6O30

Lipid A transporter MsbA from Salmonella typhimurium

Summary for 6O30

• Entry DOI: 10.2210/pdb6o30/pdb
• Descriptor: Lipid A export ATP-binding/permease protein MsbA (1 entity in total)
• Functional Keywords: msba, lipid a co-crystallization, abc transporters, staphylococcus typhimurium, membrane protein
• Biological source: Salmonella typhimurium
• Total number of polymer chains: 2
• Total formula weight: 127331.34

Authors

Padayatti, P.S.,Zhang, Q.,Wilson, I.A.,Lee, S.C.,Stanfield, R.L. (deposition date: 2019-02-25, release date: 2019-06-12, Last modification date: 2023-10-11)

Primary citation

Padayatti, P.S.,Lee, S.C.,Stanfield, R.L.,Wen, P.C.,Tajkhorshid, E.,Wilson, I.A.,Zhang, Q.
Structural Insights into the Lipid A Transport Pathway in MsbA.
Structure, 27:1114-1123.e3, 2019

PubMed Abstract: MsbA is an essential ATP-binding cassette transporter in Gram-negative bacteria that transports lipid A and lipopolysaccharide from the cytoplasmic leaflet to the periplasmic leaflet of the inner membrane. Here we report the X-ray structure of MsbA from Salmonella typhimurium at 2.8-Å resolution in an inward-facing conformation after cocrystallization with lipid A and using a stabilizing facial amphiphile. The structure displays a large amplitude opening in the transmembrane portal, which is likely required for lipid A to pass from its site of synthesis into the protein-enclosed transport pathway. Putative lipid A density is observed further inside the transmembrane cavity, consistent with a trap and flip model. Additional electron density attributed to lipid A is observed near an outer surface cleft at the periplasmic ends of the transmembrane helices. These findings provide new structural insights into the lipid A transport pathway through comparative analysis with existing MsbA structures.

PubMed: 31130486
DOI: 10.1016/j.str.2019.04.007

Experimental method

X-RAY DIFFRACTION (4.47 Å)