The B–Z transition in two synthetic oligonucleotides: d(C-2-amino-ACGTG) and d(m5CGCAm5CGTGCG) studied by IR, NMR and CD spectroscopies

• Published in: Nucleic acids research Vol. 12; no. 15; pp. 6291 - 6305
• Main Authors: Taboury, J.A., Adam, S., Taillandier, E., Neumann, J.-M., Tran-Dinh, S., Huynh-Dinh, T., d'Estaintot, B.Langlois, Conti, M., Igolen, J.
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 10.08.1984
• Subjects: 5-Methylcytosine; Base Sequence; Circular Dichroism; Cytosine - analogs & derivatives; Deoxyadenosines - analogs & derivatives; Magnetic Resonance Spectroscopy; Nucleic Acid Conformation; Oligodeoxyribonucleotides; Oligonucleotides; Spectrophotometry, Infrared; Structure-Activity Relationship
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/12.15.6291

The sequences CA'CGTG (where A'=2-aminodeoxyadenosine) and m5CGCAm5CGTGCG are prepared and studied by IR, CD and 1H-NMR. Infrared spectra demonstrate the capacity of the modified hexamer and decamer to adopt a Z conformation. The influence of the NH2 substitution on the adenine or of the methylated terminal part of the decamer acting with the increase of the DNA concentration stabilizes the Z conformation at room temperature in low humidity films. Very weak proportion of Z conformation is detected in UV dilute solutions. In more concentrated NMR solutions, the Z proportion induced by high salt content is only 20–25%. The effects of the concentration and of the covalent modification of the bases are discussed.