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Updated: Jul 10, 2026
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From Constructs to Crystals – Towards Structure Determination of β-barrel Outer Membrane Proteins
Published on: July 4, 2016
Functioning of outer membrane protein assembly factor Omp85 requires a single POTRA domain
Martine P Bos1, Viviane Robert, Jan Tommassen
1Department of Molecular Microbiology, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
EMBO Reports
|November 17, 2007
Summary
The Omp85 protein
Area of Science:
- Biochemistry
- Molecular Biology
- Microbiology
Background:
- Beta-barrel proteins are crucial components of outer membranes in Gram-negative bacteria, mitochondria, and chloroplasts.
- Omp85 is the central protein in the assembly machinery for beta-barrel proteins in bacteria.
Purpose of the Study:
- To investigate the functional roles of the polypeptide-transport-associated (POTRA) domains within the bacterial Omp85 protein.
- To determine the essential domains of Omp85 required for its function in Neisseria meningitidis.
Main Methods:
- Site-directed mutagenesis was used to create deletion mutants of POTRA domains in Neisseria meningitidis Omp85.
- The functional impact of these POTRA domain deletions on Omp85 was assessed.
Main Results:
- Deletion of four out of five POTRA domains resulted in only minor defects in Omp85 function.
- The most carboxy-terminal POTRA domain (POTRA5) and the integral membrane domain were found to be essential for Omp85 activity.
Conclusions:
- The functional core of bacterial Omp85 comprises its membrane domain and a single POTRA domain (POTRA5).
- This finding is analogous to the Omp85 homologue in mitochondria, suggesting conserved functional principles in protein assembly machinery.
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