Modulation of the Neisseria gonorrhoeae drug efflux conduit MtrE

• Published in: Scientific reports 2017-12, Vol.7 (1), p.17091-10, Article 17091
• Main Authors: Tamburrino, Giulia, Llabrés, Salomé, Vickery, Owen N., Pitt, Samantha J., Zachariae, Ulrich
• Format: Article
• Language: English
• Subjects: 631/154/555; 631/57/2266; 631/57/2283; Antibiotic resistance; Antibiotics; Bacteria; Bacterial infections; Bacterial Outer Membrane Proteins - chemistry; Bacterial Outer Membrane Proteins - genetics; Bacterial Outer Membrane Proteins - metabolism; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Cations; Cell division; Computer applications; Conductance; Crystal structure; Drug Resistance, Multiple, Bacterial; Electrophysiological Phenomena; Electrophysiology; Fusion protein; Gram-negative bacteria; Humanities and Social Sciences; Lipid Bilayers - chemistry; Lipid Bilayers - metabolism; Lipids; Lipoproteins - chemistry; Lipoproteins - genetics; Lipoproteins - metabolism; Membrane fusion; Membrane proteins; Membrane Transport Proteins - chemistry; Membrane Transport Proteins - genetics; Membrane Transport Proteins - metabolism; Molecular Dynamics Simulation; multidisciplinary; Neisseria gonorrhoeae; Neisseria gonorrhoeae - metabolism; Patch-Clamp Techniques; Protein Structure, Tertiary; Proteins; Recombinant Proteins - biosynthesis; Recombinant Proteins - chemistry; Recombinant Proteins - isolation & purification; Science; Science (multidisciplinary)
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-16995-x

Widespread antibiotic resistance, especially of Gram-negative bacteria, has become a severe concern for human health. Tripartite efflux pumps are one of the major contributors to resistance in Gram-negative pathogens, by efficiently expelling a broad spectrum of antibiotics from the organism. In Neisseria gonorrhoeae , one of the first bacteria for which pan-resistance has been reported, the most expressed efflux complex is MtrCDE. Here we present the electrophysiological characterisation of the outer membrane component MtrE and the membrane fusion protein MtrC, obtained by a combination of planar lipid bilayer recordings and in silico techniques. Our in vitro results show that MtrE can be regulated by periplasmic binding events and that the interaction between MtrE and MtrC is sufficient to stabilize this complex in an open state. In contrast to other efflux conduits, the open complex only displays a slight preference for cations. The maximum conductance we obtain in the in vitro recordings is comparable to that seen in our computational electrophysiology simulations conducted on the MtrE crystal structure, indicating that this state may reflect a physiologically relevant open conformation of MtrE. Our results suggest that the MtrC/E binding interface is an important modulator of MtrE function, which could potentially be targeted by new efflux inhibitors.