MECHANISMS OF TONB-CATALYZED IRON TRANSPORT THROUGH THE ENTERIC BACTERIAL-CELL ENVELOPE

The recent solution of enteric bacterial porin structure, and new insi ghts into the mechanism by which outer membrane receptor proteins reco gnize and internalize specific ligands, advocates the re-evaluation of TonB-dependent transport physiology. In this minireview we discuss th e potential structural features of siderophore receptors and TonB, and use this analysis to evaluate both existing and new models of energy and signal transduction from the inner membrane to the outer membrane of gram-negative bacteria.