Julien Brochu, Émilie Vlachos-Breton, S. Sutherland, Makisha Martel, Marc Drolet,
... coli has two type 1A topos, topo I (topA) and topo III (topB). Topo I relaxes negative ... part to inhibit R-loop formation. To grow, topA mutants acquire compensatory mutations, base substitutions in gyrA ... gyrB(Ts) compensatory mutation was used to construct topA topB null mutants. These mutants form very long ... of the chromosome that is more active in topA topB cells than in topA and rnhA (RNase HI) null cells. The S9. ... show the accumulation of R-loops in rnhA, topA and topA topB null cells. Moreover topA topB ...
Tópico(s): DNA and Nucleic Acid Chemistry
2018 - Public Library of Science | PLoS Genetics
Qingxuan Zhou, Yan Zhou, Ding Jun Jin, Yuk‐Ching Tse‐Dinh,
Escherichia coli topoisomerase I (TopA), a regulator of global and local DNA supercoiling, is modified by Nε-Lysine acetylation. The NAD+-dependent protein deacetylase CobB ... of CobB in a ΔcobB mutant reduces intracellular TopA catalytic activity and increases negative DNA supercoiling. TopA expression level is elevated as topA transcription responds to the increased negative supercoiling. The ... be partially compensated by further increase of intracellular TopA level via overexpression of recombinant TopA. The relaxation ...
Tópico(s): Epigenetics and DNA Methylation
2017 - Oxford University Press | Nucleic Acids Research
Agnieszka Strzałka, Marcin Szafran, Terence R. Strick, Dagmara Jakimowicz,
Streptomyces topoisomerase I (TopA) exhibits exceptionally high processivity. The enzyme, as other actinobacterial topoisomerases I, differs from its bacterial homologs in its C- ... lysine repeats is a characteristic feature of actinobacterial TopA CTDs. Streptomyces TopA contains the longest stretch of lysine repeats, which ... studies revealed that the lysine repeats stabilized the TopA–DNA complex, while single-molecule experiments showed that their elimination impaired enzyme processivity. Streptomyces coelicolor TopA processivity could not be restored by fusion of ...
Tópico(s): Biochemical and Molecular Research
2017 - Oxford University Press | Nucleic Acids Research
Jianxin Lü, Wu Wang, Guoqiang Tan, Aaron P. Landry, Peng Yi, Fan Si, Yaguang Ren, Huangen Ding,
Escherichia coli topoisomerase I (TopA) cleaves and rejoins one strand of double-stranded DNA to relax the negatively supercoiled DNA. Structurally, TopA contains an N-terminal catalytic fragment and a ... supercoiled DNA. Here we report that E. coli TopA is an iron and zinc binding protein. The ... absorption measurements and metal content analyses reveal that TopA purified from E. coli cells grown in the ... LB medium contains both iron and zinc. However, TopA purified from E. coli cells grown in the ... minimal medium produces the zinc- or iron-bound TopA, respectively. Whereas the zinc-bound TopA is fully ...
Tópico(s): DNA Repair Mechanisms
2011 - Springer Science+Business Media | BioMetals
Ryosuke L. Ohniwa, Kazuya Morikawa, Joongbaek Kim, Toshiko Ohta, Akira Ishihama, Chieko Wada, Kunio Takeyasu,
... and DNA gyrase. In the Δfis strain, both topA and gyrA/B genes were found to be ... to work as a transcription regulator for the topA, gyrA and gyrB genes, each coding for Topoisomerase ... gyrB- and dps-mRNAs. The levels of (A) topA-, (B) gyrA- and (C) gyrB-mRNAs in the ... 2004), and the increase in negative supercoil facilitates topA expression (Menzel and Gellert, 1983; Mizushima et al, ... overexpressing cells. Figure 6.Northern blot analyses of topA-, gyrA-, gyrB- and fis-mRNAs under the overexpression ... I and DNA gyrase. The levels of (A) topA-mRNA in DNA gyrase++, (B, C) gyrA- and ...
