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Cross-species chimeras reveal BamA POTRA and β-barrel domains must be fine-tuned for efficient OMP insertion

Browning, DF and Bavro, VN and Mason, JL and Sevastsyanovich, YR and Rossiter, AE and Jeeves, M and Wells, TJ and Knowles, TJ and Cunningham, AF and Donald, JW and Palmer, T and Overduin, M and Henderson, IR (2015) 'Cross-species chimeras reveal BamA POTRA and β-barrel domains must be fine-tuned for efficient OMP insertion.' Molecular Microbiology, 97 (4). 646 - 659. ISSN 1365-2958

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Abstract

BAM is a conserved molecular machine, the central component of which is BamA. Orthologues of BamA are found in all Gram-negative bacteria, chloroplasts and mitochondria where it is required for the folding and insertion of β-barrel containing integral outer membrane proteins (OMPs) into the outer membrane. BamA binds unfolded β-barrel precursors via the five polypeptide transport-associated (POTRA) domains at its N-terminus. The C-terminus of BamA folds into a β-barrel domain, which tethers BamA to the outer membrane and is involved in OMP insertion. BamA orthologues are found in all Gram-negative bacteria and appear to function in a species-specific manner. Here we investigate the nature of this species-specificity by examining whether chimeric Escherichia coliBamA fusion proteins, carrying either the β-barrel or POTRA domains from various BamA orthologues, can functionally replace E.coliBamA. We demonstrate that the β-barrel domains of many BamA orthologues are functionally interchangeable. We show that defects in the orthologous POTRA domains can be rescued by compensatory mutations within the β-barrel. These data reveal that the POTRA and barrel domains must be precisely aligned to ensure efficient OMP insertion.

Item Type: Article
Subjects: Q Science > QR Microbiology
Divisions: Faculty of Science and Health > Biological Sciences, School of
Depositing User: Jim Jamieson
Date Deposited: 15 Dec 2016 14:25
Last Modified: 24 Nov 2017 15:15
URI: http://repository.essex.ac.uk/id/eprint/17727

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