How DNA repair enzymes find the relatively rare sites of damage is not known in great detail. Recent experiments and molecular data suggest that the individual repair enzymes do not work independently of each other, but rather interact with each other through currents exchanged along DNA. A damaged site in DNA hinders this exchange and this makes it possible to quickly free up resources from er...

Recently, a novel gene-deletion method was developed for the crenarchaeal model Sulfolobus islandicus, which is a suitable tool for addressing gene essentiality in depth. Using this technique, we have investigated functions of putative DNA repair genes by constructing deletion mutants and studying their phenotype. We found that this archaeon may not encode a eukarya-type of NER (nucleotide exci...

It has been discovered recently, via structural and biophysical analyses, that proteins can mimic DNA structures in order to inhibit proteins that would normally bind to DNA. Mimicry of the phosphate backbone of DNA, the hydrogen-bonding properties of the nucleotide bases and the bending and twisting of the DNA double helix are all present in the mimics discovered to date. These mimics target a...

In mammalian cells, genomic DNA is packaged with histone proteins and condensed into chromatin. To gain access to the DNA, chromatin remodelling required that enhanced through post-translational modifications, which subsequently stimulate processes including repair transcription. Histone acetylation one of most well understood modifications controlled by acetyltransferases (HATs) deacetylases (...

Direct observation of enzymes interacting with DNA should be one of the ultimate technologies for investigating the mechanical behavior of the enzymes during the reactions. Atomic force microscopy (AFM) enables observation of biomolecules at a nanoscale spatial resolution; however, for a stable analysis, a scaffold to observe the reaction should be explored. DNA origami has recently been develo...

Mex+ human lymphoma cell lines contain O6-methylguanine-DNA methyltransferase, a DNA repair enzyme that undergoes suicide inactivation on interaction with its substrate. The cells are therefore competent to remove the alkylation lesion O6-methylguanine from their DNA. However, several repair-deficient lymphoma cell lines (Mex-) are also known. It is shown here that Mex+ cells can be converted t...

As the vital information repositories of the cell, the nucleic acids DNA and RNA pose many challenges as enzyme substrates. To produce, maintain and repair DNA and RNA, and to extract the genetic information that they encode, a battery of remarkable enzymes has evolved, which includes translocases, polymerases/replicases, helicases, nucleases, topoisomerases, transposases, recombinases, repair ...

Chemical carcinogens are generally activated enzymatically to electrophiles that form covalently bound carcinogen-DNA adducts. Detoxifying enzymes are competing with the activating enzymes for these procarcinogenic chemical substrates. Wide person-to-person variations in these two types of enzymatic activities are found. Repair rates of DNA damage caused by carcinogens also vary among individua...

The response of different tumours to radiation varies. This variation has been attributed to, among others, varying DNA repair capabilities The response of three tumour lines, differing in their sensitivities to radiation, namely, murine fibrosarcoma, lymphosarcoma and ascites, was studied by following the activities of enzymes known to be involved in DNA repair. The activities of poly (ADP-rib...

New insights into the workings of the repair enzymes that police the genome for damage to DNA come from the recently determined structures of two uracil-DNA glycosylases.