Figure 2.

RNA binding by NusA in the presence of α is sequence-specific and sensitive to a mutation in the S1 domain of NusA. (A) RNA binding by NusA in the presence of α is prevented by a mutation in the boxA portion of the nut site. Reactions containing wild-type or mutant ³²P-labeled nut-site RNA (as indicated) and various combinations of 10 μM α and 14 μM NusA (as indicated) were electrophoresed on 7.5% nondenaturing gels, dried, and exposed to film. (B) RNA binding by NusA in the presence of α is prevented by a mutation in the S1 domain of NusA. Reactions containing ³²P-labeled nut-site RNA and various combinations of 14 μM NusA, 14 μM NusA (amino acids 1–416), or 12 μM NusA R199A and 11 μM α (as indicated) were electrophoresed on 7.5% nondenaturing gels, dried, and exposed to film.