Heinrich T, Schröder W, Erdmann V A, Hartmann R K
Institut für Biochemie, Freie Universität Berlin, Germany.
J Bacteriol. 1992 Dec;174(23):7859-63. doi: 10.1128/jb.174.23.7859-7863.1992.
The nusG gene of Thermus thermophilus HB8 was cloned and sequenced. It is located 388 bp downstream from tufB, which is followed by the genes for ribosomal proteins L11 and L1. No equivalent to secE preceding nusG, as in Escherichia coli, could be detected. The nusG gene product was overproduced in E. coli. A rabbit antiserum raised against the purified recombinant NusG reacted exclusively with one protein band of T. thermophilus crude extracts in Western blot (immunoblot) analyses, and no cross-reaction of the antiserum with E. coli NusG was observed. Recombinant NusG and the reacting T. thermophilus wild-type protein had identical sizes on sodium dodecyl sulfate-polyacrylamide gels. T. thermophilus and E. coli NusG have 45% identical and 22.5% similar amino acids, and similarities between the two proteins are most pronounced in carboxy-terminal regions. The T. thermophilus nusG gene could not rescue a nusG-deficient E. coli mutant strain.
嗜热栖热菌HB8的nusG基因被克隆并测序。它位于tufB下游388 bp处，其后面是核糖体蛋白L11和L1的基因。在嗜热栖热菌中，未检测到如大肠杆菌中位于nusG之前的secE的对应物。nusG基因产物在大肠杆菌中过量表达。在蛋白质免疫印迹分析中，针对纯化的重组NusG产生的兔抗血清仅与嗜热栖热菌粗提物的一条蛋白带发生反应，且未观察到该抗血清与大肠杆菌NusG发生交叉反应。在十二烷基硫酸钠-聚丙烯酰胺凝胶上，重组NusG与发生反应的嗜热栖热菌野生型蛋白大小相同。嗜热栖热菌和大肠杆菌的NusG有45%的氨基酸相同，22.5%的氨基酸相似，且两种蛋白质之间的相似性在羧基末端区域最为明显。嗜热栖热菌的nusG基因无法拯救nusG缺陷的大肠杆菌突变株。
