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Updated: Jul 10, 2026

Production of Disulfide-stabilized Transmembrane Peptide Complexes for Structural Studies
Published on: March 6, 2013
A beta strand lock exchange for signal transduction in TonB-dependent transducers on the basis of a common structural
Karl Brillet1, Laure Journet, Hervé Célia
1Institut 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.
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.
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