Madrid O, Martín D, Atencia E A, Sillero A, Günther Sillero M A
Departamento de Bioquímica, Instituto de Investigaciones Biomédicas, CSIC, Facultad de Medicina, Universidad Autónoma de Madrid, Spain.
FEBS Lett. 1998 Aug 21;433(3):283-6. doi: 10.1016/s0014-5793(98)00932-6.
T4 DNA ligase (EC 6.5.1.1), one of the most widely used enzymes in genetic engineering, transfers AMP from the E-AMP complex to tripolyphosphate, ADP, ATP, GTP or dATP producing p4A, Ap3A, Ap4A, Ap4G and Ap4dA, respectively. Nicked DNA competes very effectively with GTP for the synthesis of Ap4G and, conversely, tripolyphosphate (or GTP) inhibits the ligation of DNA by the ligase. As T4 DNA ligase has similar requirements for ATP as the mammalian DNA ligase(s), the latter enzyme(s) could also synthesize dinucleoside polyphosphates. The present report may be related to the recent finding that human Fhit (fragile histidine triad) protein, encoded by the FHIT putative tumor suppressor gene, is a typical dinucleoside 5',5''-P1,P3-triphosphate (Ap3A) hydrolase (EC 3.6.1.29).
T4 DNA连接酶（EC 6.5.1.1）是基因工程中使用最广泛的酶之一，它将E-AMP复合物中的AMP分别转移至三聚磷酸、ADP、ATP、GTP或dATP上，生成p4A、Ap3A、Ap4A、Ap4G和Ap4dA。切口DNA与GTP在合成Ap4G的过程中竞争非常有效，相反，三聚磷酸（或GTP）会抑制连接酶对DNA的连接。由于T4 DNA连接酶对ATP的需求与哺乳动物DNA连接酶相似，后者也可能合成二核苷多磷酸。本报告可能与最近的一项发现有关，即由FHIT假定肿瘤抑制基因编码的人类Fhit（脆性组氨酸三联体）蛋白是一种典型的二核苷5',5''-P1,P3-三磷酸（Ap3A）水解酶（EC 3.6.1.29）。
