Evidence for a 'trap-and-flip' mechanism in a proton-dependent lipid transporter

  • Transport of lipids across membranes is fundamental for diverse biological pathways in cells. Multiple ion-coupled transporters participate in lipid translocation, but their mechanisms remain largely unknown. Major facilitator superfamily (MFS) lipid transporters play central roles in cell wall synthesis, brain development and function, lipids recycling, and cell signaling. Recent structures of MFS lipid transporters revealed overlapping architectural features pointing towards a common mechanism. Here we used cysteine disulfide trapping, molecular dynamics simulations, mutagenesis analysis, and transport assays in vitro and in vivo, to investigate the mechanism of LtaA, a proton-dependent MFS lipid transporter essential for lipoteichoic acids synthesis in the pathogen Staphylococcus aureus. We reveal that LtaA displays asymmetric lateral openings with distinct functional relevance and that cycling through outward- and inward-facing conformations is essential for transport activity. We demonstrate that while the entire amphipathic central cavity of LtaA contributes to lipid binding, its hydrophilic pocket dictates substrate specificity. We propose that LtaA catalyzes lipid translocation by a ‘trap-and-flip’ mechanism that might be shared among MFS lipid transporters.

Download full text files

Export metadata

Additional Services

Share in Twitter Search Google Scholar
Author:Elisabeth LambertORCiDGND, Ahmad Reza MehdipourORCiDGND, Alexander SchmidtORCiDGND, Gerhard HummerORCiD, Camilo PérezORCiDGND
Parent Title (English):bioRxiv
Document Type:Preprint
Date of Publication (online):2021/08/05
Date of first Publication:2021/08/05
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2023/04/07
Page Number:31
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
Licence (German):License LogoCreative Commons - CC BY-ND - Namensnennung - Keine Bearbeitungen 4.0 International