29EB

Cryo-EM structure of Acinetobacter baylyi LolA bound LolDF with lipoprotein

Summary for 29EB

• Entry DOI: 10.2210/pdb29eb/pdb
• EMDB information: 57113
• Descriptor: outer membrane lipoprotein EcnB, Lipoprotein-releasing system ATP-binding protein LolD, Putative integral membrane protein, ... (6 entities in total)
• Functional Keywords: loldf, /lipoprotein, /extraction, /transportation, transport protein
• Biological source: Acinetobacter baylyi ADP1; More
• Total number of polymer chains: 6
• Total formula weight: 162424.21

Authors

Dong, H.,Tang, X.,Qiao, W.,Pang, J. (deposition date: 2026-03-08, release date: 2026-11-04)

Primary citation

Pang, J.,Chen, Y.,Qiao, W.,Ju, Z.,Zhu, X.,Chang, S.,Wang, L.,Zhang, Z.,Zerang, Z.,Xu, S.,Chen, Y.,Li, C.,Ying, B.,Ding, B.S.,Chen, H.,Zhang, S.,Wei, X.,Tang, X.,Dong, H.
Mechanistic basis of LolDF-mediated lipoprotein transport in Acinetobacter.
Nat Commun, 17:-, 2026

PubMed Abstract: Lipoprotein trafficking is essential for Gram-negative bacteria to maintain the outer membrane, a permeability barrier critical for survival and antibiotic resistance. While most bacteria employ the canonical LolCDE transporter, Acinetobacter utilizes a noncanonical LolDF system whose mechanism has remained unclear. Here we determine cryo-EM structures of Acinetobacter baylyi LolDF in substrate-bound, AMP-PNP-bound, and LolA-bound states. LolDF forms a symmetric homodimer with a central cavity that accommodates three acyl chains at the membrane level, suggesting lateral extraction of lipoproteins directly from the inner membrane. AMP-PNP-driven conformational changes induce a coordinated symmetric constriction of the cavity that promotes substrate expulsion, distinct from the asymmetric mechanism observed in LolCDE. Functional studies further identify key door-bar residues required for transport and reveal that charged residues at the +3 position function as an inner membrane retention signal. Together, these findings reveal a mechanistically distinct lipoprotein trafficking system and provide a framework for targeting multidrug-resistant Gram-negative pathogens.

PubMed: 42736309
DOI: 10.1038/s41467-026-76802-y

Experimental method

ELECTRON MICROSCOPY (3.44 Å)