Updated model for the complete lambda N-mediated antitermination complex, illustrating all known protein-protein, protein-RNA interactions. Nus factors B (blue) and E (wheat) cooperatively bind BoxA and BoxB, lambda N protein (gray) binds BoxB, and also possibly NusE. Lambda N protein binds RNA polymerase (RNAP) near the transcription bubble. NusA (red) stabilizes these interactions by interacting with the lambda nut spacer RNA between BoxA and BoxB, and with lambda N protein through NusA SKK (S1-KH1-KH2) and AR1 domains, respectively, while anchoring the complex to RNAP through the NusA NTD and AR2 domains. NusG (green) further stabilizes the complex through its CTD interaction with NusE, also serving as an anchor to RNAP through its NTD (Stagno, Altieri, Bubunenko, Tarasov, Court, Byrd, and Ji. Nucl. Acids Res. June 7, 2011; Full Text).