6ZY9

Cryo-EM structure of MlaFEDB in complex with AMP-PNP

Summary for 6ZY9

• Entry DOI: 10.2210/pdb6zy9/pdb
• Related: 6zy2 6zy3 6zy4
• EMDB information: 11555
• Descriptor: YrbD protein, ABC transporter maintaining OM lipid asymmetry, cytoplasmic STAS component, Toluene tolerance protein Ttg2A, ... (6 entities in total)
• Functional Keywords: phospholipid, phospholipid transport, abc transporter, mlafedb, mlafe, mlad, mlae, mlaf, mlab, outer membrane, mla transport pathway, lipid transport
• Biological source: Escherichia coli B185; More
• Total number of polymer chains: 12
• Total formula weight: 256238.70

Authors

Dong, C.J.,Dong, H.H. (deposition date: 2020-07-30, release date: 2020-11-25, Last modification date: 2024-05-01)

Primary citation

Tang, X.,Chang, S.,Qiao, W.,Luo, Q.,Chen, Y.,Jia, Z.,Coleman, J.,Zhang, K.,Wang, T.,Zhang, Z.,Zhang, C.,Zhu, X.,Wei, X.,Dong, C.,Zhang, X.,Dong, H.
Structural insights into outer membrane asymmetry maintenance in Gram-negative bacteria by MlaFEDB.
Nat.Struct.Mol.Biol., 28:81-91, 2021

PubMed Abstract: The highly asymmetric outer membrane of Gram-negative bacteria functions in the defense against cytotoxic substances, such as antibiotics. The Mla pathway maintains outer membrane lipid asymmetry by transporting phospholipids between the inner and outer membranes. It comprises six Mla proteins, MlaFEDBCA, including the ABC transporter MlaFEDB, which functions via an unknown mechanism. Here we determine cryo-EM structures of Escherichia coli MlaFEDB in an apo state and bound to phospholipid, ADP or AMP-PNP to a resolution of 3.3-4.1 Å and establish a proteoliposome-based transport system that includes MlaFEDB, MlaC and MlaA-OmpF to monitor the transport direction of phospholipids. In vitro transport assays and in vivo membrane permeability assays combined with mutagenesis identify functional residues that not only recognize and transport phospholipids but also regulate the activity and structural stability of the MlaFEDB complex. Our results provide mechanistic insights into the Mla pathway, which could aid antimicrobial drug development.

PubMed: 33199922
DOI: 10.1038/s41594-020-00532-y

Experimental method

ELECTRON MICROSCOPY (3.3 Å)