A two-lane mechanism for selective biological ammonium transport

Williamson, G.; Tamburrino, G.; Dias Mirandela, G.; Boeckstaens, M.; Bade, M.; Pisliakov, A.; Ives, C. M.; Terras, E.; Bizior, A.; Hoskisson, P. A.; Marini, A.-M.; Zachariae, U.; Javelle, A.

doi:10.1101/849562

bioRxiv · 10.1101/849562

A two-lane mechanism for selective biological ammonium transport

Williamson, G.·Tamburrino, G.·Dias Mirandela, G.·Boeckstaens, M.·Bade, M.·Pisliakov, A.·Ives, C. M.·Terras, E.·Bizior, A.·Hoskisson, P. A.·Marini, A.-M.·Zachariae, U.·Javelle, A.

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Abstract

The transport of charged molecules across biological membranes faces the dual problem of accommodating charges in a highly hydrophobic environment while maintaining selective substrate translocation. A particular controversy has existed around the mechanism of ammonium exchange by the ubiquitous Amt/Mep/Rh transporter family, an essential process in all kingdoms of life. Here, using a combination of electrophysiology, yeast functional complementation and extended molecular dynamics simulations, we reveal a unique two-lane pathway for electrogenic NH4+ transport in two archetypal members of the family. The pathway underpins a mechanism by which charged H+ and neutral NH3 are carried separately across the membrane after NH4+ deprotonation. This mechanism defines a new principle of achieving transport selectivity against competing ions in a biological transport process.

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Williamson, G., Tamburrino, G., Dias Mirandela, G., Boeckstaens, M., Bade, M., Pisliakov, A., Ives, C. M., Terras, E., Bizior, A., Hoskisson, P. A., Marini, A.-M., Zachariae, U., Javelle, A.. 2019-11-20. A two-lane mechanism for selective biological ammonium transport. https://doi.org/10.1101/849562

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