5X5Y

A membrane protein complex

Summary for 5X5Y

• Entry DOI: 10.2210/pdb5x5y/pdb
• Descriptor: Probable ATP-binding component of ABC transporter, Uncharacterized protein (3 entities in total)
• Functional Keywords: membrane protein, transporter
• Biological source: Pseudomonas aeruginosa PAO1; More
• Total number of polymer chains: 4
• Total formula weight: 134212.67

Authors

Luo, Q.,Yang, X.,Huang, Y. (deposition date: 2017-02-18, release date: 2017-04-05, Last modification date: 2023-11-22)

Primary citation

Luo, Q.,Yang, X.,Yu, S.,Shi, H.,Wang, K.,Xiao, L.,Zhu, G.,Sun, C.,Li, T.,Li, D.,Zhang, X.,Zhou, M.,Huang, Y.
Structural basis for lipopolysaccharide extraction by ABC transporter LptB2FG
Nat. Struct. Mol. Biol., 24:469-474, 2017

PubMed Abstract: After biosynthesis, bacterial lipopolysaccharides (LPS) are transiently anchored to the outer leaflet of the inner membrane (IM). The ATP-binding cassette (ABC) transporter LptBFG extracts LPS molecules from the IM and transports them to the outer membrane. Here we report the crystal structure of nucleotide-free LptBFG from Pseudomonas aeruginosa. The structure reveals that lipopolysaccharide transport proteins LptF and LptG each contain a transmembrane domain (TMD), a periplasmic β-jellyroll-like domain and a coupling helix that interacts with LptB on the cytoplasmic side. The LptF and LptG TMDs form a large outward-facing V-shaped cavity in the IM. Mutational analyses suggest that LPS may enter the central cavity laterally, via the interface of the TMD domains of LptF and LptG, and is expelled into the β-jellyroll-like domains upon ATP binding and hydrolysis by LptB. These studies suggest a mechanism for LPS extraction by LptBFG that is distinct from those of classical ABC transporters that transport substrates across the IM.

PubMed: 28394325
DOI: 10.1038/nsmb.3399

Experimental method

X-RAY DIFFRACTION (3.465 Å)