The complex of ferric-enterobactin with its transporter from Pseudomonas aeruginosa suggests a two-site model.
Moynié L, Milenkovic S, Mislin GLA, Gasser V, Malloci G, Baco E, McCaughan RP, Page MGP, Schalk IJ, Ceccarelli M, et al. Nat Commun. 2019 Aug 14; 10(1):3673. Epub 2019 Aug 14.