Wheat (Triticum vulgare) Chloroplast Nuclease ChSI Exhibits 5‘ Flap Structure-Specific Endonuclease Activity
| ISSN: | 1520-4995 0006-2960 |
|---|---|
| DOI: | 10.1021/bi049947u |
| Přístupová URL adresa: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f4da689e61046164562f089961756859 https://doi.org/10.1021/bi049947u |
| Přírůstkové číslo: | edsair.doi.dedup.....f4da689e61046164562f089961756859 |
| Autor: | Barbara Nawrot, Krzysztof Olszak, Elzbieta Kuligowska, Anna Przykorska, Gerard Keith, Karina Solecka |
| Rok vydání: | 2004 |
| Předmět: |
Exonucleases
Exonuclease Chloroplasts DNA Plant Flap Endonucleases DNA repair DNA damage Oligonucleotides DNA Single-Stranded Biology Biochemistry Catalysis Substrate Specificity Structure-Activity Relationship chemistry.chemical_compound Endonuclease Triticum chemistry.chemical_classification Nuclease Hydrolysis Molecular biology Kinetics Chloroplast stroma Enzyme chemistry Spectrometry Mass Matrix-Assisted Laser Desorption-Ionization biology.protein Nucleic Acid Conformation Thermodynamics DNA |
| Zdroj: | Biochemistry. 43:11283-11294 |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi049947u |
| Popis: | The structure-specific ChSI nuclease from wheat (Triticum vulgare) chloroplast stroma has been previously purified and characterized in our laboratory. It is a single-strand-specific DNA and RNA endonuclease. Although the enzyme has been initially characterized and used as a structural probe, its biological function is still unknown. Localization of the ChSI enzyme inside chloroplasts, possessing their own DNA that is generally highly exposed to UV light and often affected by numerous redox reactions and electron transfer processes, might suggest, however, that this enzyme could be involved in DNA repair. The repair of some types of DNA damage has been shown to proceed through branched DNA intermediates which are substrates for the structure-specific DNA endonucleases. Thus we tested the substrate specificity of ChSI endonuclease toward various branched DNAs containing 5' flap, 5' pseudoflap, 3' pseudoflap, or single-stranded bulged structural motifs. It appears that ChSI has a high 5' flap structure-specific endonucleolytic activity. The catalytic efficiency (k(cat)/K(M)) of the enzyme is significantly higher for the 5' flap substrate than for single-stranded DNA. The ChSI 5' flap activity was inhibited by high concentrations of Mg(2+), Mn(2+), Zn(2+), or Ca(2+). However, low concentrations of divalent cations could restore the loss of ChSI activity as a consequence of EDTA pretreatment. In contrast to other known 5' flap nucleases, the chloroplast enzyme ChSI does not possess any 5'-->3' exonuclease activity on double-stranded DNA. Therefore, we conclude that ChSI is a 5' flap structure-specific endonuclease with nucleolytic activity toward single-stranded substrates. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|