Tópico(s): Escherichia coli research studies
2006 - Springer Nature | The EMBO Journal
Vera A. Stupina, James C. Wang,
The viability of the topA mutants lacking DNA topoisomerase I was thought to depend on the presence of compensatory mutations in Escherichia coli but not ... typhimurium or Shigella flexneri. This apparent discrepancy in topA requirements in different bacteria prompted us to reexamine the topA requirements in E. coli. We find that E. coli strains bearing topA mutations, introduced into the strains by DNA-mediated ... or 42 °C without any compensatory mutations. These topA- cells exhibit cold sensitivity in their growth, however, ...
Tópico(s): Bioactive Compounds and Antitumor Agents
2004 - Elsevier BV | Journal of Biological Chemistry
Yong Wang, A. Simon Lynch, Sue-Jane Chen, James C. Wang,
Studies of two temperature-sensitiveEscherichia coli topA strains AS17 and BR83, both of which were supposed to carry a topA amber mutation and a temperature-sensitive supD43,74 amber- ... itself temperature-sensitive. Nucleotide sequencing of the AS17 topA allele and studies of its expected cellular product ... any osmolarity. Studies of two temperature-sensitiveEscherichia coli topA strains AS17 and BR83, both of which were supposed to carry a topA amber mutation and a temperature-sensitive supD43,74 ... itself temperature-sensitive. Nucleotide sequencing of the AS17 topA allele and studies of its expected cellular product ...
Tópico(s): DNA Repair Mechanisms
2002 - Elsevier BV | Journal of Biological Chemistry
Chadi Hraiky, Marc-André Raymond, Marc Drolet,
... during transcription elongation. Indeed, the growth problem of topA (encoding DNA topoisomerase I) null mutants was shown ... RNase H required to stimulate the growth of topA null mutants (7.Drolet M. Phoenix P. Menzel ... inhibitory effects is still unknown. The fact that topA null mutants are sensitive to changes in environmental ... PubMed Scopus (206) Google Scholar). Indeed, such a topA null mutant is able to grow at 37 ° ... MA249 and MA251). Densitometry analysis reveals that the topA null mutant (MA251) synthesized at least three times ...
Tópico(s): Antibiotic Resistance in Bacteria
2000 - Elsevier BV | Journal of Biological Chemistry
... activities of DNA topoisomerase I, encoded by the topA gene, which specifically relaxes negative supercoiling, and DNA ... these parameters and the growth of the various topA mutants. Our results indicate that the essential function ... constructionRFM475rpsL galK2, Δlac74, gyrB221(couR), gyrB203(Ts) Δ(topA cysB)20413Drolet M. Phoenix P. Menzel R. Massé ... 92: 3526-3530Crossref PubMed Scopus (198) Google ScholarDM800Δ(topA cysB)204 gyrB225, acrA132Pruss G.J. Manes S. ... the extraction of hypernegatively supercoiled plasmid DNAs from topA null mutants (5Wu H.Y. Shyy S.H. ...
Tópico(s): DNA Repair Mechanisms
1999 - Elsevier BV | Journal of Biological Chemistry
... supercoiled plasmid DNAs, is observed under conditions where topA mutants fail to grow. Furthermore, we have demonstrated ... supercoiled plasmid DNAs, is observed under conditions where topA mutants fail to grow. Furthermore, we have demonstrated ... RNase H overproduction stimulates the growth of the topA null mutants used to demonstrate this correlation (5Drolet ... our in vivo experiments were performed in a topA null mutant. In addition, because the presence of ... could potentially be a problem, we used a topA null mutant that grows better when RNase H ...
