Practice question

NusA is essential elongation factor universally conserved associating with RNA polymerase via interaction with β-flap tip helix and α-CTD as well as nascent RNA exit channel. It increases dwell time at pause sites, enhances formation terminal hairpin structures, and stimulates Rho-independent and Rho-dependent termination by stabilizing paused elongation complex and promoting RNA folding kinetics favoring terminator over antiterminator conformations. NusA also modulates attenuation in trp and his operons and interacts with λ N antitermination complex. Rather than initiating transcription or melting promoter, primary functional impact lies in pausing and termination stimulation regulating transcriptional polarity.