Wilds Christopher J, Noronha Anne M, Robidoux Sebastien, Miller Paul S
Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada.
Nucleosides Nucleotides Nucleic Acids. 2005;24(5-7):965-9. doi: 10.1081/ncn-200059329.
DNA duplexes containing an ethyl interstrand crosslink that bridges the N3 atoms of thymidines on the opposite strands have been synthesized using an approach that combines conventional solid phase oligonucleotide synthesis and the selective removal of protecting groups of a crosslinked thymidine dimer. This approach allows for the assembly of a crosslinked duplex directly on the solid support. Duplexes that contain a N3T-ethyl-N3T interstrand crosslink in a staggered orientation at either a -TA- or -AT-step in a duplex have been prepared. When placed in an -AT- step of a duplex the effect was stabilizing relative to the non-crosslinked control duplex (deltaTm= +24 degrees C) and this crosslinked duplex was found to efficiently form multimers in the presence of T4 ligase. In the case of the -TA- crosslinked duplex the stabilizing effect was less pronounced (deltaT.= +6 degrees C) and likewise did not undergo self ligation under identical conditions. Molecular modeling studies suggested that the -AT- containing lesion had little deviation in structure relative to the non-crosslinked duplex DNA control, whereas the -TA- crosslinked duplex exhibited significant buckling of the base pairs flanking the lesion.
已采用一种将传统固相寡核苷酸合成与交联胸苷二聚体保护基团的选择性去除相结合的方法，合成了含有乙基链间交联的DNA双链体，该交联桥接了相反链上胸苷的N3原子。这种方法允许在固相载体上直接组装交联双链体。已制备出在双链体的 -TA- 或 -AT- 步处以交错取向含有N3T-乙基-N3T链间交联的双链体。当置于双链体的 -AT- 步时，相对于非交联对照双链体，其作用是稳定的（ΔTm = +24℃），并且发现这种交联双链体在T4连接酶存在下能有效地形成多聚体。对于 -TA- 交联双链体，稳定作用不太明显（ΔT = +6℃），同样在相同条件下不会发生自连接。分子建模研究表明，含 -AT- 的损伤相对于非交联双链体DNA对照在结构上几乎没有偏差，而 -TA- 交联双链体在损伤侧翼的碱基对处表现出明显的弯曲。
