A beta strand lock exchange for signal transduction in TonB-dependent transducers on the basis of a common structural motif.
Brillet, K., Journet, L., Celia, H., Paulus, L., Stahl, A., Pattus, F., Cobessi, D.(2007) Structure 15: 1383-1391
- PubMed: 17997964 
- DOI: https://doi.org/10.1016/j.str.2007.08.013
- Primary Citation of Related Structures:  
2O5P - PubMed Abstract: 
Transport of molecules larger than 600 Da across the outer membrane involves TonB-dependent receptors and TonB-ExbB-ExbD of the inner membrane. The transport is energy consuming, and involves direct interactions between a short N-terminal sequence of receptor, called the TonB box, and TonB. We solved the structure of the ferric pyoverdine (Pvd-Fe) outer membrane receptor FpvA from Pseudomonas aeruginosa in its apo form. Structure analyses show that residues of the TonB box are in a beta strand which interacts through a mixed four-stranded beta sheet with the periplasmic signaling domain involved in interactions with an inner membrane sigma regulator. In this conformation, the TonB box cannot form a four-stranded beta sheet with TonB. The FhuA-TonB or BtuB-TonB structures show that the TonB-FpvA interactions require a conformational change which involves a beta strand lock-exchange mechanism. This mechanism is compatible with movements of the periplasmic domain deduced from crystallographic analyses of FpvA, FpvA-Pvd, and FpvA-Pvd-Fe.
Organizational Affiliation: 
Institut Gilbert-Laustriat, UMR7175 CNRS/Université Louis Pasteur, Strasbourg I, Département Récepteurs et Protéines Membranaires, Ecole Supérieure de Biotechnologie de Strasbourg, BP 10413, F-67412 Illkirch, France.