Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:5.99.1.2 (topoisomerase)
 9,166 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Microcin B17 (MccB17) is a peptide antibiotic produced by Escherichia coli strains carrying the pMccB17 plasmid. MccB17 is synthesized as a precursor containing an amino-terminal leader peptide that is cleaved during maturation. Maturation requires the product of the chromosomal tldE (pmbA) gene. Mature microcin is exported across the cytoplasmic membrane by a dedicated ABC transporter. In sensitive cells, MccB17 targets the essential topoisomerase II DNA gyrase. Independently, tldE as well as tldD mutants were isolated as being resistant to CcdB, another natural poison of gyrase encoded by the ccd poison-antidote system of plasmid F. This led to the idea that TldD and TldE could regulate gyrase function. We present in vivo evidence supporting the hypothesis that TldD and TldE have proteolytic activity. We show that in bacterial mutants devoid of either TldD or TldE activity, the MccB17 precursor accumulates and is not exported. Similarly, in the ccd system, we found that TldD and TldE are involved in CcdA and CcdA41 antidote degradation rather than being involved in the CcdB resistance mechanism. Interestingly, sequence database comparisons revealed that these two proteins have homologues in eubacteria and archaebacteria, suggesting a broader physiological role.
 ...
PMID:The highly conserved TldD and TldE proteins of Escherichia coli are involved in microcin B17 processing and in CcdA degradation. 1202 38

Coxiella burnetii, an obligate intracellular Gram-negative bacterium, is the etiological agent of Q fever. This work takes advantage of a hypersensitive Escherichia coli genetic system to identify genes involved in resistance to nitrosative stress imposed by reactive nitrogen intermediates. Among the ten candidate genes identified, the transposase, UvrB and DNA topoisomerase IV are involved in DNA transaction; the sigma-32 factor and the putative DNA-binding protein may be involved in transcriptional regulation; IF-2 is involved in protein translation; malate dehydrogenase and carbamoyl-phosphate synthase are metabolic enzymes; and the ABC transporter is a membrane-bound protein. In addition, a hypothetical protein was identified. The role of the DNA repair gene uvrB in resistance to RNI was further confirmed by investigating the sensitivity of uvrB deletion mutant and complementation by C. burnetii uvrB. Deletion of two other components of the UvrABC nuclease, uvrA and uvrC also renders the cell sensitive to RNI. The relationship between UvrABC and nitrosative stress is discussed.
 ...
PMID:Screening of nitrosative stress resistance genes in Coxiella burnetii: Involvement of nucleotide excision repair. 2070 29

Streptococcus suis is a pathogen of zoonotic diseases. Moreover, the emergence of fluoro-quinolones (FQs) resistance in this pathogen has severe consequences for pigs and human health. In this study, the molecular mechanism of FQs resistance in S. suis type 2 (SS2) sensitive strains isolated from pigs was assessed after in vitro induction of resistance against the most frequently used FQs: ciprofloxacin, norfloxacin, and enrofloxacin. Proteome analysis, sequencing and real-time RT-PCR results strongly established an overexpression of an ABC transporter protein (other than SatAB) and topoisomerase mutations in GyrA (Ser81Arg), GyrB (Glu354Lys), and ParC (Ser79Phe) in contributing to high level ciprofloxacin resistance in SS2. Due to the overexpression of the ABC transporter, intracellular ciprofloxacin concentrations were significantly lower in the resistant strains than those of sensitive strains after 20, 35, and 60 min exposures to ciprofloxacin (p < 0.05). It was concluded that improper use of FQs is one of the main causes of the emergence of this zoonotic pathogen as a multiresistant organism against commonly used antibiotics. The existence of an efflux-like protein is an incentive to find new drug targets to avoid the spread of FQs-resistant S. suis isolates in pigs and the human population.
...
PMID:Overexpression of an ABC transporter and mutations of GyrA, GyrB, and ParC in contributing to high-level ciprofloxacin resistance in Streptococcus suis type 2. 2481 85

Flavonoids in nature are known to possess various activities such as anti-inflammatory, antimicrobial, anticancer, antioxidant, neuroprotective, anti-HIV activities etc., The molecular docking was performed by 26 naturally occurring flavonoids with selected targets COX-2, hydroxyacyl-ACP dehydratase, tyrosinase from Agaricus bisporus, isomaltase from Saccharomyces cerevisiae, Human IkB kinase beta, Human ABC transporter, topoisomerase II, topoisomerase IV, N-myristoyltransferase from Candida albicans, Peptide deformylase from Pseudomonas aeruginosa, polypeptide deformylase from Streptococcus pneumoniae. The analysis was based on docking score, glide energy, interactions type (bond type and distance) and interaction with amino acids. The top 5 flavonoids with best docking score was reported. The in-silico results provided for 26 naturally occurring flavonoid shows that they reduce the risk of inflammation, cancer and infectious disease if people have taken in diet continuously. The provided docking data of flavonoids may be useful to synthesis novel drug candidate for the mentioned targets.
 ...
PMID:Data on molecular docking of naturally occurring flavonoids with biologically important targets. 3207 1