Tokunaga Hiroko, Ishibashi Matsujiro, Arisaka Fumio, Arai Shigeki, Kuroki Ryota, Arakawa Tsutomu, Tokunaga Masao
Applied and Molecular Microbiology, Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.
FEBS Lett. 2008 Apr 2;582(7):1049-54. doi: 10.1016/j.febslet.2008.02.054. Epub 2008 Mar 3.
Halomonas nucleoside diphosphate kinase (HaNDK) forms a dimeric assembly and Pseudomonas NDK (PaNDK) forms a tetrameric assembly. The mutation of Glu134 to Ala in HaNDK resulted in the conversion of the native dimeric structure to the tetramer assembly. Conversely, the mutation of Ala134 to Glu in PaNDK lead to the conversion from the tetramer to the dimer assembly, indicating that a single amino acid substitution at position 134 results in an alteration of the oligomeric structure of NDK. By modeling the structure of HaNDK and PaNDK based on the crystal structure of Myxococcus NDK, we showed that Glu134 exerts sufficient repulsive forces to disrupt the dimer-dimer interaction and prevent the formation of the tetramer.
嗜盐单胞菌核苷二磷酸激酶（HaNDK）形成二聚体组装，而假单胞菌核苷二磷酸激酶（PaNDK）形成四聚体组装。HaNDK中Glu134突变为Ala导致天然二聚体结构转变为四聚体组装。相反，PaNDK中Ala134突变为Glu导致从四聚体转变为二聚体组装，这表明134位的单个氨基酸取代会导致核苷二磷酸激酶寡聚体结构的改变。通过基于粘球菌核苷二磷酸激酶的晶体结构对HaNDK和PaNDK的结构进行建模，我们发现Glu134施加了足够的排斥力来破坏二聚体 - 二聚体相互作用并阻止四聚体的形成。
