TonB

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TonB is involved in the uptake of iron as a component of the TonB/ExbB/ExbD complex of the Ton system.

Contents 1 Structure 2 Function 3 Regulation 4 References

Structure

TonB and ExbD bind to ExbB in a protein complex that prevents the degradation of the TonB protein. TonB and ExbD are anchored to the cytoplasmic membrane via their N-terminal hydrophobic sequences, with the rest of the protein complex extending into the periplasmic space, allowing for interaction with outer membrane proteins.^[1]

TonB complexes with BtuB in order to aid the transport of nutrients across the outer membrane by incorporating the proton-motive force into the outer membrane (see BtuB-TonB Complex).^[2]

Function

The activity of TonB is determined by the presence of ExbB and ExbD. ^[1]

Regulation

References

1. ↑ ^{1.0 1.1} Kampfenkel K, Braun V. Topology of the ExbB protein in the cytoplasmic membrane of Escherichia coli. J Biol Chem. 1993 Mar 15;268(8):6050-7. PMID:8449962
2. ↑ Shultis DD, Purdy MD, Banchs CN, Wiener MC. Outer membrane active transport: structure of the BtuB:TonB complex. Science. 2006 Jun 2;312(5778):1396-9. PMID:16741124 doi:312/5778/1396