胸苷酸-（3'-5'）-胸苷一磷酸（6-4）光加合物的杜瓦价键异构体：形成、碱不稳定性和构象性质

The Dewar valence isomer of the (6-4) photoadduct of thymidylyl-(3'-5')-thymidine monophosphate: formation, alkaline lability and conformational properties.

作者信息

Kan L S, Voituriez L, Cadet J

机构信息

Department of Biochemistry, Johns Hopkins University, Baltimore, MD 21205.

出版信息

J Photochem Photobiol B. 1992 Mar 13;12(4):339-57. doi: 10.1016/1011-1344(92)85040-2.

DOI:10.1016/1011-1344(92)85040-2

PMID:1578296

Abstract

The formation of the Dewar valence isomer of the pyrimidine(6-4)pyrimidone photoadduct of thymidylyl-(3'-5')-thymidine monophosphate (TpT) was investigated under different irradiation conditions. This photoproduct was generated on exposure of TpT to far-UV radiation. However, no detectable amount of the Dewar isomer or its precursor (pyrimidine(6-4)pyrimidone photoadduct) was observed following acetone photosensitization of TpT. The Dewar valence isomer was much more unstable than the pyrimidine(6-4)pyrimidone photoproduct when treated with hot piperidine. A detailed conformational analysis of the TpT Dewar isomer photoproduct is reported as inferred from extensive one- and two-dimensional 300 and 620 MHz proton nuclear magnetic resonance (1H NMR) measurements and molecular mechanics calculations.

摘要

在不同的辐照条件下，研究了胸苷酰基 -（3'-5'）- 胸苷一磷酸（TpT）的嘧啶（6 - 4）嘧啶酮光加合物的杜瓦价键异构体的形成。该光产物是在TpT暴露于远紫外辐射时产生的。然而，在TpT经丙酮光敏化后，未观察到可检测量的杜瓦异构体或其前体（嘧啶（6 - 4）嘧啶酮光加合物）。当用热哌啶处理时，杜瓦价键异构体比嘧啶（6 - 4）嘧啶酮光产物更不稳定。根据广泛的一维和二维300和620 MHz质子核磁共振（1H NMR）测量以及分子力学计算推断，报告了TpT杜瓦异构体光产物的详细构象分析。