FIGURE 7.
Activities of the single Cys derivatives of NusA and λ N. A and B, locations of the cysteines on the homology model of E. coli NusA and the structure of N (34–40) peptide (green thread) complexed with AR1 dimer (PDB code 1U9L). A part of NusA-NTD is shown as space-filled to highlight the concave and convex curvatures. Space-fill models also revealed that Cys residues are surface-exposed. In vitro transcription antitermination assays at Rho-independent TR′ (C) and Rho-dependent λtR1 (D) terminators with different combinations of NusA and N derivatives are shown. 50 nm Rho was added to all the lanes except the left-most lane. DNA templates and reaction conditions were the same as described in Fig. 4. %RT in C was calculated as ([RO]/{[RO] + [TR′]}) and that in D as ([RO]/{[RO] + [all the terminated transcripts]}).