Cross‐species chimeras reveal BamA POTRA and β‐barrel domains must be fine‐tuned for efficient OMP insertion. Issue 4 (6th June 2015)

• Record Type: Journal Article
• Authors: Browning, Douglas F.; Bavro, Vassiliy N.; Mason, Jessica L.; Sevastsyanovich, Yanina R.; Rossiter, Amanda E.; Jeeves, Mark; Wells, Timothy J.; Knowles, Timothy J.; Cunningham, Adam F.; Donald, James W.; Palmer, Tracy; Overduin, Michael; Henderson, Ian R.
• Is Part Of: Molecular microbiology. Volume 97:Issue 4(2015)
• Page Start: 646
• Page End: 659
• Publication Date: 2015-06-06
• Subjects: Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.13052
• Languages: English
• ISSNs: 0950-382X

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>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 <italic>via</italic> 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 <italic>E</italic><italic>scherichia coli</italic> BamA fusion proteins, carrying either the β‐barrel or POTRA domains from various BamA orthologues, can functionally replace <italic>E</italic><italic>. coli</italic> BamA. 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.</p> </abstract>