Characterization of a γ-radiation-induced decomposition product of thymidine. Crystal and molecular structure of the (−) cis (5 R ,6 S ) thymidine glycol
1987; NRC Research Press; Volume: 65; Issue: 11 Linguagem: Inglês
10.1139/v87-432
ISSN1480-3291
AutoresFrank E. Hruska, Rudy Sebastian, André Grand, L. Voituriez, Jean Cadet,
Tópico(s)DNA and Nucleic Acid Chemistry
ResumoX-ray crystallography was used to determine the structure of (−)cis(5R,6S)-5,6-dihydroxy-5,6-dihydrothymidine, a γ-radiation induced product of thymidine. The crystals belong to the orthorhombic space group P2 1 2 1 2 1 and have cell dimensions a = 8.420(1) Å, b = 10.422(1) Å, and 13.552(1) Å. The half-chair pucker of the 5,6-saturated pyrimidine ring is similar to that observed for the isolated base with the cis configuration, and is described by the Cremer–Pople parameters Q = 0.48 Å, θ = 62°, and [Formula: see text]. The conformation about the N-glycosyl bond is anti; the χ angle (−111.6(5)°) lies at one extreme of the range previously seen for nucleosides (−180 to −115°). The pucker 2 T 1 of the sugar (P = 151.2°; τ m = 36.5°) contrasts with the O4′-endo type of pucker seen in 5,6-dihydrothymidine ( 0 T 4 ) and (5S)-5-hydroxy-5,6-dihydrothymidine ( 0 T 1 ). The conformation about the C4′—C5′ bond is gauche + . The solid state structure is similar to that determined in aqueous solution by 1 H nmr.
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