A TonB-like protein and a novel membrane protein containing an ATP-binding cassette function together in exotoxin secretion

Molecular Microbiology
S P HowardR Jahagirdar

Abstract

Protein secretion by many Gram-negative bacteria occurs via the type II pathway involving translocation across the cytoplasmic and outer membranes in separate steps. The mechanism by which metabolic energy is supplied to the translocation across the outer membrane is unknown. Here we show that two Aeromonas hydrophila inner membrane proteins, ExeA and ExeB, are required for this process. ExeB bears sequence as well as topological similarity to TonB, a protein which opens gated ports for the inward translocation of ligands across the outer membrane. ExeA is a novel membrane protein which contains a consensus ATP-binding site. Mutations in this site dramatically decreased the rate of secretion of the toxin aerolysin from the cell. ExeB was stable when overproduced in the presence of ExeA, but was degraded when synthesized in its absence, indicating that the two proteins form a complex. These results suggest that ExeA and ExeB may act together to transduce metabolic energy to the opening of a secretion port in the outer membrane.

Citations

Nov 25, 2004·Progress in Biophysics and Molecular Biology·Michael W Parker, Susanne C Feil
Oct 12, 2001·Toxicon : Official Journal of the International Society on Toxinology·M FivazF G van der Goot
Mar 27, 1998·Molecular Microbiology·O FrancetićA P Pugsley
Mar 7, 2012·The Journal of Biological Chemistry·Lay-Sun MaErh-Min Lai
May 12, 2001·Infection and Immunity·M Sandkvist
Dec 1, 2004·Proceedings of the National Academy of Sciences of the United States of America·Eric Cascales, Peter J Christie
Jun 12, 2013·Biochimica Et Biophysica Acta·Shu XuMingguo Zhou
Jan 12, 2007·Canadian Journal of Microbiology·Hyesuk KongJohn Lydon
Apr 20, 2001·Molecular Microbiology·M Sandkvist
Aug 12, 2005·Molecular Membrane Biology·Peter J Christie, Eric Cascales

❮ Previous
Next ❯

Related Concepts

Related Feeds

Bacterial Respiration

This feed focuses on cellular respiration in bacteria, known as bacterial respiration. Discover the latest research here.