6FSU

Crystal structure of E.coli BamA beta-barrel with a C-terminal extension

Summary for 6FSU

• Entry DOI: 10.2210/pdb6fsu/pdb
• Descriptor: Outer membrane protein assembly factor BamA (2 entities in total)
• Functional Keywords: membrane protein
• Biological source: Escherichia coli O157:H7
• Total number of polymer chains: 2
• Total formula weight: 94059.80

Authors

Zahn, M.,Hartmann, J.-B.,Hiller, S. (deposition date: 2018-02-20, release date: 2018-11-14, Last modification date: 2024-01-17)

Primary citation

Hartmann, J.B.,Zahn, M.,Burmann, I.M.,Bibow, S.,Hiller, S.
Sequence-Specific Solution NMR Assignments of the beta-Barrel Insertase BamA to Monitor Its Conformational Ensemble at the Atomic Level.
J. Am. Chem. Soc., 140:11252-11260, 2018

PubMed Abstract: β-barrel outer membrane proteins (Omps) are key functional components of the outer membranes of Gram-negative bacteria, mitochondria, and plastids. In bacteria, their biogenesis requires the β-barrel-assembly machinery (Bam) with the central insertase BamA, but the exact translocation and insertion mechanism remains elusive. The BamA insertase features a loosely closed gating region between the first and last β-strand 16. Here, we describe ∼70% complete sequence-specific NMR resonance assignments of the transmembrane region of the BamA β-barrel in detergent micelles. On the basis of the assignments, NMR spectra show that the BamA barrel populates a conformational ensemble in slow exchange equilibrium, both in detergent micelles and lipid bilayer nanodiscs. Individual conformers can be selected from the ensemble by the introduction of a C-terminal strand extension, single-point mutations, or specific disulfide cross-linkings, and these modifications at the barrel seam are found to be allosterically coupled to sites at the entire barrel circumference. The resonance assignment provides a platform for mechanistic studies of BamA at atomic resolution, as well as for investigating interactions with potential antibiotic drugs and partner proteins.

PubMed: 30125090
DOI: 10.1021/jacs.8b03220

Experimental method

X-RAY DIFFRACTION (2.6 Å)