Brennan C A, Dombroski A J, Platt T
Cell. 1987 Mar 27;48(6):945-52. doi: 10.1016/0092-8674(87)90703-3.
E. coli rho factor can unwind a short RNA-DNA duplex in vitro. The duplex is formed between a polylinker sequence at the 3' end of RNA derived from the rho-dependent terminator trp t' and the complementary sequence in a single-strand DNA molecule. Release of trp t' RNA from the duplex requires nucleoside triphosphate hydrolysis by rho's NTPase activity and is dependent on rho recognition of the RNA that is 5' to the RNA-DNA duplex region. The direction of helix unwinding appears to be 5' to 3' along the RNA molecule. These characteristics now account for how the RNA-binding and RNA-dependent NTP hydrolysis activities of rho may participate directly in transcription termination. Our results suggest that NTP hydrolysis is utilized to help unwind the RNA-DNA duplex at the 3' end of a nascent transcript, facilitating RNA release from the DNA template.
大肠杆菌rho因子在体外可解开一段短的RNA-DNA双链体。该双链体是由源自rho依赖性终止子trp t'的RNA 3'端的多克隆位点序列与单链DNA分子中的互补序列形成的。从双链体中释放trp t' RNA需要rho的NTPase活性水解核苷三磷酸，并且依赖于rho对RNA-DNA双链体区域5'端RNA的识别。螺旋解旋方向似乎是沿着RNA分子从5'到3'。这些特性现在解释了rho的RNA结合和RNA依赖性NTP水解活性如何可能直接参与转录终止。我们的结果表明，利用NTP水解来帮助解开新生转录本3'端的RNA-DNA双链体，促进RNA从DNA模板上释放。
