Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026918 (Mycobacterium)
 52,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A genomic library of Mycobacterium bovis BCG has been constructed by cloning DNA partially digested with Sau3A into the Escherichia coli expression vector pAS1. The gene coding for ornithine carbamoyl-transferase (EC.2.1.3.3; OTCase), hereafter referred to as argF, was isolated from the library by complementation of a double argF-argI mutant of E. coli and its sequence was determined. The translation initiation codon used, GTG, was identified by comparing the amino acid sequence deduced from the gene with the N-terminal sequence of the corresponding purified protein. On this basis, the M. bovis BCG OTCase monomer consists of 307 amino acid residues and displays about 44% identity with other OTCases, the most closely related homologue being the anabolic enzyme of Pseudomonas aeruginosa. The native enzyme has an estimated molecular mass of 110 kDa, suggesting a trimeric structure as is the case for most of the anabolic OTCases known from various organisms.
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PMID:Molecular cloning, characterization and purification of ornithine carbamoyltransferase from Mycobacterium bovis BCG. 140 93

Ornithine decarboxylase (ODC), S-adenosyl-L-methionine decarboxylase (AMDC) and arginine decarboxylase (ADC) activities were detected for the first time in extracts of Mycobacterium bovis (BCG). All the decarboxylases differed from corresponding known bacterial decarboxylases in that: a) ODC did not require GTP for activity; b) ODC was not inhibited by any known inhibitor of bacterial ODCs; c) AMDC and ADC did not require Mg2+-ion for activity and were not markedly inhibited by any known inhibitor of the decarboxylases of other bacteria.
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PMID:Ornithine decarboxylase, S-adenosyl-L-methionine decarboxylase and arginine decarboxylase from Mycobacterium bovis (BCG). 354 91

1. The presence of a nucleoside triphosphate-dependent DNA-breakdown system was demonstrated in extracts of Mycobacterium smegmatis. Its activity was increased substantially by iron limitation, apparently after the fall in DNA content that took place under these conditions. A maximal activity of about 0.2mumole of deoxyribonucleotide/30min./mg. of protein was found in crude extracts. 2. After slight purification by streptomycin treatment, the enzyme showed maximal activity with undenatured DNA (K(m) approximately 200mug./ml.), ATP (K(m) approximately 1.2mm) or UTP, CTP and GTP giving lower activity and pyrophosphate giving none, and Mg(2+) ions (optimum concn. 12mm). The optimum pH was 8.5. 3. In the assay system there was proportionality between enzyme concentration and rate of reaction, but the rate fell off with time. 4. ATP was broken down in the reaction and monodeoxy-ribonucleotides were among the products, but the presence of some oligodeoxy-ribonucleotides was not excluded and the degree of phosphorylation of the primary products was uncertain.
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PMID:A nucleoside triphosphate-dependent deoxyribonucleic acid-breakdown system in Mycobacterium smegmatis, and the effect of iron limitation on the activity of this system. 578 68

Culture of Mycobacterium tuberculosis provides no information on the identity of a strain or the distribution of such a strain in the community. Strain identification of M. tuberculosis can help to address important epidemiological questions, e.g., the origin of an infection in a patient's household or community, whether reactivation of infection is endogenous or exogenous in origin, and the spread and early detection of organisms with acquired antibiotic resistance. To research this problem, strain identification must be reliable and accurate. Although genetic identification techniques already exist, it is valuable to have genetic identification techniques based on a number of genetic markers to improve the accurate identification of M. tuberculosis strains. We show that oligonucleotide (GTG)5 can be successfully applied to the identification of M. tuberculosis strains. This technique may be particularly useful in cases in which M. tuberculosis strains have few or no insertion elements (e.g., IS6110) or in identifying other strains of mycobacteria when informative probes are lacking.
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PMID:Oligonucleotide (GTG)5 as a marker for Mycobacterium tuberculosis strain identification. 791 7

