DNaM
dNaM is an artificial nucleoside containing a 3-methoxy-2-naphthyl group instead of a base.
When it was originally successfully introduced into DNA, it was paired up with dTPT3. For short it is called X whilst the dTPT3 being called Y. dTPT3 was replaced by d5SICS in revised versions. It pairs with d5SICS in a hydrophobic interaction. It was not able to be removed by the error-correcting machinery of the E. coli into which it was inserted. While the E. coli managed to hold onto the new base for a short period and even reproduce, it eventually rejected it. The pairing of d5SICS–dNaM is mediated by packing and hydrophobic forces instead of hydrogen bonding, which occurs in natural base pairs. Therefore, in free DNA, rings of d5SICS and dNaM are placed in parallel planes instead of the same plane.
