Plastic recognition and electrogenic uniport translocation of 1st-, 2nd-, and 3rd-row transition and post-transition metals by primary-active transmembrane P_1B-2-type ATPase pumps

Authors

Sameera S. Abeyrathna, The University of Texas at Dallas
Nisansala S. Abeyrathna, The University of Texas at Dallas
Priyanka Basak, The University of Texas at Dallas
Gordon W. Irvine, The University of Texas at Dallas
LiMei Zhang, University of Nebraska - LincolnFollow
Gabriele Meloni, The University of Texas at Dallas

Date of this Version

2023

Citation

Chem. Sci., 2023, 14, 6059-6078.

DOI: 10.1039/d3sc00347g

Comments

Open access. © 2023 The Author(s). Published by the Royal Society of Chemistry

Abstract

Transmembrane P-type ATPase pumps catalyze the extrusion of transition metal ions across cellular lipid membranes to maintain essential cellular metal homeostasis and detoxify toxic metals. Zn()-pumps of the P-type subclass, in addition to Zn , select diverse metals (Pb, Cdand Hg) at their transmembrane binding site and feature promiscuous metal-dependent ATP hydrolysis in the presence of these metals. Yet, a comprehensive understanding of the transport of these metals, their relative translocation rates, and transport mechanism remain elusive. We developed a platform for the characterization of primary-active Zn()-pumps in proteoliposomes to study metal selectivity, translocation events and transport mechanism in real-time, employing a “multi-probe” approach with fluorescent sensors responsive to diverse stimuli (metals, pH and membrane potential). Together with atomic-resolution investigation of cargo selection by X-ray absorption spectroscopy (XAS), we demonstrate that Zn()-pumps are electrogenic uniporters that preserve the transport mechanism with 1-, 2- and 3-row transition metal substrates. Promiscuous coordination plasticity, guarantees diverse, yet defined, cargo selectivity coupled to their translocation.