A5023057218- DNA Repair Mechanisms
- DNA and Nucleic Acid Chemistry
- Bacterial Genetics and Biotechnology
- CRISPR and Genetic Engineering
- Redox biology and oxidative stress
- Advanced biosensing and bioanalysis techniques
- Carcinogens and Genotoxicity Assessment
- Photosynthetic Processes and Mechanisms
- Metalloenzymes and iron-sulfur proteins
- Heme Oxygenase-1 and Carbon Monoxide
- Nitric Oxide and Endothelin Effects
- Cancer therapeutics and mechanisms
- RNA and protein synthesis mechanisms
- Antibiotic Resistance in Bacteria
- Epigenetics and DNA Methylation
- Hemoglobin structure and function
- Trace Elements in Health
- Mitochondrial Function and Pathology
- Biochemical and Molecular Research
- Polyomavirus and related diseases
- Genomics, phytochemicals, and oxidative stress
- Neuroscience of respiration and sleep
- Neutrophil, Myeloperoxidase and Oxidative Mechanisms
- bioluminescence and chemiluminescence research
- Electron Spin Resonance Studies
Stony Brook University
2015-2024
Stony Brook School
2012-2024
Stony Brook Medicine
2018-2023
Harvard University
2002-2014
Milbank Memorial Fund
2010-2012
Stony Brook University Hospital
2010
Université Côte d'Azur
2009
Harvard University Press
1986-2006
Norwegian University of Science and Technology
2005
Massachusetts Institute of Technology
1988-2001
Escherichia coli responds to superoxide-generating agents by inducing approximately 40 proteins. We have identified a genetic locus, soxR (superoxide response), that positively regulates 9 of these proteins during superoxide stress. Induction under control is at the transcriptional level, as shown with lac fusions five paraquat-inducible promoters. Members regulon include least three demonstrable antioxidant roles: Mn-containing dismutase (which destroys radicals), endonuclease IV repairs...
Abasic (AP) sites are common, potentially mutagenic DNA damages that attacked by AP endonucleases. The biological roles of these enzymes in metazoans have not been tested. We cloned the human cDNA (APE) encodes main nuclear endonuclease. predicted Ape protein, which contains likely transport signals, is a member family repair includes two bacterial endonucleases (ExoA protein Streptococcus pneumoniae and exonuclease III Escherichia coli) Rrp1 Drosophila melanogaster. Purified lacks...
ABSTRACT Escherichia coli responds to oxidative stress by activating sets of coregulated genes that help the cell maintain homeostasis. Identified previously genetic and biochemical approaches, soxRS system mediates induction 18 these redox-inducible (including soxS gene itself). An overlapping set is activated an assortment structurally unrelated molecules with antibiotic activities; many in this response are controlled marRAB system. The activation either or results enhanced resistance...
Escherichia coli K-12 strains are normally tolerant to n-hexane and susceptible cyclohexane. Constitutive expression of marA the multiple antibiotic resistance (mar) locus or soxS robA gene product produced tolerance Inactivation mar locus, but not soxRS increased organic solvent susceptibility in wild type Mar mutants (to both cyclohexane). The hypersusceptibility is a newly described phenotype for robA-inactivated strain. Multicopy mar, soxS, induced cyclohexane with deleted inactivated...
Mutagenic abasic (AP) sites are generated directly by DNA-damaging agents or DNA glycosylases acting in base excision repair. AP corrected via incision endonucleases, removal of deoxyribose 5-phosphate, repair synthesis, and ligation. Mammalian polymerase β (Polβ) carries out most synthesis also can excise 5-phosphate after endonuclease incision. Yeast two-hybrid analysis now indicates protein–protein contact between Polβ human (Ape protein). In vitro , binding Ape protein to uncleaved loads...
