Cryo-EM structures of LolCDE reveal the molecular mechanism of bacterial lipoprotein sorting in Escherichia coli

Weiwei Bei; Qingshan Luo; Huigang Shi; Haizhen Zhou; Min Zhou; Xinzheng Zhang; Yihua Huang

doi:10.1371/journal.pbio.3001823

Cryo-EM structures of LolCDE reveal the molecular mechanism of bacterial lipoprotein sorting in Escherichia coli

PLoS Biol. 2022 Oct 13;20(10):e3001823. doi: 10.1371/journal.pbio.3001823. eCollection 2022 Oct.

Authors

Weiwei Bei^{1

2}, Qingshan Luo¹, Huigang Shi^{1

2}, Haizhen Zhou^{1

2}, Min Zhou³, Xinzheng Zhang^{1

2}, Yihua Huang^{1

2}

Affiliations

¹ National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
² University of Chinese Academy of Sciences, Beijing, China.
³ Institute of Bio-analytical Chemistry, School of Chemical Engineering, Nanjing University of Science and Technology, No.200 Xiao Ling Wei Street, Nanjing, China.

Abstract

Bacterial lipoproteins perform a diverse array of functions including bacterial envelope biogenesis and microbe-host interactions. Lipoproteins in gram-negative bacteria are sorted to the outer membrane (OM) via the localization of lipoproteins (Lol) export pathway. The ATP-binding cassette (ABC) transporter LolCDE initiates the Lol pathway by selectively extracting and transporting lipoproteins for trafficking. Here, we report cryo-EM structures of LolCDE in apo, lipoprotein-bound, and AMPPNP-bound states at a resolution of 3.5 to 4.2 Å. Structure-based disulfide crosslinking, photo-crosslinking, and functional complementation assay verify the apo-state structure and reveal the molecular details regarding substrate selectivity and substrate entry route. Our studies snapshot 3 functional states of LolCDE in a transport cycle, providing deep insights into the mechanisms that underlie LolCDE-mediated lipoprotein sorting in E. coli.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

ATP-Binding Cassette Transporters / metabolism
Adenylyl Imidodiphosphate / metabolism
Bacteria / metabolism
Bacterial Outer Membrane Proteins / metabolism
Cryoelectron Microscopy
Disulfides / metabolism
Escherichia coli Proteins* / metabolism
Escherichia coli* / genetics
Escherichia coli* / metabolism
Lipoproteins / metabolism

Substances

Escherichia coli Proteins
Adenylyl Imidodiphosphate
Lipoproteins
ATP-Binding Cassette Transporters
Disulfides
Bacterial Outer Membrane Proteins

Grants and funding

This work was supported by grants from the National Natural Science Foundation of China (31625009 to Y.H. and 21575065 to X.Z.), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB37020201 to Y.H.), the Ministry of Science and Technology (2016YFA0500404 to Y.H.) and the China Postdoctoral Science Foundation (BX20190356 to Q.L.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.