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bioquest
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Are there any known enzymes that will fix oxidative dna damage without correcting mismatched bases? Any enzymes that are thought to work like that? thanks
The huge variety of DNA-reactive chemicals in our environment combined with the huge variety of alterations that can be produced by radiation and by oxidative and free radical attack on DNA can generate so many types of damage that coping with all types of damage by evolutionary development of damage-specific DNA glycosylases would be difficult if not impossible.
There was speculation in the 1950's that the number of chromosomes influenced radiosensitivity, and that insects had fewer chromosomes. There may be some truth in this speculation, as we now know that (in general) the less DNA a cell has the more resistant it is to ionizing radiation. Since DNA is the critical target for cell killing (in mammalian as well as insect cells), it is logical that the less DNA there is, the harder it is to hit. While the density of ionizations produced by X-rays is sufficient that animal size could not explain resistance, the density of ionizations is low enough that total cellular DNA content could explain resistance... So it is clear that insects are resistant to ionizing radiation and that this resistance is an inherent property of their cells. But it is not clear exactly what the basis of this cellular resistance is, although the dominant theory is that it relates to the relatively small amount of DNA in insect cells.
Michael Daly has suggested that the bacterium uses manganese as an antioxidant to protect itself against radiation damage.[10] In 2008 his team showed that high intracellular levels of manganese(II) in D. radiodurans protect proteins from being oxidized by radiation, and proposed the idea that "protein, rather than DNA, is the principal target of the biological action of [ionizing radiation] in sensitive bacteria, and extreme resistance in Mn-accumulating bacteria is based on protein protection".[11]
bioquest said:My last question on it though is, are there any theoretical way(s) that could be used now that would make it so that there would be no free radicals in the brain/any specific organ that existed long enough to do damage, that could be used in a way the mammal/brain would survive?
Also could the ability to regenerate as fast as biologically possible theoretically solve the oxidative dna damage or would cells still get oxidative dna damage?