERE COMPRISED OF TWO TYPES: (i) an inducible, resistant type (IR strains) was...
STUDIES ON ERYTHROMYCIN RESISTANCE IN STRAINS OF GROUP A STREPTOCOCCI INDICATED THAT THEY WERE COMPRISED OF TWO TYPES: (i) an inducible, resistant type (IR strains) was seen, which manifested immediate logarithmic growth in media containing high concentrations of the drug only after brief previous exposure (induction period) of the organisms to subinhibitory concentrations of erythromycin, and (ii) a constitutive, resistant type (CR strains) which demonstrated, without prior drug exposure, continued logarithmic growth in media containing high concentrations of erythromycin. Subinhibitory concentrations of either chloramphenicol or puromycin, when added to IR strains prior to induction, interfered with their induction by erythromycin. Exposure of CR strains to chloramphenicol did not visibly affect the subsequent growth curve of these strains in media containing high concentrations of erythromycin. In IR strains, resistance to other macrolide antibiotics (oleandomycin, spiramycin, carbomycin, magnamycin) and to lincomycin also was inducible in nature. There was cross-inducibility between erythromycin, other macrolide antibiotics, and lincomycin. CR strains were constitutively resistant to these antibiotics.
Topics: Anti-Bacterial Agents; Chloramphenicol; Culture Media; Densitometry; Drug Resistance, Microbial; Erythromycin; Leucomycins; Lincomycin; Methods; Microbial Sensitivity Tests; Oleandomycin; Puromycin; Streptococcus pyogenes; Time Factors
PubMed: 4586147
DOI: 10.1128/AAC.4.3.327 -
Antimicrobial Agents and Chemotherapy Aug 1999Macrolide 2'-phosphotransferase [MPH(2')] transfers the gamma phosphate of ATP to the 2'-OH group of macrolide antibiotics. The role of aspartic acids in the putative...
Macrolide 2'-phosphotransferase [MPH(2')] transfers the gamma phosphate of ATP to the 2'-OH group of macrolide antibiotics. The role of aspartic acids in the putative ATP-binding site of MPH(2')II was investigated through the substitution of alanine for aspartate by site-directed mutagenesis. D200A, D209A, D219A, and D231A mutant strains were unable to inactivate the substrate oleandomycin, while a D227A mutant retained 7% of the activity of the original enzyme.
Topics: Adenosine Triphosphate; Alanine; Amino Acid Sequence; Anti-Bacterial Agents; Aspartic Acid; Binding Sites; Drug Resistance, Microbial; Escherichia coli; Escherichia coli Proteins; Molecular Sequence Data; Mutagenesis, Site-Directed; Oleandomycin; Phosphotransferases (Alcohol Group Acceptor); Sequence Homology, Amino Acid; Substrate Specificity
PubMed: 10428938
DOI: 10.1128/AAC.43.8.2063 -
British Journal of Pharmacology May 19961. The effects of 7-ethoxyresorufin (7-ER), which is a substrate for and competitive inhibitor of cytochrome P450, were studied on responses to nitric oxide (NO), the NO...
1. The effects of 7-ethoxyresorufin (7-ER), which is a substrate for and competitive inhibitor of cytochrome P450, were studied on responses to nitric oxide (NO), the NO donors sodium nitroprusside (SNP) and glyceryl trinitrate (GTN), acetylcholine-induced endothelium-dependent relaxations of rat and rabbit aortic rings and nitrergic nerve stimulation-induced relaxations of rat anococcygeus muscles. 2. In rat and rabbit aortic rings, 7-ER (2 microM) inhibited the relaxations to acetylcholine in endothelium-intact preparations and the relaxant action of NO in endothelium-denuded preparations. Relaxant responses to SNP and GTN were inhibited by 7-ER in the rat but not rabbit aortic rings. However, the relaxant actions of papaverine and 8-bromo-cyclic GMP were not affected by 7-ER. 3. In rat anococcygeus muscles, 7ER (2 microM) inhibited the relaxant action of NO, but relaxations elicited by nitrergic nerve stimulation were only partly inhibited by a higher concentration of 7-ER (10 microM). 4. After inhibition by 7-ER, superoxide dismutase (100 u ml-1) restored NO-induced relaxations of the rat aortic rings, but not acetylcholine-, SNP or GTN-induced relaxations, and restored NO- and nitrergic nerve stimulation-induced relaxations of anococcygeus muscles. 5. Another cytochrome P450 inhibitor, troleandomycin (10-30 microM), had no effect on NO- or acetylcholine-induced relaxations of rat aortic rings and NO- or nitrergic nerve stimulation-induced relaxations of anococcygeus muscles. However, resorufin, an analogue of 7-ER, inhibited responses to acetylcholine, NO and GTN in rat aortic rings. 6. The results suggest that 7-ER inhibited responses to NO and nitrergic nerve stimulation through generation of superoxide radicals. However, an additional mechanism may be involved in the reduction in acetylcholine-induced response in aortic rings. 7. A 7-ER sensitive P450 system may be involved in the bioactivation of GTN and SNP in rat aortic rings, but not in rabbit aorta or rat anococcygeus muscles.
