6I97

Structure of the ferrioxamine B transporter FoxA from Pseudomonas aeruginosa in complex with ferrioxamine B and a C-terminal TonB fragment

Summary for 6I97

• Entry DOI: 10.2210/pdb6i97/pdb
• Descriptor: TonB-dependent receptor, Protein TonB, Ferrioxamine B (3 entities in total)
• Functional Keywords: outer membrane protein iron uptake, membrane protein
• Biological source: Pseudomonas aeruginosa; More
• Total number of polymer chains: 4
• Total formula weight: 192036.20

Authors

Josts, I.,Tidow, H. (deposition date: 2018-11-22, release date: 2019-08-28, Last modification date: 2024-11-06)

Primary citation

Josts, I.,Veith, K.,Tidow, H.
Ternary structure of the outer membrane transporter FoxA with resolved signalling domain provides insights into TonB-mediated siderophore uptake.
Elife, 8:-, 2019

PubMed Abstract: Many microbes and fungi acquire the essential ion Fe through the synthesis and secretion of high-affinity chelators termed siderophores. In Gram-negative bacteria, these ferric-siderophore complexes are actively taken up using highly specific TonB-dependent transporters (TBDTs) located in the outer bacterial membrane (OM). However, the detailed mechanism of how the inner-membrane protein TonB connects to the transporters in the OM as well as the interplay between siderophore- and TonB-binding to the transporter is still poorly understood. Here, we present three crystal structures of the TBDT FoxA from (containing a signalling domain) in complex with the siderophore ferrioxamine B and TonB and combine them with a detailed analysis of binding constants. The structures show that both siderophore and TonB-binding is required to form a translocation-competent state of the FoxA transporter in a two-step TonB-binding mechanism. The complex structure also indicates how TonB-binding influences the orientation of the signalling domain.

PubMed: 31385808
DOI: 10.7554/eLife.48528

Experimental method

X-RAY DIFFRACTION (3.35 Å)