Mikkelsen Nils E, Munch-Petersen Birgitte, Eklund Hans
Department of Molecular Biology, Swedish University of Agricultural Sciences, Biomedical Center, Uppsala, Sweden.
FEBS J. 2008 May;275(9):2151-60. doi: 10.1111/j.1742-4658.2008.06369.x. Epub 2008 Apr 1.
The Drosophila melanogaster multisubstrate deoxyribonucleoside kinase (dNK; EC 2.7.1.145) has a high turnover rate and a wide substrate range that makes it a very good candidate for gene therapy. This concept is based on introducing a suicide gene into malignant cells in order to activate a prodrug that eventually may kill the cell. To be able to optimize the function of dNK, it is vital to have structural information of dNK complexes. In this study we present crystal structures of dNK complexed with four different nucleoside analogs (floxuridine, brivudine, zidovudine and zalcitabine) and relate them to the binding of substrate and feedback inhibitors. dCTP and dGTP bind with the base in the substrate site, similarly to the binding of the feedback inhibitor dTTP. All nucleoside analogs investigated bound in a manner similar to that of the pyrimidine substrates, with many interactions in common. In contrast, the base of dGTP adopted a syn-conformation to adapt to the available space of the active site.
黑腹果蝇多底物脱氧核糖核苷激酶（dNK；EC 2.7.1.145）具有高周转率和广泛的底物范围，这使其成为基因治疗的一个非常好的候选者。这个概念基于将一个自杀基因引入恶性细胞中，以激活一种最终可能杀死细胞的前体药物。为了能够优化dNK的功能，获得dNK复合物的结构信息至关重要。在这项研究中，我们展示了dNK与四种不同核苷类似物（氟尿苷、溴夫定、齐多夫定和扎西他滨）复合的晶体结构，并将它们与底物和反馈抑制剂的结合相关联。dCTP和dGTP与底物位点中的碱基结合，类似于反馈抑制剂dTTP的结合方式。所有研究的核苷类似物都以类似于嘧啶底物的方式结合，有许多共同的相互作用。相比之下，dGTP的碱基采取了顺式构象以适应活性位点的可用空间。
