Structural basis for bacterial lipoprotein relocation by the transporter LolCDE

Tang, Xiaodi; Chang, Shenghai; Zhang, Ke; Luo, Qinghua; Zhang, Zhengyu; Wang, Ting; Wen, Qian; Wang, Chen; Shen, Chongrong; Zhang, Zhibo; Zhu, Xiaofeng; Wei, Xiawei; Dong, Changjiang; Zhang, Xing; Dong, Haohao

doi:10.1038/s41594-021-00573-x

Cited by 38 publications

(59 citation statements)

References 64 publications

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“…Consistent with its lower activity, LolCDE in LMNG demonstrates only half conversion to NBD-closed conformation upon AMP-PNP inhibition, which is in contrast with full NBD-closure of vanadate-trapped LolCDE in nanodiscs (Supplementary Fig. 6c ), and a major portion of LolCDE in LMNG does not release the bound lipoprotein under continuous ATP hydrolysis condition (lipoprotein- and LolA-bound LolCDE structure) 22 . Taken together, most differences between our LolCDE structures and those from Tang et al likely stem from the distinct environments in which LolCDE resides.…”

Section: Discussionmentioning

confidence: 73%

“…Recently Tang et al published various cryo-EM structures of E. coli LolCDE in detergent (lauryl maltose neopentyl glycol, LMNG) using four different conditions: no added nucleotide, β-γ-imidoadenosine 5′-phosphate (AMP-PNP), continuous ATP turnover with LolA, and ADP 22 . Their lipoprotein-bound LolCDE structures (with or without LolA binding) from all four conditions display essentially identical conformation, and the four different structures (apo, lipoprotein-bound, lipoprotein- and LolA-bound, and NBD-closed) were proposed to represent four states in lipoprotein transport 22 . Our structure of nucleotide-free LolCDE in nanodiscs is similar to the lipoprotein-bound LolCDE structures from Tang et al, but with a critical difference in the conformation of R3 of the lipoprotein.…”

Section: Discussionmentioning

confidence: 99%

“…While the structures of LolCDE in detergent were reported recently 22 , structural studies have not been performed for lipoprotein transporter in a native-like lipid bilayer. In this work, we determined the cryo-EM structures of nucleotide-free and ADP-vanadate-bound E. coli LolCDE in nanodiscs, at 3.8-Å and 3.5-Å resolutions, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Mechanism of LolCDE as a molecular extruder of bacterial triacylated lipoproteins

et al. 2021

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Lipoproteins are important for bacterial growth and antibiotic resistance. These proteins use lipid acyl chains attached to the N-terminal cysteine residue to anchor on the outer surface of cytoplasmic membrane. In Gram-negative bacteria, many lipoproteins are transported to the outer membrane (OM), a process dependent on the ATP-binding cassette (ABC) transporter LolCDE which extracts the OM-targeted lipoproteins from the cytoplasmic membrane. Lipid-anchored proteins pose a unique challenge for transport machinery as they have both hydrophobic lipid moieties and soluble protein component, and the underlying mechanism is poorly understood. Here we determined the cryo-EM structures of nanodisc-embedded LolCDE in the nucleotide-free and nucleotide-bound states at 3.8-Å and 3.5-Å resolution, respectively. The structural analyses, together with biochemical and mutagenesis studies, uncover how LolCDE recognizes its substrate by interacting with the lipid and N-terminal peptide moieties of the lipoprotein, and identify the amide-linked acyl chain as the key element for LolCDE interaction. Upon nucleotide binding, the transmembrane helices and the periplasmic domains of LolCDE undergo large-scale, asymmetric movements, resulting in extrusion of the captured lipoprotein. Comparison of LolCDE and MacB reveals the conserved mechanism of type VII ABC transporters and emphasizes the unique properties of LolCDE as a molecule extruder of triacylated lipoproteins.

