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Lateral opening and exit pore formation are required for BamA function.

ABSTRACT: The outer membrane of Gram-negative bacteria is replete with a host of ?-barrel outer membrane proteins (OMPs). Despite serving a variety of essential functions, including immune response evasion, the exact mechanism of OMP folding and membrane insertion remains largely unclear. The ?-barrel assembly machinery complex is required for OMP biogenesis. Crystal structures and molecular dynamics (MD) simulations of the central and essential component, BamA, suggest a mechanism involving lateral opening of its barrel domain. MD simulations reported here reveal an additional feature of BamA: a substrate exit pore positioned above the lateral opening site. Disulfide crosslinks that prevent lateral opening and exit pore formation result in a loss of BamA function, which can be fully rescued by the reductant tris(2-carboxyethyl)phosphine. These data provide strong evidence that lateral opening and exit pore formation are required for BamA function.

SUBMITTER: Noinaj N

PROVIDER: S-EPMC4100585 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature

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Lateral opening and exit pore formation are required for BamA function.

Noinaj Nicholas N Kuszak Adam J AJ Balusek Curtis C Gumbart James C JC Buchanan Susan K SK

Structure (London, England : 1993) 20140626 7

The outer membrane of Gram-negative bacteria is replete with a host of β-barrel outer membrane proteins (OMPs). Despite serving a variety of essential functions, including immune response evasion, the exact mechanism of OMP folding and membrane insertion remains largely unclear. The β-barrel assembly machinery complex is required for OMP biogenesis. Crystal structures and molecular dynamics (MD) simulations of the central and essential component, BamA, suggest a mechanism involving lateral openi ...[more]

PMID: 24980798

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