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Structure of BAM in MSP1E3D1 nanodiscs prepared from E. coli outer membranes
Structural highlights
FunctionBAMC_ECOLI Part of the outer membrane protein assembly complex, which is involved in assembly and insertion of beta-barrel proteins into the outer membrane. Nonessential member of the complex that stabilizes the interaction between the essential proteins BamA and BamD.[HAMAP-Rule:MF_00924][1] [2] [3] Publication Abstract from PubMedIn Gram-negative bacteria, the biogenesis of beta-barrel outer membrane proteins is mediated by the beta-barrel assembly machinery (BAM). The mechanism employed by BAM is complex and so far- incompletely understood. Here, we report the structures of BAM in nanodiscs, prepared using polar lipids and native membranes, where we observe an outward-open state. Mutations in the barrel domain of BamA reveal that plasticity in BAM is essential, particularly along the lateral seam of the barrel domain, which is further supported by molecular dynamics simulations that show conformational dynamics in BAM are modulated by the accessory proteins. We also report the structure of BAM in complex with EspP, which reveals an early folding intermediate where EspP threads from the underside of BAM and incorporates into the barrel domain of BamA, supporting a hybrid-barrel budding mechanism in which the substrate is folded into the membrane sequentially rather than as a single unit. Plasticity within the barrel domain of BamA mediates a hybrid-barrel mechanism by BAM.,Wu R, Bakelar JW, Lundquist K, Zhang Z, Kuo KM, Ryoo D, Pang YT, Sun C, White T, Klose T, Jiang W, Gumbart JC, Noinaj N Nat Commun. 2021 Dec 8;12(1):7131. doi: 10.1038/s41467-021-27449-4. PMID:34880256[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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