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Article
Flexibility in the Periplasmic Domain of BamA is Important for Function
Structure (2017)
  • Lisa R. Warner, University of Colorado
  • Petia Z. Gatzeva-Topalova, University of Colorado
  • Pamela A. Doerner, University of Colorado
  • Arthur Pardi, University of Colorado
  • Marcelo C. Sousa, University of Colorado
Abstract
The β-barrel assembly machine (BAM) mediates the biogenesis of outer membrane proteins (OMPs) in Gram-negative bacteria. BamA, the central BAM subunit composed of a transmembrane β-barrel domain linked to five polypeptide transport-associated (POTRA) periplasmic domains, is thought to bind nascent OMPs and undergo conformational cycling to catalyze OMP folding and insertion. One model is that conformational flexibility between POTRA domains is part of this conformational cycling. Nuclear magnetic resonance (NMR) spectroscopy was used here to study the flexibility of the POTRA domains 1–5 in solution. NMR relaxation studies defined effective rotational correlational times and together with residual dipolar coupling data showed that POTRA1–2 is flexibly linked to POTRA3–5. Mutants of BamA that restrict flexibility between POTRA2 and POTRA3 by disulfide crosslinking displayed impaired function in vivo. Together these data strongly support a model in which conformational cycling of hinge motions between POTRA2 and POTRA3 in BamA is required for biological function.
Keywords
  • Escherichia coli,
  • BamA,
  • residual dipolar couplings,
  • interdomain flexibility,
  • POTRA,
  • disulfide crosslinking
Disciplines
Publication Date
January 3, 2017
DOI
10.1016/j.str.2016.11.013
Citation Information
Lisa R. Warner, Petia Z. Gatzeva-Topalova, Pamela A. Doerner, Arthur Pardi, et al.. "Flexibility in the Periplasmic Domain of BamA is Important for Function" Structure Vol. 25 Iss. 1 (2017) p. 94 - 106
Available at: http://works.bepress.com/lisa-warner/24/