Sonnemann J, Mutzel R
Fakultät für Biologie, Universität Konstanz, Germany.
Biochem Biophys Res Commun. 1995 Apr 17;209(2):490-6. doi: 10.1006/bbrc.1995.1528.
Elongation of nascent polypeptides in a Dictyostelium discoideum in vitro translation system did not require the addition of ATP and GTP when creatine phosphate and creatine phosphokinase were present. However, depletion of the exogenous energy supply completely abolished incorporation of amino acids. Addition of dTTP, a nucleoside triphosphate that can be utilized by nucleoside diphosphate kinase (NDP kinase) to phosphorylate endogenous ADP and GDP, partially restored protein synthesis. Dictyostelium ribosomes were found to contain NDP kinase activity that could not be released by 1 M KCl. Thermal denaturation studies, specific inhibition with antibodies, and Western blotting identify the activity as cytosolic NDP kinase. These data support the idea that GTP can be fed into the translation machinery efficiently by NDP kinase associated with active ribosomes.
在盘基网柄菌体外翻译系统中，当存在磷酸肌酸和肌酸磷酸激酶时，新生多肽的延伸不需要添加ATP和GTP。然而，外源性能量供应的耗尽完全消除了氨基酸的掺入。添加dTTP（一种可被核苷二磷酸激酶（NDP激酶）用于磷酸化内源性ADP和GDP的核苷三磷酸）可部分恢复蛋白质合成。发现盘基网柄菌核糖体含有不能被1 M KCl释放的NDP激酶活性。热变性研究、抗体特异性抑制和蛋白质免疫印迹分析确定该活性为胞质NDP激酶。这些数据支持这样一种观点，即与活性核糖体相关的NDP激酶可以有效地将GTP输入到翻译机制中。
