Noncanonical Nucleobases

Naturally-occurring modified nucleobases, next to the four canonical nucleobases, extend the chemical information content of DNA and RNA, but their role in regulating the basic functions in a cell is still largely unexplored. In addition, over the past two decades chemically modified nucleobases have been developed as versatile tool for chemical fine-tuning of artificial DNA in the emerging area of synthetic biology. Indeed, unnatural base pairing may possess higher specificity and thermal stability through suitable design of artificial nucleobases and yield an artificially expanded genetic information system. The aim of this forthcoming Special Issue, "Noncanonical Nucleobases", is not only to present new crystal structures, but also to discuss the nature and the strength of interactions in biological systems containing such important molecules. However, theoretical analyses concerning modified nucleobases, if related to their crystal structure, are also appropriate.