TonB-dependent fimsbactin receptor (FbsJ) (FbsJ)

The TonB-dependent fimsbactin receptor (FbsJ) is an essential outer membrane protein in Acinetobacter baumannii that facilitates the uptake of the fimsbactin-ferric complex (Proschak et al., 2013). As a member of the TonB-dependent transporter family, it utilizes the proton motive force, transduced by the TonB-ExbB-ExbD complex, to actively transport iron-laden siderophores across the bacterial outer membrane (Runci et al., 2019). This process is critical for the survival and virulence of A. baumannii in the iron-restricted environment of a host, where free iron is sequestered by proteins like transferrin and lactoferrin (Yamamoto et al., 1994). In pharmaceutical research, this receptor is targeted using a Trojan Horse strategy, where antibiotics are chemically linked to fimsbactin or its analogs (Wencewicz, 2016). These siderophore-drug conjugates are recognized by the receptor and actively transported into the bacterium, effectively bypassing the low permeability of the outer membrane and overcoming certain resistance mechanisms in multidrug-resistant strains (Ghosh et al., 2017).

Other names

Fimsbactin receptorFimsbactin-ferric complex receptorFbsJTonB-dependent transporter of fimsbactinFerric-fimsbactin receptor

Siderophore-mediated active transport of conjugated antibiotics into the bacterial periplasm or cytoplasm