Molecular weight (M) of ComA, RapF, RapF-ComA, and RapF-PhrF complexes determined by size exclusion chromatography (SEC) and analytical ultracentrifugation (AUC).

aThe SEC data represent an average of measurements obtained from two independent experiments and were determined as described in Materials and Methods.bThe AUC data represent the molecular weight determined from the linear fit applied to the ln absorbance (285 nm or 286 nm, as indicated) versus the radius squared (not shown) of the data presented in Figure 5B and 5D. N.D, not determined.