4PK1
Structure of BamB fused to a BamA POTRA domain fragment
Summary for 4PK1
| Entry DOI | 10.2210/pdb4pk1/pdb |
| Descriptor | Chimera protein of Outer membrane protein assembly factors BamA and BamB (1 entity in total) |
| Functional Keywords | bam complex, fusion, protein binding |
| Biological source | Escherichia coli More |
| Total number of polymer chains | 1 |
| Total formula weight | 70037.84 |
| Authors | Jansen, K.B.,Sousa, M.C. (deposition date: 2014-05-13, release date: 2014-12-10, Last modification date: 2023-12-27) |
| Primary citation | Jansen, K.B.,Baker, S.L.,Sousa, M.C. Crystal Structure of BamB Bound to a Periplasmic Domain Fragment of BamA, the Central Component of the beta-Barrel Assembly Machine. J.Biol.Chem., 290:2126-2136, 2015 Cited by PubMed Abstract: The β-barrel assembly machinery (BAM) mediates folding and insertion of β-barrel outer membrane proteins (OMPs) into the outer membrane of Gram-negative bacteria. BAM is a five-protein complex consisting of the β-barrel OMP BamA and lipoproteins BamB, -C, -D, and -E. High resolution structures of all the individual BAM subunits and a BamD-BamC complex have been determined. However, the overall complex architecture remains elusive. BamA is the central component of BAM and consists of a membrane-embedded β-barrel and a periplasmic domain with five polypeptide translocation-associated (POTRA) motifs thought to interact with the accessory lipoproteins. Here we report the crystal structure of a fusion between BamB and a POTRA3-5 fragment of BamA. Extended loops 13 and 17 protruding from one end of the BamB β-propeller contact the face of the POTRA3 β-sheet in BamA. The interface is stabilized by several hydrophobic contacts, a network of hydrogen bonds, and a cation-π interaction between BamA Tyr-255 and BamB Arg-195. Disruption of BamA-BamB binding by BamA Y255A and probing of the interface by disulfide bond cross-linking validate the physiological relevance of the observed interface. Furthermore, the structure is consistent with previously published mutagenesis studies. The periplasmic five-POTRA domain of BamA is flexible in solution due to hinge motions in the POTRA2-3 linker. Modeling BamB in complex with full-length BamA shows BamB binding at the POTRA2-3 hinge, suggesting a role in modulation of BamA flexibility and the conformational changes associated with OMP folding and insertion. PubMed: 25468906DOI: 10.1074/jbc.M114.584524 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (3.1 Å) |
Structure validation
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