Zantza, I. | bioRxiv Science

bioRxiv2022

Molecular basis of uracil/H+ symport mechanism operated by the FurE/NCS1 transporter

Transporters mediate the uptake of solutes, metabolites and drugs across the cell membrane. The eukaryotic FurE nucleobase/H+ symporter of Aspergillus nidulans has been used as a model protein to address structure-function relationships in the APC transporter superfamily, members of which are characterized by the LeuT-fold and seem to operate by the so-called rocking-bundle mechanism. In this study, we reveal the binding mode, translocation and release pathway of uracil/H+ by FurE, using path collective variable, funnel metadynamics and rationally designed mutational analysis. Our study reveals a step-wise, induced-fit, mechanism of ordered sequential transport of proton and uracil, which in turn suggests that the FurE symporter, and probably structurally similar transporters, functions as a multi-step gated pore, rather than employing rocking of compact domains, as generally proposed for APC transporters. In addition, our work further supports the emerging concept that specific elements of cytosolic terminal regions of transporters might be functionally important.

molecular biology↗

bioRxiv2018

Hydroxytyrosol (HT) analogues act as potent antifungals by direct disruption of the fungal cell membrane

Fungal infections constitute an emerging threat and a prevalent health problem due to increasing number of immunocompromised people and pharmacological or other treatments aiming at viral infections, cancer or allergies. Currently used antifungals suffer from inefficiency, toxic side effects and developing drug-resistance. Additionally, over the last two decades no new classes of antifungals have been approved, emphasizing the urgent need for developing a novel generation of antifungals. Here we investigate the antifungal activity of a series of chemically synthesized Hydroxytyrosol (HT) analogues. HT is one of the major phenolic compounds in olive oil, shown to possess radical-scavenging antioxidant, antiproliferative, proapoptotic and anti-inflammatory activities. No previous report has studied HT analogues as antifungals. We show that specific analogues have broad and strong antifungal activity, significantly stronger than the parent compound HT. Using A. nidulans as an in vivo cellular model system, we show that antifungal HT analogues have an unprecedented efficiency in fungal plasma membrane destruction. Importantly, antifungal HT analogues did not show toxicity in a mammalian cell line, whereas no resistance to HT analogues was obtained by standard mutagenesis. Our results open the way for the development of a novel, efficient and safer class of antifungals.

microbiology↗