5OR1

BamA structure of Salmonella enterica

Summary for 5OR1

• Entry DOI: 10.2210/pdb5or1/pdb
• Descriptor: Outer membrane protein assembly factor BamA (1 entity in total)
• Functional Keywords: outer membrane protein, membrane protein
• Biological source: Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720)
• Total number of polymer chains: 1
• Total formula weight: 89617.26

Authors

Dong, C.,Gu, Y. (deposition date: 2017-08-14, release date: 2018-02-14, Last modification date: 2024-05-08)

Primary citation

Gu, Y.,Zeng, Y.,Wang, Z.,Dong, C.
BamA beta 16C strand and periplasmic turns are critical for outer membrane protein insertion and assembly.
Biochem. J., 474:3951-3961, 2017

PubMed Abstract: Outer membrane (OM) β-barrel proteins play important roles in importing nutrients, exporting wastes and conducting signals in Gram-negative bacteria, mitochondria and chloroplasts. The outer membrane proteins (OMPs) are inserted and assembled into the OM by OMP85 family proteins. In , the β-barrel assembly machinery (BAM) contains four lipoproteins such as BamB, BamC, BamD and BamE, and one OMP BamA, forming a 'top hat'-like structure. Structural and functional studies of the BAM machinery have revealed that the rotation of periplasmic ring may trigger the barrel β1C-β6C scissor-like movement that promote the unfolded OMP insertion without using ATP. Here, we report the BamA C-terminal barrel structure of Typhimurium str. LT2 and functional assays, which reveal that the BamA's C-terminal residue Trp, the β16C strand of the barrel and the periplasmic turns are critical for the functionality of BamA. These findings indicate that the unique β16C strand and the periplasmic turns of BamA are important for the outer membrane insertion and assembly. The periplasmic turns might mediate the rotation of the periplasmic ring to the scissor-like movement of BamA β1C-β6C, triggering the OMP insertion. These results are important for understanding the OMP insertion in Gram-negative bacteria, as well as in mitochondria and chloroplasts.

PubMed: 28974626
DOI: 10.1042/BCJ20170636

Experimental method

X-RAY DIFFRACTION (2.92 Å)