Escaffre Marine, Chottard Jean-Claude, Bombard Sophie
Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601, Université René Descartes, 45 rue des Saints-Pères, 75270 Paris cedex 06, France.
Nucleic Acids Res. 2002 Dec 1;30(23):5222-8. doi: 10.1093/nar/gkf672.
The cross-linking reaction described previously in the DNA and 2'-O-methyl RNA series is extended to RNA duplexes. A 17mer single-stranded RNA containing the 1,3-trans-[Pt(NH3)2[(GAG)-N7G,N7G]] intrastrand chelate, named GAG (* indicating a platinated base) gives, upon pairing with the complementary RNA strand, the GAG/CUC interstrand cross-link. The rate of the reaction in 200 mM NaClO4 is similar to that observed for DNA-RNA duplexes. It depends on the added Na+ or Mg2+ cation and on its concentration. RNA duplexes containing GA/GA or AG/AG tandem mismatches in the rearrangement triplet core were also studied. The major interstrand cross-links, GAG/CGA and GAG/AGC, are accompanied by a minor one involving the central G of the CGA or AGC complementary sequence GAG/CGA and GAG/AGC. In 200 mM NaClO4, the GA/GA tandem mismatch does not modify the rate of the cross-linking rearrangement whereas the AG/AG mismatch slows it down by a factor of four. Our results reflect the predominance of the local structure of the rearrangement core over the nucleophility of the cross-linking base. They also show that the reaction could be used to trap tertiary structures of naturally occurring RNAs, including those with the commonly encountered GA/GA mismatch.
先前在DNA和2'-O-甲基RNA系列中描述的交联反应扩展到了RNA双链体。一种含有1,3-反式-[Pt(NH3)2[(GAG)-N7G,N7G]]链内螯合物的17聚体单链RNA，命名为GAG（表示铂化碱基），与互补RNA链配对时，会形成GAG/CUC链间交联。在200 mM NaClO4中该反应的速率与DNA-RNA双链体的反应速率相似。它取决于添加的Na+或Mg2+阳离子及其浓度。还研究了在重排三联体核心中含有GA/GA或AG/AG串联错配的RNA双链体。主要的链间交联GAG/CGA和GAG/AGC伴随着一个次要的交联，涉及CGA或AGC互补序列的中心G，即GAG/CGA和GAG/AGC。在200 mM NaClO4中，GA/GA串联错配不会改变交联重排的速率，而AG*/AG错配会使其减慢四倍。我们的结果反映了重排核心的局部结构比交联碱基的亲核性更占优势。它们还表明，该反应可用于捕获天然RNA的三级结构，包括那些常见GA/GA错配的结构。
