Truscott K N, Scopes R K
School of Biochemistry, La Trobe University, Bundoora, Victoria, 3083, Australia.
Gene. 1998 Sep 14;217(1-2):15-23. doi: 10.1016/s0378-1119(98)00382-5.
The groE homologous genes of the anaerobic thermophile Thermoanaerobacter sp. Rt8.G4 (TRt) have been isolated, sequenced and analysed. The TRt groES and groEL encode subunits of chaperonin 10 (Cpn10) and chaperonin 60 (Cpn60) of 94 and 541 amino acids, respectively, and are arranged in that order forming the open reading frames (ORFs) of a bicistronic operon. A controlling inverted repeat of chaperone expression (CIRCE) element lies between the consensus promoter of the operon and TRt groES. At optimum growth temperature (65 degreesC) the chaperonins of TRt are expressed, but production of Cpn60 increases significantly following temperature increases of 3-10 degreesC. Functionally intact recombinant TRt chaperonins were produced in Escherichia coli. However, owing to codon incompatibility, replacement of consecutive AGA codons in the gene encoding TRt Cpn60 was necessary for optimum expression in this heterologous host.
已分离、测序并分析了厌氧嗜热菌嗜热栖热菌属菌株Rt8.G4（TRt）的groE同源基因。TRt groES和groEL分别编码94个和541个氨基酸的伴侣蛋白10（Cpn10）和伴侣蛋白60（Cpn60）的亚基，并按此顺序排列，形成一个双顺反子操纵子的开放阅读框（ORF）。一个伴侣蛋白表达控制反向重复（CIRCE）元件位于操纵子的共有启动子和TRt groES之间。在最佳生长温度（65℃）下，TRt的伴侣蛋白得以表达，但温度升高3-10℃后，Cpn60的产量显著增加。在大肠杆菌中产生了功能完整的重组TRt伴侣蛋白。然而，由于密码子不兼容性，为了在这种异源宿主中实现最佳表达，有必要替换编码TRt Cpn60的基因中连续的AGA密码子。
