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Your search keyword '"Marie-Louise R. Francis"' showing total 4 results
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4 results on '"Marie-Louise R. Francis"'

1. The anti-sigma factor RsrA responds to oxidative stress by reburying its hydrophobic core

Author

Karthik V. Rajasekar, Konrad Zdanowski, Jun Yan, Jonathan T. S. Hopper, Marie-Louise R. Francis, Colin Seepersad, Connor Sharp, Ludovic Pecqueur, Jörn M. Werner, Carol V. Robinson, Shabaz Mohammed, Jennifer R. Potts, and Colin Kleanthous

Subjects
Science
Abstract

Counteracting oxidative stress is essential in all organisms. Here, the authors outline a mechanism used by actinomycete bacteria in which oxidation of zinc-binding RsrA blocks its interaction with σR by sequestering hydrophobic residues used to bind σRwithin its own core.

Published
2016
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2. Porin threading drives receptor disengagement and establishes active colicin transport through Escherichia coli OmpF

Author

Renata Kaminska, Natalya Lukoyanova, Boonyaporn Chinthammit, Emma Elliston, Colin Kleanthous, Melissa N. Webby, Marie-Louise R. Francis, and Nicholas G. Housden

Subjects
cryo‐electron microscopy, Models, Molecular, Protein Conformation, alpha-Helical, medicine.disease_cause, 0303 health sciences, biology, Escherichia coli Proteins, General Neuroscience, Articles, Translocon, Microbiology, Virology & Host Pathogen Interaction, Protein Transport, Colicin, Porin, Thermodynamics, lipids (amino acids, peptides, and proteins), Periplasmic Proteins, Bacterial outer membrane, Bacterial Outer Membrane Proteins, Protein Binding, Gram-negative bacteria, Colicins, Porins, outer membrane, Article, bacteriocins, General Biochemistry, Genetics and Molecular Biology, 03 medical and health sciences, Protein Domains, Bacteriocin, Escherichia coli, medicine, Protein Interaction Domains and Motifs, Molecular Biology, 030304 developmental biology, Binding Sites, General Immunology and Microbiology, 030306 microbiology, Cryoelectron Microscopy, Membrane Proteins, Membrane Transport Proteins, Gene Expression Regulation, Bacterial, biochemical phenomena, metabolism, and nutrition, biology.organism_classification, Membranes & Trafficking, Kinetics, Bacterial Outer Membrane, Gram‐negative bacteria, Colicin transport, Biophysics, bacteria, Protein Conformation, beta-Strand, fluorescent microscopy
Abstract

Bacteria deploy weapons to kill their neighbours during competition for resources and to aid survival within microbiomes. Colicins were the first such antibacterial system identified, yet how these bacteriocins cross the outer membrane (OM) of Escherichia coli is unknown. Here, by solving the structures of translocation intermediates via cryo‐EM and by imaging toxin import, we uncover the mechanism by which the Tol‐dependent nuclease colicin E9 (ColE9) crosses the bacterial OM. We show that threading of ColE9’s disordered N‐terminal domain through two pores of the trimeric porin OmpF causes the colicin to disengage from its primary receptor, BtuB, and reorganises the translocon either side of the membrane. Subsequent import of ColE9 through the lumen of a single OmpF subunit is driven by the proton‐motive force, which is delivered by the TolQ‐TolR‐TolA‐TolB assembly. Our study answers longstanding questions, such as why OmpF is a better translocator than OmpC, and reconciles the mechanisms by which both Tol‐ and Ton‐dependent bacteriocins cross the bacterial outer membrane., Cryo‐EM structures and fluorescence imaging reveal how the Tol‐dependent bacteriocin ColE9 crosses the outer bacterial membrane to exert microbial killing.

Published
2021
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3. Passive receptor dissociation driven by porin threading establishes active colicin transport through Escherichia coli OmpF

Author

Colin Kleanthous, Marie-Louise R. Francis, Natalya Lukoyanova, Nicholas G. Housden, Renata Kaminska, Emma Elliston, Melissa N. Webby, and Chinthammit B

Subjects
Chemistry, biochemical phenomena, metabolism, and nutrition, medicine.disease_cause, Translocon, Bacteriocin, Colicin transport, Colicin, Porin, medicine, Biophysics, bacteria, lipids (amino acids, peptides, and proteins), Threading (protein sequence), Bacterial outer membrane, Escherichia coli
Abstract

SUMMARYBacteria deploy weapons to kill their neighbours during competition for resources and aid survival within microbiomes. Colicins were the first antibacterial system identified yet how these bacteriocins cross the outer membrane of Escherichia coli is unknown. Here, by solving the structures of translocation intermediates and imaging toxin import, we uncover the mechanism by which the Tol-dependent nuclease colicin E9 (ColE9) crosses the outer membrane. We show that threading of ColE9’s disordered domain through two pores of the trimeric porin OmpF causes the colicin to disengage from its primary receptor, BtuB, and reorganise the translocon either side of the membrane. These rearrangements prime the toxin for import through the lumen of a single OmpF subunit, which is driven by the proton motive force-linked TolQ-TolR-TolA-TolB assembly. Our study explains why OmpF is a better translocator than OmpC and reconciles the mechanisms by which Ton- and Tol- dependent bacteriocins cross the bacterial outer membrane.

Published
2021
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