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-Structure paper
Title | Cryo-EM structures reveal multiple stages of bacterial outer membrane protein folding. |
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Journal, issue, pages | Cell, Vol. 185, Issue 7, Page 1143-1156.e13, Year 2022 |
Publish date | Mar 31, 2022 |
Authors | Matthew Thomas Doyle / John R Jimah / Tyrone Dowdy / Shannon I Ohlemacher / Mioara Larion / Jenny E Hinshaw / Harris D Bernstein / |
PubMed Abstract | Transmembrane β barrel proteins are folded into the outer membrane (OM) of Gram-negative bacteria by the β barrel assembly machinery (BAM) via a poorly understood process that occurs without known ...Transmembrane β barrel proteins are folded into the outer membrane (OM) of Gram-negative bacteria by the β barrel assembly machinery (BAM) via a poorly understood process that occurs without known external energy sources. Here, we used single-particle cryo-EM to visualize the folding dynamics of a model β barrel protein (EspP) by BAM. We found that BAM binds the highly conserved "β signal" motif of EspP to correctly orient β strands in the OM during folding. We also found that the folding of EspP proceeds via "hybrid-barrel" intermediates in which membrane integrated β sheets are attached to the essential BAM subunit, BamA. The structures show an unprecedented deflection of the membrane surrounding the EspP intermediates and suggest that β sheets progressively fold toward BamA to form a β barrel. Along with in vivo experiments that tracked β barrel folding while the OM tension was modified, our results support a model in which BAM harnesses OM elasticity to accelerate β barrel folding. |
External links | Cell / PubMed:35294859 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.6 - 4.8 Å |
Structure data | EMDB-26105, PDB-7tsz: EMDB-26106, PDB-7tt0: EMDB-26107, PDB-7tt1: EMDB-26108, PDB-7tt2: EMDB-26109, PDB-7tt3: EMDB-26110, PDB-7tt4: EMDB-26111, PDB-7tt5: EMDB-26112, PDB-7tt6: EMDB-26113, PDB-7tt7: EMDB-26114, PDB-7ttc: |
Chemicals | ChemComp-K33: |
Source |
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Keywords | MEMBRANE PROTEIN / membrane protein folding / membrane dynamics / outer membrane protein / BAM / beta-barrel |