Structural basis for substrate selection by the translocation and assembly module of the β-barrel assembly machinery

Rebecca S. Bamert, Karl Lundquist, Hyea Hwang, Chaille T. Webb, Takoya Shiota, Christopher J. Stubenrauch, Mathew J. Belousoff, Robert J.A. Goode, Ralf B. Schittenhelm, Richard Zimmerman, Martin Jung, James C Gumbart, Trevor Lithgow

Research output: Contribution to journalArticleResearchpeer-review

Abstract

The assembly of proteins into bacterial outer membranes is a key cellular process that we are only beginning to understand, mediated by the β-barrel assembly machinery (BAM). Two crucial elements of that machinery are the core BAM complex and the translocation and assembly module (TAM), with each containing a member of the Omp85 superfamily of proteins: BamA in the BAM complex, TamA in the TAM. Here, we used the substrate protein FimD as a model to assess the selectivity of substrate interactions for the TAM relative to those of the BAM complex. A peptide scan revealed that TamA and BamA bind the β-strands of FimD, and do so selectively. Chemical cross-linking and molecular dynamics are consistent with this interaction taking place between the first and last strand of the TamA barrel domain, providing the first experimental evidence of a lateral gate in TamA: a structural element implicated in membrane protein assembly. We suggest that the lateral gates in TamA and BamA provide different environments for substrates to engage, with the differences observed here beginning to address how the TAM can be more effective than the BAM complex in the folding of some substrate proteins.

Original languageEnglish
Pages (from-to)142-156
Number of pages15
JournalMolecular Microbiology
Volume106
Issue number1
DOIs
Publication statusPublished - 1 Oct 2017

Cite this

Bamert, Rebecca S. ; Lundquist, Karl ; Hwang, Hyea ; Webb, Chaille T. ; Shiota, Takoya ; Stubenrauch, Christopher J. ; Belousoff, Mathew J. ; Goode, Robert J.A. ; Schittenhelm, Ralf B. ; Zimmerman, Richard ; Jung, Martin ; Gumbart, James C ; Lithgow, Trevor. / Structural basis for substrate selection by the translocation and assembly module of the β-barrel assembly machinery. In: Molecular Microbiology. 2017 ; Vol. 106, No. 1. pp. 142-156.
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abstract = "The assembly of proteins into bacterial outer membranes is a key cellular process that we are only beginning to understand, mediated by the β-barrel assembly machinery (BAM). Two crucial elements of that machinery are the core BAM complex and the translocation and assembly module (TAM), with each containing a member of the Omp85 superfamily of proteins: BamA in the BAM complex, TamA in the TAM. Here, we used the substrate protein FimD as a model to assess the selectivity of substrate interactions for the TAM relative to those of the BAM complex. A peptide scan revealed that TamA and BamA bind the β-strands of FimD, and do so selectively. Chemical cross-linking and molecular dynamics are consistent with this interaction taking place between the first and last strand of the TamA barrel domain, providing the first experimental evidence of a lateral gate in TamA: a structural element implicated in membrane protein assembly. We suggest that the lateral gates in TamA and BamA provide different environments for substrates to engage, with the differences observed here beginning to address how the TAM can be more effective than the BAM complex in the folding of some substrate proteins.",
author = "Bamert, {Rebecca S.} and Karl Lundquist and Hyea Hwang and Webb, {Chaille T.} and Takoya Shiota and Stubenrauch, {Christopher J.} and Belousoff, {Mathew J.} and Goode, {Robert J.A.} and Schittenhelm, {Ralf B.} and Richard Zimmerman and Martin Jung and Gumbart, {James C} and Trevor Lithgow",
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Structural basis for substrate selection by the translocation and assembly module of the β-barrel assembly machinery. / Bamert, Rebecca S.; Lundquist, Karl; Hwang, Hyea; Webb, Chaille T.; Shiota, Takoya; Stubenrauch, Christopher J.; Belousoff, Mathew J.; Goode, Robert J.A.; Schittenhelm, Ralf B.; Zimmerman, Richard; Jung, Martin; Gumbart, James C; Lithgow, Trevor.

In: Molecular Microbiology, Vol. 106, No. 1, 01.10.2017, p. 142-156.

Research output: Contribution to journalArticleResearchpeer-review

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