Elongation factor Tu (EF-Tu) plays an important role in protein biosynthesis and is susceptible to antibiotics in prokaryotes like Escherichia coli. In order to understand the primary structure of EF-Tu in the intracellular pathogenic bacterium Mycobacterium leprae, the gene (tuf gene) coding for this protein was cloned and sequenced. The gene contains a coding region of 1,188 bp with GUG as start codon. The deduced amino acid sequence has 396 amino acids with a molecular weight of 43.6 kDa. Putative GTP-binding sites are located at amino acid positions 19-24, 83-87, and 138-141. Comparison of M. leprae EF-Tu amino acid sequence with those of M. tuberculosis, Micrococcus luteus, E. coli, and Salmonella typhimurium reveals 74-95% homology. Mitochondrial EF-Tu of Saccharomyces cerevisiae (62%) and chloroplast EF-Tu of Arabidopsis thalina (65.6%) also show strong homology with that of M. leprae. In contrast, the EF-Tu of the archaebacterium Halobacterium marismoruti exhibits relatively less homology (36.7%). Southern hybridization of M. leprae tuf gene with genomic DNA of slow growing and fast growing mycobacteria and related species like Corynebacterium fascians and Nocardia asteroides suggests that the gene is highly conserved in these organisms.
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PMID:Cloning and sequence determination of the gene coding for the elongation factor Tu of Mycobacterium leprae. 808 81

This paper reports the expression of a previously described gene [Nath and Laal, Nucleic Acids Res. 18 (1990) 4935], currently identified as the clpC gene of Mycobacterium leprae, using an in vitro rabbit reticulocyte lysate-coupled transcription/translation system. The produced protein moved as a 95-kDa band on SDS-PAGE. An additional band of 79 kDa was seen which may have resulted from a GTG codon downstream to the initiating ATG in the clpC sequence. A threefold increase in synthesis of the 95-kDa protein was achieved by altering the translation codon context sequence of the ATG start codon. The ClpC (caseinolytic protease C) amino acid sequence, which contained two nucleotide-binding sites, exhibited in vitro ATP binding. Of functional significance was its immunoreactivity in human subjects with mycobacterial infection. Leprosy and tuberculosis patients with active disease had antibodies which recognised ClpC in dot ELISA.
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PMID:Expression and functional characterisation of the clpC gene of Mycobacterium leprae: ClpC protein elicits human antibody response. 865

The gene for transcription termination factor Rho was isolated from Streptomyces lividans ZX7. It encoded a 77-kDa polypeptide (Rho 77) with considerable homology to known Rho factors. An atypical hydrophilic region of 228 residues was found within the N-terminal RNA-binding domain. Only Rho from Micrococcus luteus and Mycobacterium leprae (closely related GC-rich Gram-positive bacteria) had an analogous sequence. Rho 77 was overexpressed in Escherichia coli and purified using an N-terminal hexahistidine-tag. Rho 77 displayed a broad RNA-dependent ATPase activity, with poly(C) RNA being no more than 4-fold more effective than poly(A). This contrasts with the ATPase activity of Rho from E. coli which is stimulated primarily by poly(C) RNA. Rho 77 was a general RNA-dependent NTPase, apparent Km values for NTPs were: GTP 0.13 mM, ATP 0.17 mM, UTP 1.1 mM, and CTP >2 mM. Rho 77 poly(C)-dependent ATPase activity was inhibited by heparin, unlike the E. coli Rho. The antibiotic bicyclomycin inhibited the in vitro RNA-dependent ATPase activity of Rho 77, did not inhibit growth of streptomycetes but delayed the development of aerial mycelia. N-terminal deletion analysis to express a truncated form of Rho (Rho 72, 72 kDa) indicated that the first 42 residues of Rho 77 were not essential for RNA-dependent NTPase activity and were not the targets of inhibition by heparin or bicyclomycin.
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PMID:Isolation and sequencing of the rho gene from Streptomyces lividans ZX7 and characterization of the RNA-dependent NTPase activity of the overexpressed protein. 870 78