Topics: Acetylcholine; Animals; Aorta, Thoracic; Arginine; Binding, Competitive; Catalase; Cyclic GMP; Cytochrome P-450 Enzyme Inhibitors; Enzyme Inhibitors; In Vitro Techniques; Male; Muscle Relaxation; Muscle, Smooth, Vascular; Nitric Oxide; Oxazines; Rabbits; Rats; Rats, Sprague-Dawley; Superoxide Dismutase; Troleandomycin; Vasodilator Agents
PubMed: 8733576
DOI: 10.1111/j.1476-5381.1996.tb15366.x -
Antimicrobial Agents and Chemotherapy Nov 1986Escherichia coli BM2570 was resistant to high levels of erythromycin by two different mechanisms. The two genes conferring resistance to erythromycin in BM2570 were...
Escherichia coli BM2570 was resistant to high levels of erythromycin by two different mechanisms. The two genes conferring resistance to erythromycin in BM2570 were carried by a 150-kilobase self-transferable plasmid, pIP1527, and were cloned separately in E. coli. A single polypeptide with an Mr of 27,000 was encoded by the gene erxA and conferred high-level resistance to macrolide, lincosamide, and streptogramin B-type antibiotics by a mechanism other than drug inactivation. This resistance phenotype, not previously reported for a clinical isolate of enterobacteria, was probably due to modification of the ribosomes. The gene ereB encoded an enzyme with an Mr of 51,000 which inactivated erythromycin and oleandomycin. The two different mechanisms specified by erxA and ereB contributed in more than an additive fashion to the high level of resistance to erythromycin conferred by plasmid pIP1527 to E. coli BM2570.
Topics: Bacterial Proteins; Cloning, Molecular; Drug Resistance, Microbial; Erythromycin; Escherichia coli; Oleandomycin; Phenotype; R Factors
PubMed: 3541783
DOI: 10.1128/AAC.30.5.694 -
The Journal of Biological Chemistry Jul 1997Translation of a 5-codon mini-gene encoded in Escherichia coli 23 S rRNA was previously shown to render cells resistant to erythromycin (Tenson, T., DeBlasio, A., and... (Comparative Study)
Comparative Study
Translation of a 5-codon mini-gene encoded in Escherichia coli 23 S rRNA was previously shown to render cells resistant to erythromycin (Tenson, T., DeBlasio, A., and Mankin, A. S. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 5641-5646). Erythromycin resistance was mediated by a specific interaction of the 23 S rRNA-encoded pentapeptide with the ribosome. In the present study, peptides conferring erythromycin resistance were selected from in vivo expressed random peptide libraries to study structural features important for peptide activity. Screening of a 21-codon mini-gene library (the general structure ATG (NNN)20 TAA) demonstrated that only short peptides (3-6 amino acids long) conferred erythromycin resistance. Sequence comparison of erythromycin resistance peptides isolated from the 5-codon library (ATG (NNN)4 TAA) revealed a strong preference for leucine or isoleucine as a third amino acid and a hydrophobic amino acid at the C terminus of the peptide. When tested against other antibiotics, erythromycin resistance peptides rendered cells resistant to other macrolides, oleandomycin and spiramycin, but not to chloramphenicol or clindamycin. Defining the consensus amino acid sequence of erythromycin resistance peptides provided insights into a possible mode of peptide action and the nature of the peptide binding site on the ribosome.
