Nitric oxide inhibits DNA ligase activity: potential mechanisms for NO-mediated DNA damage

Nitric oxide inhibits DNA ligase activity: potential mechanisms for NO-mediated DNA damage.

Nitric oxide-induced modifications of DNA occur either by directly altering DNA chemically through reactive nitrogen oxide species (RNOS) or indirectly by inhibiting various repair processes. DNA ligases are enzymes which rejoin single-strand breaks and are critical for DNA integrity during processes such as gene transcription and repair. The eukaryotic and T4 DNA ligases are active in the pres...

Ligase-mediated construction of branched DNA strands: a novel DNA joining activity catalyzed by T4 DNA ligase.

Branched nucleic acid strands exist as intermediates in certain biological reactions, and bifurcating DNA also presents interesting opportunities in biotechnological applications. We describe here how T4 DNA ligase can be used for efficient construction of DNA molecules having one 5' end but two distinct 3' ends that extend from the 2' and 3' carbons, respectively, of an internal nucleotide. Th...

Exogenous nitric oxide potentiate DNA damage and alter DNA repair in cells exposed to ionising radiation.

UNLABELLED The aim of this study was to investigate impact of exogenous nitric oxide (NO) on generation of different types of DNA damages, their transformation, and specificity of DNA repair in cells treated with ionizing radiation (IR). METHODS levels of single-strand and double-strand breaks assessed in peripheral blood lymphocytes (PBL) isolated from healthy humans and treated in vitro wit...

Radiation track and DNA damage

Repair mechanisms for oxidative DNA damage.

Reactive oxygen species are formed as by-products of mitochondrial aerobic respiration, as induced products upon exposure to certain environmental/exogenous agents (e.g. ionizing radiation), or as intended products during the immune response against invading foreign microbes. Although serving as essential signaling molecules in certain biological processes (e.g. during gene activation responses...