8VGD

Complex of ExbD with D-box peptide: Tetragonal form

Summary for 8VGD

• Entry DOI: 10.2210/pdb8vgd/pdb
• Related: 8VGC
• Descriptor: Biopolymer transport protein ExbD, GLN-PRO-ILE-SER-VAL-THR-MET-VAL-THR (3 entities in total)
• Functional Keywords: tonb, tonb-dependent transport, bacterial motor, transport protein
• Biological source: Escherichia coli; More
• Total number of polymer chains: 3
• Total formula weight: 19452.34

Authors

Loll, P.J. (deposition date: 2023-12-27, release date: 2024-02-14, Last modification date: 2024-03-13)

Primary citation

Loll, P.J.,Grasty, K.C.,Shultis, D.D.,Guzman, N.J.,Wiener, M.C.
Discovery and structural characterization of the D-box, a conserved TonB motif that couples an inner-membrane motor to outer-membrane transport.
J.Biol.Chem., 300:105723-105723, 2024

PubMed Abstract: Gram-negative bacteria use TonB-dependent transport to take up nutrients from the external environment, employing the Ton complex to import a variety of nutrients that are either scarce or too large to cross the outer membrane unaided. The Ton complex contains an inner-membrane motor (ExbBD) that generates force, as well as nutrient-specific transport proteins on the outer membrane. These two components are coupled by TonB, which transmits the force from the inner to the outer membrane. TonB contains an N-terminus anchored in the inner membrane, a C-terminal domain that binds the outer-membrane transporter, and a proline-rich linker connecting the two. While much is known about the interaction between TonB and outer-membrane transporters, the critical interface between TonB and ExbBD is less well understood. Here, we identify a conserved motif within TonB that we term the D-box, which serves as an attachment point for ExbD. We characterize the interaction between ExbD and the D-box both functionally and structurally, showing that a homodimer of ExbD captures one copy of the D-box peptide via beta-strand recruitment. We additionally show that both the D-box motif and ExbD are conserved in a range of Gram-negative bacteria, including members of the ESKAPE group of pathogens. The ExbD:D-box interaction is likely to represent an important aspect of force transduction between the inner and outer membranes. Given that TonB-dependent transport is an important contributor to virulence, this interaction is an intriguing potential target for novel antibacterial therapies.

PubMed: 38311172
DOI: 10.1016/j.jbc.2024.105723

Experimental method

X-RAY DIFFRACTION (1.42 Å)