> I wonder if the new letters change the molecular structure overall. Do these molecules bend and twist like vanilla DNA does? Expanded genetic systems are mos

> I wonder if the new letters change the molecular structure overall. Do these molecules bend and twist like vanilla DNA does? Expanded genetic systems are most likely to work with natural enzymes if the added nucleotides pair with geometries that are similar to those displayed by standard duplex DNA. Here, we present crystal structures of 16-mer duplexes showing this to be the case with two nonstandard nucleobases (Z and P) https://www.ncbi.nlm.nih.gov/pubmed/25961938 https://www.ncbi.nlm.nih.gov/pubmed/25961938 > Can any of the new letters be methylated? Z has an amine group where the methylation would go on cytosine, and P has a ketone group instead of the amine group where the methylation would go on adenine, so presumably not, or at least not in the same way.