13HQ

Cryo-EM structure of Pseudomonas aeruginosa soluble lipoprotein PA3214

This is a non-PDB format compatible entry.

Summary for 13HQ

• Entry DOI: 10.2210/pdb13hq/pdb
• EMDB information: 77071
• Descriptor: ABC-type transport auxiliary lipoprotein component domain-containing protein (1 entity in total)
• Functional Keywords: lipoprotein, pseudomonas aeruginosa, mce system, lipid transport
• Biological source: Pseudomonas aeruginosa PAO1
• Total number of polymer chains: 8
• Total formula weight: 183381.54

Authors

Redler, R.,Giacometti, S.I.,Coudray, N.,Bhabha, G.,Ekiert, D.C. (deposition date: 2026-05-06, release date: 2026-05-20, Last modification date: 2026-06-03)

Primary citation

Giacometti, S.I.,Coudray, N.,Redler, R.L.,Bhabha, G.,Ekiert, D.C.
Interactions of outer membrane lipoproteins P. aeruginosa PA3214 and E. coli PqiC with their MCE protein binding partners, PA3213 and PqiB.
Biorxiv, 2026

PubMed Abstract: Members of the Mammalian Cell Entry (MCE) superfamily interact with other proteins to form diverse architectures for the transport of hydrophobic molecules across the cell envelope in Gram-negative bacteria. Some of these trans-envelope MCE protein complexes include a PqiC-like outer membrane (OM) lipoprotein component. The best-studied member of this group of OM lipoproteins is PqiC, from the PqiABC system, which can form an octameric ring. How PqiC-like lipoproteins interact with their MCE protein binding partners to facilitate transport is not well understood. Here we report the cryo-electron microscopy structures of PA3214, a homolog of PqiC, in the context of the full MCE transport PA3211-PA3214 system. Our structure provides insight into the biological assembly of the lipoprotein and interactions with its binding partner, MCE protein PA3213. We utilize deep mutational scanning to identify functionally important sites in PqiC in an unbiased manner. Through phenotypic and biochemical experiments, we characterize the interactions of the lipoproteins PqiC and PA3214 with their associated MCE proteins PqiB and PA3213, thus providing a model for how some MCE proteins employ a C-terminal peptide to mediate key interactions with their cognate lipoproteins at the OM.

PubMed: 42146607
DOI: 10.64898/2026.05.09.724024

Experimental method

ELECTRON MICROSCOPY (2.67 Å)