Proton magnetic resonance studies of 9-(β-d-xylofuranosyl)adenine 3′,5′-cyclic monophosphate and 9-(β-d-arabinofuranosyl)adenine 2′,5′-cyclic monophosphate
1978; Elsevier BV; Volume: 62; Issue: 2 Linguagem: Inglês
10.1016/s0008-6215(00)80867-8
ISSN1873-426X
AutoresMalcolm MacCoss, Fouad S. Ezra, M. J. ROBINS, S. Danyluk,
Tópico(s)DNA and Nucleic Acid Chemistry
ResumoA detailed 1H 220-MHz n.m.r. study of 9-(β-d-xylofuranosyl)adenine 3′,5′-cyclic monophosphate (3′,5′-xylo-cAMP, 1) and 9-(∇-d-arabinofuranosyl)adenine 2′,5′-cyclic monophosphate (2′,5′-ara-cAMP, 2) in D2O solution is described. The sugar-ring conformations in 1 and 2 are shown to be 3E and 2E, respectively, and the phosphate rings are in a chair form. An unusual 4JP,H coupling of 2.4 Hz is observed between H-4′ and phosphorus in 1 and a vicinal JP,H of 30.8 Hz between H-5′ and phosphorus in 2. This latter coupling verifies a similar value found previously in the ara-cytidine analog of 2. A comparison of the conformational properties of cyclic nucleotides having fused phosphate and sugar rings has been made, together with an assessment of the use of the Karplus constants in such ring-systems.
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