Fig. 4.

Effect of ionic strength on the Ffh–FtsY complex assembly kinetics in the presence (A) or absence (B) of the SRP RNA, determined using the FRET assay. All the reactions also contain 50 mM K⁺ and 2 mM Mg²⁺, therefore, the ionic strength was increased from 50 to 250 mM. The complex assembly rate constants were obtained from the data in Fig. S4.