Fig. 4. Co-translational targeting of Momp2 RNCs to SecY, which is mediated by SRP. (A) Nascent chains of MtlA and Momp2 of the indicated lengths were synthesized in vitro (cf. Figure 1) in the presence of the endogenous amounts of SecA, SecB, F1-ATPase, Ffh and FtsY. When indicated, inside-out inner membrane vesicles (INVs) were present during synthesis and samples were treated post-translationally with DSS. Immunoprecipitation of the samples in the even-numbered lanes using anti-SecY polyclonal antibodies is shown below. (B) RNCs of Momp2-301 were synthesized in vitro in the presence of the indicated components. Nascent chains in lane 7 were treated with 0.8 mM puromycin for 10 min at 37°C before immunoprecipitation.