Tópico(s): DNA Repair Mechanisms
1999 - Elsevier BV | Journal of Biological Chemistry
Serge Gangloff, Bernard de Massy, L. Beaudet Arthur, Rodney Rothstein, Francis Fabre,
... involved in this process, since expression of bacterial TopA in yeast top3Δ mutants permits sporulation. The meiotic ... yeast. It is homologous to the Escherichia coli topA and topB genes but not to the S. ... Top3 protein exhibits many of the properties of TopA and TopB, including relaxation of only negatively supercoiled ... recombinant molecules. Additionally, overexpression of the E.coli topA gene restores sporulation, which suggests that a type ... dyads) were scored. ND, not determined. Overexpression of TopA suppresses the sporulation deficiency of top3Δ mutants Wallis ...
Tópico(s): Plant nutrient uptake and metabolism
1999 - Springer Nature | The EMBO Journal
Suppression of leu-500 mutation in Salmonella typhimurium topA − strains has been one of the most fascinating ... the activation of the leu-500 promoter in topA − strains. Our recent studies have shown that ilvIH ... promoter relay can result in leu-500activation in topA + strains. In addition, suppression of the chromosomal leu- ... activities of ilvIH and leuO rather than the TopA level in thetopA + strain. It appears that theleu-500 suppression in a topA −strain is due to the constant ilvIH transcription ... Suppression of leu-500 mutation in Salmonella typhimurium topA − strains has been one of the most fascinating ...
Tópico(s): RNA Interference and Gene Delivery
1998 - Elsevier BV | Journal of Biological Chemistry
Dongrong Chen, Sophie Bachellier‐Bassi, David M.J. Lilley,
... the −10 region but can be activated in topA Escherichia coli and Salmonella strains. We have found ... the −10 region but can be activated in topA Escherichia coli and Salmonella strains. We have found ... The later demonstration that supX was identical to topA(4Margolin P. Zumstein L. Sternglanz R. Wang J. ... demonstration of a direct requirement for a null topA background (8Richardson S.M.H. Higgins C.F. ... gene, which would be less efficiently relaxed in topA cells. Although this model could explain the activation ...
Tópico(s): Bacterial Genetics and Biotechnology
1998 - Elsevier BV | Journal of Biological Chemistry
Minae Mure, Katsuyuki Tanizawa,
2,4,5-Trihydroxyphenylalanine (6-hydroxydopa, abbreviated as topa) is a perhydroxylated derivative of an amino acid, ... redox capacity. In addition, the oxidized form of topa, topa quinone, has been shown to be an active ... glutamatergic agonist and to produce neuronal cell death. Topa and topa quinone may be biosynthesized enzymatically and non-enzymatically ... from tyrosine through dopa. On the other hand, topa quinone bound covalently in a protein has been identified in copper amine oxidase, in which topa quinone serves as an essential cofactor in catalyzing ...
Tópico(s): Electrochemical sensors and biosensors
1997 - Oxford University Press | Bioscience Biotechnology and Biochemistry
Danying Cai, Neal K. Williams, Judith P. Klinman,
... self-processing mechanism for 2,4,5-trihydroxyphenylalanine (topa) quinone biogenesis involving the active site copper (Cai, ... however, it has not been possible to initiate topa quinone formation by the addition of exogenous copper ... copper first to apoprotein leads to formation of topa quinone and stable activity in the presence of ... little or no exchange. The data confirm that topa quinone biogenesis in the H. polymorpha system is ... self-processing mechanism for 2,4,5-trihydroxyphenylalanine (topa) quinone biogenesis involving the active site copper (Cai, ...
Tópico(s): Biochemical Acid Research Studies
1997 - Elsevier BV | Journal of Biological Chemistry
TA Newcomer, Paul A. Rosenberg, Elias Aizenman,
The quinone derivative of 2,4,5-trihydroxyphenylalanine (TOPA) is a selective non-NMDA agonist and excitotoxin. ... containing physiological solutions have been shown to generate TOPA and TOPA quinone (TOPA compounds), there have been no previous reports demonstrating ... catecholaminergic clonal cell line (PC12), we have identified TOPA compounds as by-products of catecholamine synthesis. PC12 ... 0.2 pmol/10(6) cells of total TOPA compounds. The formation of these compounds could be ... 30 microM NSD-1015) increased the formation of TOPA compounds in both the unstimulated and stimulated conditions ...
