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Recent studies have demonstrated BamA, the central component of the β-barrel assembly machinery (BAM), as an important therapeutic target to combat infections caused by Acinetobacter baumannii and other Gram-negative pathogens. Homology modeling indicates BamA in A. baumannii consists of five polypeptide transport-associated (POTRA) domains and a β-barrel membrane domain. We characterized the POTRA domains of BamA from A. baumannii in solution using size-exclusion chromatography small angle X-ray scattering (SEC-SAXS) analysis and determined crystal structures in two conformational states that are drastically different than those previously observed in BamA from other bacteria, indicating that the POTRA domains are even more conformationally dynamic than has been observed previously. Molecular dynamics simulations of the POTRA domains from A. baumannii and Escherichia coli allowed us to identify key structural features that contribute to the observed novel states. Together, these studies expand on our current understanding of the conformational plasticity within BamA across differing bacterial species.
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http://dx.doi.org/10.1016/j.str.2024.08.013 | DOI Listing |
Structure
August 2025
Markey Center for Structural Biology, Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA. Electronic address:
N. gonorrhoeae (Ngo) causes the sexually transmitted infection gonorrhea with ∼106 million infections worldwide annually. Ngo infections can result in an increased risk of acquiring HIV, infertility, and blindness.
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August 2025
Department of Biological Sciences, Purdue University, West Lafayette, IN, USA; Markey Center for Structural Biology, Purdue University, West Lafayette, IN, USA; Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, USA. Electronic address: nnoina
F. nucleatum is a Gram-negative bacteria that causes oral infections and is linked to colorectal cancer. Pathogenicity relies on a type of β-barrel outer membrane protein (OMP) called an autotransporter.
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August 2025
Molecular Plant Biology, Department of Biology, University of Oxford, Oxford, UK.
The outer membranes of Gram-negative bacteria and endosymbiotic organelles mitochondria and chloroplasts contain β-barrel proteins essential for transporting metabolites, ions and proteins, as well as regulatory functions. While the assembly mechanisms of these proteins are well-studied in bacteria and mitochondria, they remain poorly understood in chloroplasts due to challenges in producing sufficient quantities of relevant plant proteins for structural and biochemical analyses. Here, we show that Oep80, the presumed core component of the chloroplastic β-barrel assembly machinery, can be overexpressed in bacteria and refolded in large quantities.
View Article and Find Full Text PDFUnlabelled: The β-barrel assembly machine (BAM) is an essential protein complex that folds and inserts outer membrane β-barrel proteins (OMPs) into the bacterial outer membrane. The BAM complex contains the essential BamA OMP with five soluble polypeptide transport-associated (POTRA) domains, which scaffold the essential BamD lipoprotein and the non-essential lipoproteins BamB/C/E. The importance of each BAM component has been investigated primarily using cell-based phenotypic assays, and structural data have revealed insights into the role of the BamA β-barrel in OMP folding.
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November 2024
Department of Biological Sciences, Purdue University, West Lafayette, IN, USA; Markey Center for Structural Biology, Purdue University, West Lafayette, IN, USA; Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, USA. Electronic address: nnoina
Recent studies have demonstrated BamA, the central component of the β-barrel assembly machinery (BAM), as an important therapeutic target to combat infections caused by Acinetobacter baumannii and other Gram-negative pathogens. Homology modeling indicates BamA in A. baumannii consists of five polypeptide transport-associated (POTRA) domains and a β-barrel membrane domain.
View Article and Find Full Text PDF