Varga Balázs, Barabás Orsolya, Kovári Júlia, Tóth Judit, Hunyadi-Gulyás Eva, Klement Eva, Medzihradszky Katalin F, Tölgyesi Ferenc, Fidy Judit, Vértessy Beáta G
Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, Budapest, Hungary.
FEBS Lett. 2007 Oct 2;581(24):4783-8. doi: 10.1016/j.febslet.2007.09.005. Epub 2007 Sep 12.
Human dUTPase, essential for DNA integrity, is an important survival factor for cancer cells. We determined the crystal structure of the enzyme:alpha,beta-imino-dUTP:Mg complex and performed equilibrium binding experiments in solution. Ordering of the C-terminus upon the active site induces close juxtaposition of the incoming nucleophile attacker water oxygen and the alpha-phosphorus of the substrate, decreasing their distance below the van der Waals limit. Complex interactions of the C-terminus with both substrate and product were observed via a specifically designed tryptophan sensor, suitable for further detailed kinetic and ligand binding studies. Results explain the key functional role of the C-terminus.
人源dUTPase对DNA完整性至关重要，是癌细胞的重要生存因子。我们确定了该酶：α,β-亚氨基-dUTP:Mg复合物的晶体结构，并在溶液中进行了平衡结合实验。活性位点上C末端的有序排列导致进入的亲核攻击水分子氧与底物的α-磷紧密并列，使其距离减小至范德华极限以下。通过专门设计的色氨酸传感器观察到C末端与底物和产物的复杂相互作用，适用于进一步详细的动力学和配体结合研究。结果解释了C末端的关键功能作用。
