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

TY - JOUR

T1 - Cross-species chimeras reveal BamA POTRA and β-barrel domains must be fine-tuned for efficient OMP insertion

AU - Browning, Douglas F.

AU - Bavro, Vassiliy N.

AU - Mason, Jessica L.

AU - Sevastsyanovich, Yanina R.

AU - Rossiter, Amanda E.

AU - Jeeves, Mark

AU - Wells, Timothy J.

AU - Knowles, Timothy J.

AU - Cunningham, Adam F.

AU - Donald, James W.

AU - Palmer, Tracy

AU - Overduin, Michael

AU - Henderson, Ian R.

PY - 2015/8/1

Y1 - 2015/8/1

N2 - 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.

AB - 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.

UR - http://www.scopus.com/record/display.uri?eid=2-s2.0-84939263331&origin=resultslist&sort=plf-f&src=s&st1=Cross-species+chimeras+reveal+BamA+POTRA+and+%ce%b2-barrel+domains+must+be+fine-tuned+for+efficient+OMP+insertion&st2=&sid=8BACC8C955F9CFED18146E7591CC5355.iqs8TDG0Wy6BURhzD3nFA%3a10&sot=b&sdt=b&sl=123&s=TITLE-ABS-KEY%28Cross-species+chimeras+reveal+BamA+POTRA+and+%ce%b2-barrel+domains+must+be+fine-tuned+for+efficient+OMP+insertion%29&relpos=0&citeCnt=0&searchTerm=TITLE-ABS-KEY%28Cross-species+chimeras+reveal+BamA+POTRA+and+%CE%B2-barrel+domains+must+be+fine-tuned+for+efficient+OMP+insertion%29

U2 - 10.1111/mmi.13052

DO - 10.1111/mmi.13052

M3 - Article

AN - SCOPUS:84930536172

SN - 0950-382X

VL - 97

SP - 646

EP - 659

JO - Molecular Microbiology

JF - Molecular Microbiology

IS - 4

ER -