Tokunaga Hiroko, Arakawa Tsutomu, Tokunaga Masao
Applied and Molecular Microbiology, Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.
Protein Pept Lett. 2013 Jul 1;20(7):836-41. doi: 10.2174/0929866511320070015.
One of the hallmarks of halophilic properties is reversibility of thermal unfolding. A nucleoside diphosphate kinase (NDK) from a moderate halophile Halomonas sp. 593 (HaNDK) follows this behavior. His-tagged chimeric NDK (HisPaHaNDK) consisting of an N-terminal half of a non-halophilic Pseuodomonas aeruginosa NDK (PaNDK) and a Cterminal half of HaNDK loses this reversible property, indicating a critical role of the N-terminal portion of PaNDK in determining the reversibility of the chimeric protein. Various mutations were introduced at Arg45 and Lys61, based on the model NDK structure. It appears that having Glu at position 45 is critical in conferring the thermal reversibility to HisPa- HaNDK chimeric protein.
嗜盐特性的一个标志是热解折叠的可逆性。来自中度嗜盐菌嗜盐单胞菌属593（HaNDK）的核苷二磷酸激酶（NDK）就具有这种特性。由非嗜盐性铜绿假单胞菌NDK（PaNDK）的N端一半和HaNDK的C端一半组成的His标签嵌合NDK（HisPaHaNDK）失去了这种可逆特性，这表明PaNDK的N端部分在决定嵌合蛋白的可逆性方面起着关键作用。基于模型NDK结构，在Arg45和Lys61处引入了各种突变。似乎在位置45处具有Glu对于赋予HisPa-HaNDK嵌合蛋白热可逆性至关重要。
