Base pairing and mutagenesis

Observation of a protonated base pair between 2-aminopurine and cytosine in an oligonucleotide by proton NMR

Lawrence Sowers, G. V. Fazakerley, R. Eritja, B. E. Kaplan, M. F. Goodman

Research output: Contribution to journalArticle

201 Citations (Scopus)

Abstract

2-Aminopurine (AP), a potent mutagenic base analogue, most frequently pairs with thymine. In the AP·T base pair, both bases adopt normal tautomeric forms. The mechanism for the mutagenic activity arises from its observed pairing with cytosine, which has been ascribed to an enhanced tendency to adopt the rare imino tautomeric form. NMR studies in H2O on all the exchangeable protons in an oligonucleotide duplex containing an AP·T base pair show Watson-Crick hydrogen bonding. When the thymine is replaced by cytosine in the duplex, we observe an AP·C base pair. Both amino protons of AP are seen excluding the rare tautomeric form. Although several alternative structures are possible, it is shown that the second hydrogen bond is formed by protonation of the AP·C base pair and that this is the dominant species under physiological conditions.

Original languageEnglish (US)
Pages (from-to)5434-5438
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume83
Issue number15
DOIs
StatePublished - 1986
Externally publishedYes

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2-Aminopurine
Cytosine
Oligonucleotides
Mutagenesis
Base Pairing
Protons
Observation
Thymine
Hydrogen Bonding
Hydrogen

ASJC Scopus subject areas

  • Genetics
  • General

Cite this

Base pairing and mutagenesis : Observation of a protonated base pair between 2-aminopurine and cytosine in an oligonucleotide by proton NMR. / Sowers, Lawrence; Fazakerley, G. V.; Eritja, R.; Kaplan, B. E.; Goodman, M. F.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 83, No. 15, 1986, p. 5434-5438.

Research output: Contribution to journalArticle

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