Exposure of cells to hydrogen peroxide (H2O2) mediates adaptive responses or oxidative damage, depending on the magnitude challenge. Determining threshold for peroxide-mediated stress thus requires quantitation changes in endogenous H2O2 production. The intracellular steady-state concentrations were measured intact Escherichia coli under different conditions. Compounds that block electron transport at NADH dehydrogenase (rotenone) between ubiquinone and cytochrome b (antimycin) showed...
Nitric oxide is a free radical (NO) formed biologically through the oxidation of L-arginine by nitric synthases. NO produced transiently in mammalian cells for intercellular signaling and copious quantities to cause cytostasis cytotoxicity. In latter situation, deliberate cytotoxic product activated macrophages, along with other reactive oxygen species such as hydrogen peroxide (H2O2) superoxide (O2-). Escherichia coli has complex set responses H2O2 O2- that involves approximately 80...
Nitric oxide (NO) has diverse roles in intercellular communication and (at higher levels) immune-mediated cell killing. NO reacts with many cellular targets, cell-killing effects correlated to inactivation of key enzymes through nitrosylation their iron-sulfur centers. SoxR protein, a redox-sensitive transcription activator dependent on the oxidation state its binuclear ([2Fe-2S]) centers, is also activated Escherichia coli exposure macrophage-generated NO. We show here that activation by...
Journal Article Molecular characterization of the soxRS genes Escherichia coli : two control a superoxide stress regulon Get access Carlos F. Amábile-Cuevas, Amábile-Cuevas Laboratory Toxicology, Harvard School Public Health665 Huntington Avenue, Boston, MA 02115, USA Search for other works by this author on: Oxford Academic PubMed Google Scholar Bruce Demple * To whom correspondence should be addressed Nucleic Acids Research, Volume 19, Issue 16, 25 August 1991, Pages 4479–4484,...
The major apurinic/apyrimidinic (AP) endonuclease of human cells, the Ape protein, incises DNA adjacent to abasic sites initiate repair and counteract cytotoxic mutagenic effects AP sites. Here we address determinants activity using duplex substrates that contain synthetic analogs sites: tetrahydrofuranyl (F), propanediol (P), ethanediol (E), or 2-(aminobutyl)-1,3-propanediol (Q). last these, a branched structure, was poor substrate for which had kcat > 1000-fold lower than F. In contrast,...
Escherichia coli responds to the redox stress imposed by superoxide-generating agents such as paraquat activating synthesis of many 80 polypeptides. Expression a key group these inducible proteins is controlled at transcriptional level soxRS locus (the regulon). A two-stage control system was hypothesized for soxRS, in which an intracellular signal would trigger SoxR protein activator soxS gene and resulting increased levels SoxS activate transcription various regulon genes (B. Demple C.F....
Escherichia coli deficient in exonuclease III (xth gene mutants) are known to be hypersensitive hydrogen peroxide. We now show that such mutants accumulate many more DNA single-strand breaks than do wild-type bacteria upon exposure H2O2. isolated from H2O2-treated xth- cells contains strand not efficiently support synthesis by E. polymerase I, indicating the presence of blocking groups at 3' termini. Purified activates this blocked allow substantial I vitro. Another enzyme, endonuclease IV,...
Mammalian cells were investigated for enzymes that help correct oxidative damages in DNA. We focused on 3'-repair diesterases, which process DNA ends at strand breaks by removing 3′−blocking fragments of deoxyribose prevent repair synthesis. Two found a variety mouse, bovine and human tissues cultured cells. The two activities purified to differing degrees from HeLa One enzyme had the properties known AP endonuclease (M r −38,000, with identical substrate specificity reaction requirements,...
Escherichia coli treated with nontoxic levels of the superoxide-generating redox-cycling agents menadione and paraquat showed dramatic changes in protein composition as monitored by two-dimensional gel analysis. The distribution proteins synthesized after treatment these overlapped significantly that seen hydrogen peroxide treatment, it included all oxyR regulon. also elicited synthesis at least 33 other were not peroxide, including three heat shock proteins, Mn-containing superoxide...