Principles of selectivity and translocation in transition metal transporter

摘要

Abstract Transition metals, such as iron, copper, and zinc, are essential trace elements for life, playing fundamental catalytic, structural and signaling functions. Transmembrane transporters that regulate the vectorial metal uptake and extrusion across cellular membranes play a gatekeeper role in controlling metal homeostasis. Their activity guarantees that metal levels are tightly regulated to meet indispensable cellular requirements without reaching toxic levels. The parent MIRA project targets primary active transition metal pumps and solute carriers (SLC) towards: (i) investigating the principles of metal selectivity for first, second- and third- row transition metals and (ii) their metal coordination chemistry; (iii) determining the metal translocation pathway; (iv) addressing the mechanisms of energy transduction processes at a molecular level. We investigate known and novel transporter families involved in metal homeostasis and disease progression including: 1) P1B-type ATPases, primary active transporters controlling intracellular copper levels in humans, and modulating the concentrations of copper and other transition metals in pathogenic bacteria; 2) TMEM205, a novel human transporter involved in copper extrusion and anti-cancer Pt-complexes transport and resistance; 3) IroT transporters, putative iron-regulated solute carriers responsible for iron(II) acquisition and virulence in pathogenic prokaryotes. In this proposal we propose the acquisition of a Biacore T200 Surface Plasmon Resonance instrument to identify and characterize the interactions between transporters and molecular partners responsible for metal delivery and uptake to/from the investigated transporters. This instrumentation will be utilized to quantitatively determine kinetic, affinity, specificity, selectivity, and thermodynamic parameters of biomolecular interactions with metal- chaperone donors/acceptors, and screen small molecule libraries to identify novel transporter modulators. The unit features a sample recovery modality in the analyte dissociation phase and will be integrated in a proteomic and metallomic workflow to allow identification, characterization and metal speciation of novel binders from cell extracts and fractionated lysates. The implementation of this instrument in our experimental workflow is expected to provide unprecedented molecular insights in key pathways responsible for metal delivery and activation of transmembrane metal transporters in prokaryotes and eukaryotes.