Tópico(s): Ion channel regulation and function
1995 - Society for Neuroscience | Journal of Neuroscience
Kenji Kano, Toshio Mori, Bunji Ono, Masashi Goto, Tokuji Ikeda,
Electrochemical characterization of topa quinone (6-hydroxydopa quinone), the organic cofactor of copper-containing amine oxidases, has been performed with the aid of spectroscopy and ab initio energy minimization technique. Topa quinone exhibits a totally reversible cyclic voltammogram at ... to a two-step one-electron conversion between topa quinone and topa via topa semiquinone intermediate. Digital simulation of the reversible wave ... dissociation constants of the phenolic hydroxyl groups of topa quinone, topa semiquinone and topa have been evaluated ...
Tópico(s): Metal-Catalyzed Oxygenation Mechanisms
1993 - Elsevier BV | Biochimica et Biophysica Acta (BBA) - General Subjects
Timothy A. Newcomer, Alan M. Palmer, Paul A. Rosenberg, Elias Aizenman,
2,4,5-Trihydroxyphenylalanine (TOPA) oxidizes in solution to form a quinone derivative that is a non-N-methyl-D-aspartate agonist and neurotoxin. Although ... have been postulated for the formation of both TOPA and TOPA quinone from closely related catecholamines, the generation of ... dual electrode coulometric detector was used to analyze TOPA containing solutions in an effort to rigorously characterize ... obtain optimal conditions to selectively detect and quantify TOPA and TOPA quinone from closely related catecholamines. TOPA ...
Tópico(s): Electrochemical sensors and biosensors
1993 - Wiley | Journal of Neurochemistry
Niamh Ní Bhriain, Charles J. Dorman,
... a homologue of the Escherichia coli K‐12 topA gene which encodes DNA topoisomerase I. The S. flexneri topA gene was replaced by a copy of the E. coli K‐12 topA gene which has been insertionally inactivated by transposon ... reporter plasmids showed that the presence of this topA lesion in S. flexneri correlated with an increase ... coli and Salmonella typhimurium. The introduction of the topA mutation also resulted in repression of transcription of ... the 230 kb virulence plasmid. In addition, the topA mutant was hypersensitive to growth medium osmolarity, was ...
Tópico(s): Escherichia coli research studies
1993 - Wiley | Molecular Microbiology
... Electrolytically Coloured Pb++-Doped Alkali Halide Crystals V. Topa, V. Topa Institute Physics, Academy of the Socialist Republic of ... BucharestSearch for more papers by this author V. Topa, V. Topa Institute Physics, Academy of the Socialist Republic of ... URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat References 1 V. Topa, Thesis, Bucharest 1966 (unpublished). 2 V. Topa, Rev. Roum. Phys. 12, 781 (1967). 3 W. Kleemann, Z. Phys. 214, 285 (1968). 4 V. Topa, Internat. Symp. on Color Centers, Rome 1968. 5 ...
Tópico(s): Solid-state spectroscopy and crystallography
1969 - Wiley | physica status solidi (b)
Yan Rong, Shikun Hu, Ning Ma, Peiqing Song, Qingqing Liang, Huiqun Zhang, Yanqi Li, Lixin Shen, Kangmin Duan, Lin Chen,
... the potential regulatory role of a topoisomerase I (TopA) in Pseudomonas aeruginosa, we investigated a previously isolated topA mutation using genetic approaches. We here report the ... biofilm initiation, and pyocyanin production. We found that topA was essential in P. aeruginosa, but a transposon ... acid residues at the C-terminal of the TopA and a mutant, named topA-RM, in which topA was split into three fragments were viable. The reduced T3SS expression in topA-RM seemed to be directly related to TopA ...
