Question

Deinococcus radiodurans is probably the world’s toughest bacterium (first discovered growing in ground meat that had been “sterilized” by radiation), able to withstand doses of ionizing radiation ~3000 times greater than those that are lethal to humans. It was also discovered that D. radiodurans has a particularly large number of genes that encode for DNA repair proteins and multiple (4 to 10) copies of its closed circular genome per cell. It has been hypothesized that these multiple dsDNA copies are stacked like coins with their sequences aligned. How would this spatial arrangement help D. radiodurans efficiently repair its DNA?

Answer 1

The multiple assemblies that are stacked like coins with the sequences aligned helps in efficiently repair of DNA by enhancing the speed of the reactions. The use of the proteins in the process of repair of the DNA requires protein-protein interaction that is triggered by number of post translational modifications. The stacking of the coins like sequences helps the proteins to enables the cell to shelter broken DNA. The genome produce highly compacted nucleiod structure. It helps in co-ordinated balance of phosphorylation and dephosphorylation which helps in efficient and absolutely quick repair by the ionizing radiation.