Insights into bacterial lipoprotein trafficking from a structure of LolA bound to the LolC periplasmic domain.
Proc Natl Acad Sci U S A
Proceedings of the National Academy of Sciences
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Kaplan, E., Greene, N., Crow, A., & Koronakis, V. (2018). Insights into bacterial lipoprotein trafficking from a structure of LolA bound to the LolC periplasmic domain.. Proc Natl Acad Sci U S A, 115 (31), E7389-E7397. https://doi.org/10.1073/pnas.1806822115
In Gram-negative bacteria, outer-membrane lipoproteins are essential for maintaining cellular integrity, transporting nutrients, establishing infections, and promoting the formation of biofilms. The LolCDE ABC transporter, LolA chaperone, and LolB outer-membrane receptor form an essential system for transporting newly matured lipoproteins from the outer leaflet of the cytoplasmic membrane to the innermost leaflet of the outer membrane. Here, we present a crystal structure of LolA in complex with the periplasmic domain of LolC. The structure reveals how a solvent-exposed β-hairpin loop (termed the "Hook") and trio of surface residues (the "Pad") of LolC are essential for recruiting LolA from the periplasm and priming it to receive lipoproteins. Experiments with purified LolCDE complex demonstrate that association with LolA is independent of nucleotide binding and hydrolysis, and homology models based on the MacB ABC transporter predict that LolA recruitment takes place at a periplasmic site located at least 50 Å from the inner membrane. Implications for the mechanism of lipoprotein extraction and transfer are discussed. The LolA-LolC structure provides atomic details on a key protein interaction within the Lol pathway and constitutes a vital step toward the complete molecular understanding of this important system.
Periplasm, Escherichia coli Proteins, Periplasmic Binding Proteins, ATP-Binding Cassette Transporters, Adenosine Triphosphate, Protein Interaction Mapping, Protein Transport, Hydrolysis, Models, Molecular
This work was supported by grants from the UK Medical Research Council (MR/N000994/1) and the Wellcome Trust (101828/Z/13/Z).
Medical Research Council (MR/N000994/1)
Wellcome Trust (101828/Z/13/Z)
External DOI: https://doi.org/10.1073/pnas.1806822115
This record's URL: https://www.repository.cam.ac.uk/handle/1810/284440