Tópico(s): Bacterial Genetics and Biotechnology
2019 - Multidisciplinary Digital Publishing Institute | International Journal of Molecular Sciences
Chien‐Chung Chen, Ming Fang, Arundhati Majumder, Hai-Young Wu,
... 500 promoter (pleu-500) is activated in the topA mutants is intriguing (3Richardson S.M.H. Higgins ... that activation of plasmid-borne pleu-500 in topA mutants requires an upstream transcriptional activity transcribing away ... 5′-AATTCAATCCGCCGTTTGTTCCCACGGAGAATCCGACGGGTTGTTACTGGTACC-3′; and 5′-CATTTAATGTTGATGAAAGCTGGCTACAGGAAGGCCAGACGCGAAAGCTTGTAC-3′. CH601(topA +) and CH582(topA −), an isogenic pair of S. typhimurium strains, were ... inducible pleu-500 activation in S. typhimurium CH582 (topA −), regardless of the presence or absence of LeuO ( ...
Tópico(s): Genomics and Chromatin Dynamics
2001 - Elsevier BV | Journal of Biological Chemistry
D Chen, Richard P. Bowater, David M.J. Lilley,
... 500 promoter of Salmonella typhimurium is activated in topA mutants. We have previously shown that this promoter ... related pair of E. coli strains DM800 (delta topA) and SD108 (topA+) shows that the activation is dependent on the presence of a null mutation in topA. We have also shown that activation of the ... gene, is extracted from E. coli DM800 (delta topA), the distribution of linking numbers is bimodal. There ... constant for all plasmids extracted from either delta topA or topA+ cells. In addition, we observe a ...
Tópico(s): Antibiotic Resistance in Bacteria
1994 - American Society for Microbiology | Journal of Bacteriology
J. Krishna Leela, Nalini Raghunathan, J. Gowrishankar,
... I (Topo I) of Escherichia coli, encoded by topA, acts to relax negative supercoils in DNA. Topo ... cSDR), but some uncertainty persists as to whether topA is essential for viability in E. coli and related enterobacteria. Here, we show that several topA alleles, including ΔtopA, confer lethality in derivatives of ... Four phenotypes related to cSDR were identified for topA mutants: (i) one of the topA alleles rescued ΔdnaA lethality; (ii) in dnaA+ derivatives, ... in the terminus region of the chromosome; (iii) topA was synthetically lethal with rnhA (encoding RNase HI, ...
Tópico(s): Antibiotic Resistance in Bacteria
2021 - American Society for Microbiology | Journal of Bacteriology
M.T. Garcı́a, María Amparo Blázquez, María-José Ferrándiz, María‐Jesús Sanz, N. Silva-Martin, J.A. Hermoso, Adela G. de la Campa,
... a single type I enzyme (DNA-topoisomerase I, TopA), as demonstrated here. Although fluoroquinolones target type II enzymes, antibiotics efficiently targeting TopA have not yet been reported. Eighteen alkaloids (seven ... boldine and used to test inhibition both of TopA activity and of cell growth. Two phenanthrenes (seconeolitsine and N-methyl-seconeolitsine) effectively inhibited both TopA activity and cell growth at equivalent concentrations (∼17 μM). Evidence for in vivo TopA targeting by seconeolitsine was provided by the protection ...
Tópico(s): Antibiotics Pharmacokinetics and Efficacy
2010 - Elsevier BV | Journal of Biological Chemistry
Bokun Cheng, Chang-Xi Zhu, Chengling Ji, Adriana Ahumada, Yuk-Ching Tse-Dinh,
Escherichia coli DNA topoisomerase I (encoded by the topA gene) is important for maintaining steady-state DNA ... Escherichia coli DNA topoisomerase I (encoded by the topA gene) is important for maintaining steady-state DNA ... Escherichia coli DNA topoisomerase I (encoded by the topA gene) is the most extensively studied example of ... topoisomerase I function due to mutation in the topA gene, the accumulation of hypernegative supercoiling can lead ... the copurification was reduced in extracts from a topA mutant strain, suggesting that the interaction between RNA ...
