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Updated: Jul 10, 2026

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.
Abstract:
beta-Barrel proteins are present in the outer membranes of Gram-negative bacteria, mitochondria and chloroplasts. The central component of their assembly machinery is called Omp85 in bacteria. Omp85 is predicted to consist of an integral membrane domain and an amino-terminal periplasmic extension containing five polypeptide-transport-associated (POTRA) domains. We have addressed the function of these domains by creating POTRA domain deletions in Omp85 of Neisseria meningitidis. Four POTRA domains could be deleted with only slight defects in Omp85 function. Only the most carboxy-terminal POTRA domain was essential, as was the membrane domain. Thus, similar to the mitochondrial Omp85 homologue, the functional core of bacterial Omp85 consists of its membrane domain and a single POTRA domain, that is, POTRA5.
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