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Updated: Jul 10, 2026

Characterization of Membrane Transporters by Heterologous Expression in E. coli and Production of Membrane Vesicles
Published on: December 31, 2019
Are bacterial 'autotransporters' really transporters?
1Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Building 5, Room 201, 5 Memorial Drive, Bethesda, MD 20892-0538, USA. harris_bernstein@nih.gov
Abstract:
Autotransporters are bacterial outer membrane proteins that consist of a large N-terminal extracellular domain ('passenger domain') and a C-terminal beta-barrel domain ('beta domain'). The beta domain was originally proposed to function as a channel that transports its own passenger domain across the outer membrane. Results of recent structural, biochemical and molecular genetic studies, however, have challenged this idea. Here I describe an alternative model in which translocation of the passenger domain is mediated by an exogenous factor (possibly a newly identified factor necessary for assembly of outer membrane proteins called 'Omp85/YaeT'), whereas the beta domain only targets the protein to the outer membrane and serves as a membrane anchor.
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