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Section: Discussionmentioning

confidence: 73%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mechanism of LolCDE as a molecular extruder of bacterial triacylated lipoproteins

et al. 2021

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“…LolC recruits LolA via its two structure-specific features, a β-hairpin “Hook” and a three-residue “Pad” ( 22 ), while LolE was identified by in vivo cross-linking as the lipoprotein binding site ( 21 ). Recent cryogenic electron microscopy (cryo-EM) structures of E. coli LolCDE revealed how lipoproteins are recognized ( 23 , 24 ). The central channel formed by LolC and LolE transmembrane helices accommodate the three acyl chains of the lipoprotein in two hydrophobic pockets elevated above the membrane plane while, in agreement with the cross-linking data, the peptide portion extends upwards, forming interactions with LolE but not LolC.…”

mentioning

confidence: 99%

Structural basis of lipoprotein recognition by the bacterial Lol trafficking chaperone LolA

Kaplan

Greene

Jepson

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

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In gram-negative bacteria, lipoproteins are vital structural components of the outer membrane (OM) and crucial elements of machineries central to the physiology of the cell envelope. A dedicated apparatus, the Lol system, is required for the correct localization of OM lipoproteins and is essential for viability. The periplasmic chaperone LolA is central to this trafficking pathway, accepting triacylated lipoproteins from the inner membrane transporter LolCDE, before carrying them across the periplasm to the OM receptor LolB. Here, we report a crystal structure of liganded LolA, generated in vivo, revealing the molecular details of lipoprotein association. The structure highlights how LolA, initially primed to receive lipoprotein by interaction with LolC, further opens to accommodate the three ligand acyl chains in a precise conformation within its cavity. LolA forms extensive interactions with the acyl chains but not with any residue of the cargo, explaining the chaperone’s ability to transport structurally diverse lipoproteins. Structural characterization of a ligandedLolA variant incapable of lipoprotein release reveals aberrant association, demonstrating the importance of the LolCDE-coordinated, sequential opening of LolA for inserting lipoprotein in a manner productive for subsequent trafficking. Comparison with existing structures of LolA in complex with LolC or LolCDE reveals substantial overlap of the lipoprotein and LolC binding sites within the LolA cavity, demonstrating that insertion of lipoprotein acyl chains physically disengages the chaperone protein from the transporter by perturbing interaction with LolC. Taken together, our data provide a key step toward a complete understanding of a fundamentally important trafficking pathway.

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“…Relatedly, the first structure of this reaction center resulted in the Nobel Prize in Chemistry awarded to Michel, Deisenhofer and Huber in 1988. Other full-length structures have appeared since, notably in multi-subunit complexes solved by single particle cryo-electron microscopy ( Sun et al, 2018 ; Sharma et al, 2021 ; Tang et al, 2021 ).…”

Section: Discussionmentioning

confidence: 99%

Bacterial Lipoprotein Posttranslational Modifications. New Insights and Opportunities for Antibiotic and Vaccine Development

2021

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Lipoproteins are some of the most abundant proteins in bacteria. With a lipid anchor to the cell membrane, they function as enzymes, inhibitors, transporters, structural proteins, and as virulence factors. Lipoproteins activate the innate immune system and have biotechnological applications. The first lipoprotein was described by Braun and Rehn in 1969. Up until recently, however, work on lipoproteins has been sluggish, in part due to the challenges of handling proteins that are anchored to membranes by covalently linked lipids or are membrane integral. Activity in the area has quickened of late. In the past 5 years, high-resolution structures of the membrane enzymes of the canonical lipoprotein synthesis pathway have been determined, new lipoprotein types have been discovered and the enzymes responsible for their synthesis have been characterized biochemically. This has led to a flurry of activity aimed at developing novel antibiotics targeting these enzymes. In addition, surface exposed bacterial lipoproteins have been utilized as candidate vaccine antigens, and their potential to act as self-adjuvanting antigens is increasingly recognized. A summary of the latest developments in lipoproteins and their synthesis, as well as how this information is being exploited for therapeutic purposes is presented here.

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Structural basis for bacterial lipoprotein relocation by the transporter LolCDE

Cited by 38 publications

References 64 publications

Mechanism of LolCDE as a molecular extruder of bacterial triacylated lipoproteins

Mechanism of LolCDE as a molecular extruder of bacterial triacylated lipoproteins

Structural basis of lipoprotein recognition by the bacterial Lol trafficking chaperone LolA

Bacterial Lipoprotein Posttranslational Modifications. New Insights and Opportunities for Antibiotic and Vaccine Development

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