Uracil/H+ symport by FurE refines aspects of the rocking-bundle mechanism of APC-type transporters

Zantza, Iliana; Pyrris, Yiannis; Raniolo, Stefano; Papadaki, Georgia F.; Lambrinidis, George; Limongelli, Vittorio; Diallinas, George; Mikros, Emmanuel

doi:10.1016/j.jmb.2023.168226

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Journal article

Uracil/H+ symport by FurE refines aspects of the rocking-bundle mechanism of APC-type transporters

Zantza, Iliana Department of Pharmacy, National and Kapodistrian University of Athens, Panepistimiopolis, Greece
Pyrris, Yiannis Department of Biology, National and Kapodistrian University of Athens, Panepistimiopolis, Greece
Raniolo, Stefano ORCID Euler Institute (EUL), Università della Svizzera italiana, Switzerland
Papadaki, Georgia F. Department of Biology, National and Kapodistrian University of Athens, Panepistimiopolis, Greece
Lambrinidis, George Department of Pharmacy, National and Kapodistrian University of Athens, Panepistimiopolis, Greece
Limongelli, Vittorio ORCID Euler Institute (EUL), Università della Svizzera italiana, Switzerland ; Department of Pharmacy, University of Naples “Federico II”, Naples, Italy
Diallinas, George Department of Biology, National and Kapodistrian University of Athens, Panepistimiopolis, Greece ; Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Heraklion, Greece
Mikros, Emmanuel Department of Pharmacy, National and Kapodistrian University of Athens, Panepistimiopolis, Greece ; Athena Research and Innovation Center in Information Communication & Knowledge Technologies, Marousi, Greece

2023

Published in:

Journal of molecular biology. - 2023, vol. 435, no. 19, p. 168226

FurE nucleobase-proton symporter

English 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 rational mutational analysis. Our study reveals a stepwise, induced-fit, mechanism of ordered sequential transport of proton and uracil, which in turn suggests that FurE, functions as a multi-step gated pore, rather than employing ‘rocking’ of compact domains, as often proposed for APC transporters. Finally, our work supports that specific residues of the cytoplasmic N-tail are involved in substrate translocation, in line with their essentiality for FurE function.

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