Expanded Genetic Alphabets: Managing Nucleotides That Lack Tautomeric, Protonated, or Deprotonated Versions Complementary to Natural Nucleotides

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• 作者：Christian B. Winiger ; Ryan W. Shaw ; Myong-Jung Kim ; Jennifer D. Moses ; Mariko F. Matsuura ; Steven A. Benner
• 刊名：ACS Synthetic Biology
• 出版年：2017
• 出版时间：February 17, 2017
• 年：2017
• 卷：6
• 期：2
• 页码：194-200
• 全文大小：374K
• ISSN：2161-5063

文摘

2,4-Diaminopyrimidine (trivially K) and imidazo[1,2-a]-1,3,5-triazine-2(8H)-4(3H)-dione (trivially X) form a nucleobase pair with Watson–Crick geometry as part of an artificially expanded genetic information system (AEGIS). Neither K nor X can form a Watson−Crick pair with any natural nucleobase. Further, neither K nor X has an accessible tautomeric form or a protonated/deprotonated state that can form a Watson−Crick pair with any natural nucleobase. In vitro experiments show how DNA polymerase I from E. coli manages replication of DNA templates with one K:X pair, but fails with templates containing two adjacent K:X pairs. In analogous in vivo experiments, E. coli lacking dKTP/dXTP cannot rescue chloramphenicol resistance from a plasmid containing two adjacent K:X pairs. These studies identify bacteria able to serve as selection environments for engineering cells that replicate AEGIS pairs that lack forms that are Watson−Crick complementary to any natural nucleobase.