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2 results on '"supercoil DNA"'

1. Effects of the Ligand Structure of Cu(II) Complexes on Oxidative DNA Cleavage.

Author

Han, Ji Hoon, Kim, Ji Hoon, Jung, Maeng‐Joon, Kim, Seog K., and Jang, Yoon Jung

Subjects
*DNA, *LINEAR dichroism, *REACTIVE oxygen species, *HYDROXYL group, *LIGANDS (Chemistry), *FUNCTIONAL groups
Abstract

Cu complexes were synthesized by substituting the hydrogen of the amine group of basic ligand 2,2′‐dipicoylamine (dpca) (complex 2) with CH3CO (complex 1), phenyl (complex 3), and methyl (complex 4), respectively, and their DNA cleavage activity was investigated using linear dichroism (LD) and electrophoresis. The DNA cleavage efficiencies of Cu complexes 3 and 4 with phenyl and methyl, which are electron‐donating functional groups, turned out to be the highest, and LD magnitudes rapidly decreased at 260 nm. In particular, Cu complex 3 showed a rapid LD magnitude reduction to 63% of the total for 90 min, and to 50% of the total at 12 min. DNA cleavage efficiencies were high in the order of phenyl > methyl > HCH3CO, and the highest DNA cleavage efficiency was observed in the presence of electron‐donating groups. The electrophoresis results are also consistent with the changes in LD spectra over time. The Cu complexes (1–4) were found to cleave DNA through oxidative pathways, and the major reaction oxygen species involved in DNA cleavage were the superoxide radical (·O2−), singlet oxygen (1O2), and hydroxyl radical (·OH). [ABSTRACT FROM AUTHOR]

Published
2021
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2. A novel chromatin‐forming histone H1 homologue is encoded by a dispensable and growth‐regulated gene in Bordetella pertussis

Author

Riccardo Manetti, Anna Prugnola, Sophie Goyard, Stefano Ricci, Agnes Ullmann, Patrizia Polverino-De-Laureto, Rino Rappuoli, Vincenzo Scarlato, Beatrice Aricò, Roberto Manetti, Scarlato V., Arico B., Goyard S., Ricci S., Manetti R., Prugnola A., Polverino-De-Laureto P., Ullmann A., and Rappuoli R.

Subjects
DNA, Bacterial, Transcription, Genetic, Molecular Sequence Data, Regulatory Sequences, Nucleic Acid, SAP30, Microbiology, Bordetella pertussis, Histones, DNA replication factor CDT1, Bacterial Proteins, Histone H1, Kanamycin, histone-like protein, Consensus Sequence, Histone H2A, Deoxyribonuclease I, Amino Acid Sequence, supercoil DNA, Molecular Biology, Base Sequence, Sequence Homology, Amino Acid, biology, DNA, Superhelical, Single-Strand Specific DNA and RNA Endonucleases, DNA replication, Nuclear Proteins, Gene Expression Regulation, Bacterial, Biological Evolution, Molecular biology, Chromatin, Histone, biology.protein, DNA supercoil, Sequence Analysis
Abstract

We report the Identification of a protein homologous to a histone H1 in Bordetella pertussis. The B. pertussis histone homologue, BpH1, varies in size in different strains from 182 to 206 amino acids. The variability of the size of the protein is due to gene variability by insertion or deletion of DNA modules. Insertion of a kanamycin cassette into the bpH1 gene generates a BpH1 null mutant with phenotypic properties and growth rate similar to those of the wild‐type strain, showing that this gene is dispensable. In vitro, the BpH1 protein prevents chromosomal DNA degradation from DNase I and constrains supercoiled DNA. Transcription of the bpH1 gene is activated during exponential growth of the bacteria, whereas It is repressed during the stationary phase of growth, It is proposed that BpH1 plays a role in chromatin formation and condensation during DNA replication and that repression of transcription depends upon a reduced rate of DNA replication. Copyright © 1995, Wiley Blackwell. All rights reserved

Published
1995

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