| Summary: | <p>Abstract</p> <p>Background</p> <p>How DNA repair enzymes find the relatively rare sites of damage is not known in great detail. Recent experiments and molecular data suggest that individual repair enzymes do <it>not </it>work independently of each other, but interact with each other through charges exchanged along the DNA. A damaged site in the DNA hinders this exchange. The hypothesis is that the charge exchange quickly liberates the repair enzymes from error-free stretches of DNA. In this way, the sites of damage are located more quickly; but how much more quickly is not known, nor is it known whether the charge exchange mechanism has other observable consequences.</p> <p>Results</p> <p>Here the size of the speed-up gained from this charge exchange mechanism is calculated and the characteristic length and time scales are identified. In particular, for <it>Escherichia coli</it>, I estimate the speed-up is 50000/<it>N</it>, where <it>N </it>is the number of repair enzymes participating in the charge exchange mechanism. Even though <it>N </it>is not exactly known, a speed-up of order 10 is not entirely unreasonable. Furthermore, upon over expression of all the repair enzymes, the location time only varies as <it>N</it><sup>-1/2 </sup>and not as 1/<it>N</it>.</p> <p>Conclusion</p> <p>The revolutionary hypothesis that DNA repair enzymes use charge exchange along DNA to locate damaged sites more efficiently is actually sound from a purely theoretical point of view. Furthermore, the predicted collective behavior of the location time is important in assessing the impact of stress-ful and radioactive environments on individual cell mutation rates.</p>
|
|---|
