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Formation of oligonucleotide-PNA-chimeras by template-directed ligationDNA sequences have previously been reported to act as templates for the synthesis of PNA, and vice versa. A continuous evolutionary transition from an informational replicating system based on one polymer to a system based on the other would be facilitated if it were possible to form chimeras, that is molecules that contain monomers of both types. Here we show that ligation to form chimeras proceeds efficiently both on PNA and on DNA templates. The efficiency of ligation is primarily determined by the number of backbone bonds at the ligation site and the relative orientation of template and substrate strands. The most efficient reactions result in the formation of chimeras with ligation junctions resembling the structures of the backbones of PNA and DNA and with antiparallel alignment of both components of the chimera with the template, that is, ligations involving formation of 3'-phosphoramidate and 5'-ester bonds. However, double helices involving PNA are stable both with antiparallel and parallel orientation of the two strands. Ligation on PNA but not on DNA templates is, therefore, sometimes possible on templates with reversed orientation. The relevance of these findings to discussions of possible transitions between genetic systems is discussed.
Document ID
20040089179
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Koppitz, M.
(Pharmaceutical Chemistry Department IV Schering AG, Berlin, Germany)
Nielsen, P. E.
Orgel, L. E.
Bada, J. L.
Date Acquired
August 21, 2013
Publication Date
January 1, 1998
Publication Information
Publication: Journal of the American Chemical Society
Volume: 120
Issue: 19
ISSN: 0002-7863
Subject Category
Exobiology
Funding Number(s)
CONTRACT_GRANT: NAGW-1660
CONTRACT_GRANT: NAGW-2881
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Exobiology
Non-NASA Center

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