Abstract: Toward the expansion of the genetic alphabet, an unnatural base pair between 7-(2-thienyl)imidazo[4,5-b]pyridine (Ds) and pyrrole-2-carbaldehyde (Pa) functions as a third base pair in replication and transcription, and provides a useful tool for the site-specific, enzymatic incorporation of functional components into nucleic acids. We have synthesized several modified-Pa substrates, such as alkylamino-, biotin-, TAMRA-, FAM-, and digoxigenin-linked PaTPs, and examined their transcription by T7 RNA polymerase using Ds-containing DNA templates with various sequences. The Pa substrates modified with relatively small functional groups, such as alkylamino and biotin, were efficiently incorporated into RNA transcripts at the internal positions, except for those less than 10 bases from the 3′-terminus. We found that the efficient incorporation into a position close to the 3′-terminus of a transcript depended on the natural base contexts neighboring the unnatural base, and that pyrimidine-Ds-pyrimidine sequences in templates were generally favorable, relative to purine-Ds-purine sequences. The unnatural base pair transcription system provides a method for the site-specific functionalization of large RNA molecules.
This is an open access article distributed under the
Creative Commons Attribution License which permits unrestricted use, distribution,
and reproduction in any medium, provided the original work is properly cited.
Export to BibTeX
MDPI and ACS Style
Morohashi, N.; Kimoto, M.; Sato, A.; Kawai, R.; Hirao, I. Site-Specific Incorporation of Functional Components into RNA by an Unnatural Base Pair Transcription System. Molecules 2012, 17, 2855-2876.
Morohashi N, Kimoto M, Sato A, Kawai R, Hirao I. Site-Specific Incorporation of Functional Components into RNA by an Unnatural Base Pair Transcription System. Molecules. 2012; 17(3):2855-2876.
Morohashi, Nobuyuki; Kimoto, Michiko; Sato, Akira; Kawai, Rie; Hirao, Ichiro. 2012. "Site-Specific Incorporation of Functional Components into RNA by an Unnatural Base Pair Transcription System." Molecules 17, no. 3: 2855-2876.