Tópico(s): Bioactive Compounds and Antitumor Agents
2003 - Elsevier BV | Journal of Biological Chemistry
Ivo Frébort, Pavel Peč, Lenka Luhová, Hirohide Toyama, Kazunobu Matsushita, Shun Hirota, Teizo Kitagawa, Tamio Ueno, Yasuhisa Asano, Yasuo Kato, Osao Adachi,
... published for other copper amine oxidases and to topa hydantoin p-nitrophenylhydrazone. After digestion by thermolysin and ... HPLC and sequenced. For thermolytic peptides, a typical topa consensus sequence, Asn-X-Glu-Tyr, was obtained ... and mass spectroscopy confirmed the residue X as topa p-nitrophenylhydrazone in AO-II and revealed the ... hydrolysis and identified as a product derived from topa quinone. The data, together with amino-acid sequence of AO-I, confer strong evidence for topa quinone as the cofactor, bound in the typical ...
Tópico(s): Biochemical Acid Research Studies
1996 - Elsevier BV | Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics
Paul Deegan, Eithne Mulloy, Walter T. McNicholas,
Topical oropharyngeal anesthesia (TOPA) increases obstructive sleep apnea (OSA) frequency in both normal subjects and loud snorers. The effects of TOPA in established OSA were assessed in six male ... underwent two overnight sleep studies, randomly assigned to TOPA (10% lidocaine spray and 0.25% bupivocaine gargle) ... SEM) during C and 88 +/- 2.9% during TOPA. Overall apnea-hypopnea (AH) frequency, using inductance plethysmography, ... versus 25.1 +/- 3.5 events/h on TOPA nights (p = 0.12). There was no significant increase in AH duration with TOPA, and oxygen desaturation (> or = 4%) frequency was similar: ...
Tópico(s): Pediatric Pain Management Techniques
1995 - American Thoracic Society | American Journal of Respiratory and Critical Care Medicine
P C Deegan, E Mulloy, Walter T. McNicholas,
Topical oropharyngeal anesthesia (TOPA) increases obstructive sleep apnea (OSA) frequency in both normal subjects and loud snorers. The effects of TOPA in established OSA were assessed in six male ... underwent two overnight sleep studies, randomly assigned to TOPA (10% lidocaine spray and 0.25% bupivocaine gargle) ... SEM) during C and 88 +/- 2.9% during TOPA. Overall apnea-hypopnea (AH) frequency, using inductance plethysmography, ... versus 25.1 +/- 3.5 events/h on TOPA nights (p = 0.12). There was no significant increase in AH duration with TOPA, and oxygen desaturation (> or = 4%) frequency was similar: ...
Tópico(s): Tracheal and airway disorders
1995 - American Thoracic Society | American Journal of Respiratory and Critical Care Medicine
Kazuo Shishido, Naoki Komiyama, S Ikawa,
... deletion of the DNA topoisomerase I gene (delta topA) with a compensatory mutation of the DNA gyrase gene (gyrA or gyrB) and from their TopA+ transductants was analyzed by agarose gel electrophoresis followed ... DNA molecules was a knotted species in the topA+ gyr+ strains W3110 and DM4100, while strains DM750 (delta topA gyrA224), DM800 (delta topA gyrB225), SD275 (topA+ gyrA224) and SD108 (topA+ gyrB225) produced six to ten times as much knotted DNA as the topA+ gyr+ controls. The results suggest that the increased ...
Tópico(s): Lung Cancer Research Studies
1987 - Elsevier BV | Journal of Molecular Biology