Shibata Rie, Bessho Yoshitaka, Shinkai Akeo, Nishimoto Madoka, Fusatomi Emiko, Terada Takaho, Shirouzu Mikako, Yokoyama Shigeyuki
RIKEN Genomic Sciences Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan.
Biochem Biophys Res Commun. 2007 Mar 30;355(1):122-8. doi: 10.1016/j.bbrc.2007.01.119. Epub 2007 Jan 31.
The transcription factor NusA functions in transcriptional regulation involving termination in bacteria. A NusA homolog consisting of only the two KH domains is widely conserved in archaea, but its function remains unknown. We have found that Aeropyrum pernix NusA strongly binds to a certain CU-rich sequence near a termination signal. Our crystal structure of A. pernix NusA revealed that its spatial arrangement is quite similar to that of the KH domains of bacterial NusA. Thus, we consider archaeal NusA to have retained some functions of bacterial NusA, including the ssRNA-binding ability. Remarkable structural differences between archaeal and bacterial NusA exist at the interface with RNAP, in connection with the different NusA-binding sites around the termination signals. Transcriptional termination in archaea could differ from all of the known bacterial and eukaryal mechanisms, in terms of the combination of a bacterial factor and a eukaryal-type RNAP.
转录因子NusA在细菌转录调控（包括终止过程）中发挥作用。一种仅由两个KH结构域组成的NusA同源物在古菌中广泛保守，但其功能仍不清楚。我们发现，嗜热栖热放线菌NusA与终止信号附近的某个富含CU的序列强烈结合。我们解析的嗜热栖热放线菌NusA晶体结构表明，其空间排列与细菌NusA的KH结构域非常相似。因此，我们认为古菌NusA保留了细菌NusA的一些功能，包括单链RNA结合能力。古菌和细菌NusA在与RNA聚合酶（RNAP）的界面处存在显著的结构差异，这与终止信号周围不同的NusA结合位点有关。就细菌因子和真核生物型RNAP的组合而言，古菌中的转录终止可能不同于所有已知的细菌和真核生物机制。
