The AlkB enzyme is an Fe(II)- and α-ketoglutarate-dependent dioxygenase that repairs DNA alkyl lesions by a direct reversal of damage mechanism as part of the adaptive response in E. coli. The reported substrate scope of AlkB includes simple DNA alkyl adducts, such as 1-methyladenine, 3-methylcytosine, 3-ethylcytosine, 1-methylguanine, 3-methylthymine, and N(6)-methyladenine, as well as more co...

Sketch of Proof: By examining the distance of the elements to be exchanged, one deduces that the prefix reversal of size (3 / 4)n creates the maximum distance between images, because the individual elements to be exchanged are then the furthest distance from each other. We measure the distance from