4PK1

Structure of BamB fused to a BamA POTRA domain fragment

4PK1 の概要

• エントリーDOI: 10.2210/pdb4pk1/pdb
• 分子名称: Chimera protein of Outer membrane protein assembly factors BamA and BamB (1 entity in total)
• 機能のキーワード: bam complex, fusion, protein binding
• 由来する生物種: Escherichia coli; 詳細
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 70037.84

構造登録者

Jansen, K.B.,Sousa, M.C. (登録日: 2014-05-13, 公開日: 2014-12-10, 最終更新日: 2023-12-27)

主引用文献

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

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: 25468906
DOI: 10.1074/jbc.M114.584524

実験手法

X-RAY DIFFRACTION (3.1 Å)