The use of the (GTG)5 oligonucleotide, a repetitive marker in the Mycobacterium tuberculosis chromosome, as a primer in association with an IS6110 outlooking primer has been successfully applied to a PCR-based fingerprinting method. This method classified 62 strains of M. tuberculosis, isolated from human immunodeficiency virus-seropositive and -seronegative patients in different regions of Italy and Pakistan, as having 53 different patterns. The results were compared with traditional IS6110 fingerprinting, by which 47 distinct patterns were observed.
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PMID:Molecular epidemiology of Mycobacterium tuberculosis strains isolated from different regions of Italy and Pakistan. 878 2

Two highly polymorphic Mycobacterium tuberculosis genomic domains, characterized by hybridization to the oligonucleotide (GTG)5, were identified as potential DNA fingerprinting probes. These domains were cloned [pMTB484(1) and pMTB484(2K4), respectively] and shown to be useful for genotype analysis by Southern blotting. These probes were used to genotype geographically linked strains of M. tuberculosis previously shown to have identical IS6110 fingerprints. Subsequent DNA fingerprints generated with MTB484(1) and MTB484(2K4) showed a high degree of polymorphism, allowing subclassification of IS6110-defined clusters into composites of smaller clusters and unique strains. Correlation of the molecular data with patient interviews and clinical records confirmed the sensitivity of these probes, as contacts were established only within subclusters. These findings demonstrate the requirement for multiple probes to accurately classify M. tuberculosis strains, even those with high copy numbers of IS6110. The enhanced accuracy of strain typing should, in turn, further our understanding of the epidemiology of tuberculosis.
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PMID:Genotyping of Mycobacterium tuberculosis with additional markers enhances accuracy in epidemiological studies. 886 88

We determined the nucleotide sequence of a 6-kb DNA region harboring the recF, orf192, gyrB, and gyrA genes from Mycobacterium smegmatis mc(2)155. The amino acid sequences deduced from gyrA and gyrB displayed 89 and 86% identity, respectively, with the DNA gyrase from Mycobacterium tuberculosis, and 67 and 65% identity, respectively, with that from Streptomyces coelicolor. An open reading frame encoding the C-terminal region of the M. smegmatis RecF polypeptide was found upstream from gyrB and was 57% identical to the open reading frame encoding the C-terminal region of the S. coelicolor RecF protein. The gene orf192 was identified between recF and gyrB and was 39% identical to orf191 found in S. coelicolor in the recF-gyrB region. The M. smegmatis DNA gyrase, which was purified by affinity chromatography on novobiocin-Sepharose, consisted of two polypeptides with apparent molecular masses of 98 and 80 kDa. Determination of the N-terminal amino acid sequence of the B subunit confirmed GTG as the start codon in gyrB. Analysis of the supercoiling activity of the enzyme indicated that the M. smegmatis DNA gyrase was characterized by a specific activity equivalent to that of the Escherichia coli DNA gyrase. Inhibition of this activity by 4-quinolones was investigated by determining the 50% inhibitory concentrations (IC50S) of nalidixic acid, ofloxacin, and ciprofloxacin. The results indicated that the inhibitory activities of these drugs against the M. smegmatis DNA gyrase were markedly lower than those previously reported for the E. coli DNA gyrase. The results also suggested that the higher levels of activity of ofloxacin and ciprofloxacin against M. smegmatis (MICs, 0.5 to 1 microgram/ml), in contrast to that of nalidixic acid (MIC, 256 micrograms/ml), could be related to the higher inhibitory activities of fluoroquinolones against the DNA gyrase from this species (IC50S, 7 to 14 micrograms/ml) compared with that of nalidixic acid (IC50, 1,400 micrograms/ml).
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PMID:Sequence analysis, purification, and study of inhibition by 4-quinolones of the DNA gyrase from Mycobacterium smegmatis. 887 80


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