Topics: Chromosome Mapping; Cloning, Molecular; Codon; Drug Resistance, Microbial; Erythromycin; Escherichia coli; Gene Library; Models, Molecular; Peptide Library; Peptides; Plasmids; RNA, Ribosomal, 23S; Sequence Analysis, DNA
PubMed: 9211885
DOI: 10.1074/jbc.272.28.17425 -
Clinical Pharmacology and Therapeutics Sep 1992The production of 14CO2 in the breath from an intravenous dose of [14C-N-methyl]-erythromycin (the erythromycin breath test [ERMBT]) and the measurement of the ratio of... (Comparative Study)
Comparative Study
The production of 14CO2 in the breath from an intravenous dose of [14C-N-methyl]-erythromycin (the erythromycin breath test [ERMBT]) and the measurement of the ratio of 6-beta-cortisol to free cortisol (6-beta-F/FF) in the urine have each been proposed as means of measuring hepatic P450IIIA catalytic activity in patients. We found that there was a significant correlation between the results of each test (r = 0.59, p less than 0.001) in 47 patients who were without liver disease and who were not taking medications believed to influence P450IIIA catalytic activity. In the 24 of these patients who were subsequently treated with the P450IIIA substrate cyclosporine, the ERMBT result was highly correlated with the mean trough cyclosporine blood level observed; however, there was no correlation between urinary 6-beta-F/FF and the cyclosporine blood levels. In a separate study of a patient during the anhepatic phase of liver transplantation surgery, the ERMBT result decreased by greater than 85%, whereas urinary 6-beta-F/FF decreased by just 50%. We conclude that the ERMBT and urinary 6-beta-F/FF do not always provide similar information about P450IIIA catalytic activity in patients, possibly because of extrahepatic production of 6-beta-F. Of the two tests, the ERMBT appears to provide the most relevant information for cyclosporine administration.
Topics: Aryl Hydrocarbon Hydroxylases; Breath Tests; Carbon Dioxide; Cyclosporine; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Humans; Hydrocortisone; Liver; Oxidoreductases, N-Demethylating; Psoriasis; Regression Analysis; Rifampin; Troleandomycin
PubMed: 1526083
DOI: 10.1038/clpt.1992.140 -
The Journal of Antibiotics Feb 1987Five macrolide antibiotics (erythromycin A, 1; oleandomycin, 3a; tylosin, 4a; spiramycins, 5a; leucomycin A3, 6a) have been phosphorylated enzymatically using cell-free...
Five macrolide antibiotics (erythromycin A, 1; oleandomycin, 3a; tylosin, 4a; spiramycins, 5a; leucomycin A3, 6a) have been phosphorylated enzymatically using cell-free extracts derived from Streptomyces coelicolor UC 5240. The necessary cofactors and the rates of the conversion have been determined.
Topics: Anti-Bacterial Agents; Erythromycin; Hydrogen-Ion Concentration; Leucomycins; Mass Spectrometry; Nucleotides; Oleandomycin; Phosphorylation; Streptomyces; Tylosin
PubMed: 3570968
DOI: 10.7164/antibiotics.40.195 -
The Journal of Antibiotics Oct 1988
Topics: Anti-Bacterial Agents; Chemical Phenomena; Chemistry; Lactones; Oleandomycin
PubMed: 3192503
DOI: 10.7164/antibiotics.41.1520 -
Journal of Dairy Science Feb 1998The in vitro effects of six doses (2 x 10(-3) to 2 x 10(-8) M) of antimicrobial drugs that are frequently used in udder infusions on the capacity of bovine blood...
The in vitro effects of six doses (2 x 10(-3) to 2 x 10(-8) M) of antimicrobial drugs that are frequently used in udder infusions on the capacity of bovine blood polymorphonuclear neutrophilic leukocytes to generate reactive oxygen species were studied by the measurement of luminol-dependent chemiluminescence after stimulation with phorbol 12-myristate 13-acetate. All drugs, except cloxacillin, significantly decreased chemiluminescence at the highest dose. Doxycyline induced the most severe inhibition, followed by neomycin and dihydrostreptomycin. The effect of ampicillin was due to the scavenging of reactive oxygen species and interactions with luminol. The inhibition observed with oleandomycin, neomycin, lincomycin, and dihydrostreptomycin was not due to direct effects on the production of oxidative metabolites but rather to interference with other components involved in the production of light, such as interference with the interaction between luminol and the myeloper-oxidase-H2O2-halide system. The deleterious effects of doxycycline can be explained by several factors: decreased production of superoxide, yellow color, the scavenging of reactive oxygen species, and Ca2+ chelating effect. In conclusion, the results of this study show that antibiotics may affect neutrophil function at concentrations that are reached in the mammary gland after local and repeated administration.
Topics: Ampicillin; Animals; Anti-Bacterial Agents; Cattle; Dihydrostreptomycin Sulfate; Doxycycline; Female; Hypochlorous Acid; Lincomycin; Luminescent Measurements; Luminol; Mastitis, Bovine; Neomycin; Neutrophils; Oleandomycin; Peroxidase; Respiratory Burst; Superoxides; Tetradecanoylphorbol Acetate
PubMed: 9532493
DOI: 10.3168/jds.S0022-0302(98)75590-0