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Abeyrathna SS, Abeyrathna NS, Basak P, Irvine GW, Zhang L, Meloni G. Plastic recognition and electrogenic uniport translocation of 1 st-, 2 nd-, and 3 rd-row transition and post-transition metals by primary-active transmembrane P 1B-2-type ATPase pumps. Chem Sci 2023; 14:6059-6078. [PMID: 37293658 PMCID: PMC10246665 DOI: 10.1039/d3sc00347g] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 05/10/2023] [Indexed: 06/10/2023] Open
Abstract
Transmembrane P1B-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(ii)-pumps of the P1B-2-type subclass, in addition to Zn2+, select diverse metals (Pb2+, Cd2+ and Hg2+) 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(ii)-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(ii)-pumps are electrogenic uniporters that preserve the transport mechanism with 1st-, 2nd- and 3rd-row transition metal substrates. Promiscuous coordination plasticity, guarantees diverse, yet defined, cargo selectivity coupled to their translocation.
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Affiliation(s)
- Sameera S Abeyrathna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Nisansala S Abeyrathna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Priyanka Basak
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Gordon W Irvine
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Limei Zhang
- Department of Biochemistry and Redox Biology Center and the Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln Lincoln NE 68588 USA
| | - Gabriele Meloni
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
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Li P, Nayeri N, Górecki K, Becares ER, Wang K, Mahato DR, Andersson M, Abeyrathna SS, Lindkvist‐Petersson K, Meloni G, Missel JW, Gourdon P. PcoB is a defense outer membrane protein that facilitates cellular uptake of copper. Protein Sci 2022; 31:e4364. [PMID: 35762724 PMCID: PMC9210255 DOI: 10.1002/pro.4364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/03/2022] [Accepted: 05/27/2022] [Indexed: 01/17/2023]
Abstract
Copper (Cu) is one of the most abundant trace metals in all organisms, involved in a plethora of cellular processes. Yet elevated concentrations of the element are harmful, and interestingly prokaryotes are more sensitive for environmental Cu stress than humans. Various transport systems are present to maintain intracellular Cu homeostasis, including the prokaryotic plasmid-encoded multiprotein pco operon, which is generally assigned as a defense mechanism against elevated Cu concentrations. Here we structurally and functionally characterize the outer membrane component of the Pco system, PcoB, recovering a 2.0 Å structure, revealing a classical β-barrel architecture. Unexpectedly, we identify a large opening on the extracellular side, linked to a considerably electronegative funnel that becomes narrower towards the periplasm, defining an ion-conducting pathway as also supported by metal binding quantification via inductively coupled plasma mass spectrometry and molecular dynamics (MD) simulations. However, the structure is partially obstructed towards the periplasmic side, and yet flux is permitted in the presence of a Cu gradient as shown by functional characterization in vitro. Complementary in vivo experiments demonstrate that isolated PcoB confers increased sensitivity towards Cu. Aggregated, our findings indicate that PcoB serves to permit Cu import. Thus, it is possible the Pco system physiologically accumulates Cu in the periplasm as a part of an unorthodox defense mechanism against metal stress. These results point to a previously unrecognized principle of maintaining Cu homeostasis and may as such also assist in the understanding and in efforts towards combatting bacterial infections of Pco-harboring pathogens.
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Affiliation(s)
- Ping Li
- Department of Experimental Medical ScienceLund UniversityLundSweden
| | - Niloofar Nayeri
- Department of Experimental Medical ScienceLund UniversityLundSweden
| | - Kamil Górecki
- Department of Experimental Medical ScienceLund UniversityLundSweden
| | - Eva Ramos Becares
- Department of Biomedical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Kaituo Wang
- Department of Biomedical SciencesUniversity of CopenhagenCopenhagenDenmark
| | | | | | - Sameera S. Abeyrathna
- Department of Chemistry and BiochemistryThe University of Texas at DallasRichardsonTexasUSA
| | | | - Gabriele Meloni
- Department of Chemistry and BiochemistryThe University of Texas at DallasRichardsonTexasUSA
| | | | - Pontus Gourdon
- Department of Experimental Medical ScienceLund UniversityLundSweden
- Department of Biomedical SciencesUniversity of CopenhagenCopenhagenDenmark
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Abeyrathna NS, Abeyrathna SS, Meloni G. Metal Substrate Translocation and Transport Mechanism of the
Sinorhizobium meliloti
P
1B
‐
5
‐type ATPase Nia Revealed by
In‐vitro
Transport Assays in Proteoliposomes. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r3958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Gabriele Meloni
- Chemistry and BiochemistryThe University of Texas at DallasRichardsonTX
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Herbert FC, Abeyrathna SS, Abeyrathna NS, Wijesundara YH, Brohlin OR, Carraro F, Amenitsch H, Falcaro P, Luzuriaga MA, Durand-Silva A, Diwakara SD, Smaldone RA, Meloni G, Gassensmith JJ. Stabilization of supramolecular membrane protein-lipid bilayer assemblies through immobilization in a crystalline exoskeleton. Nat Commun 2021; 12:2202. [PMID: 33850135 PMCID: PMC8044103 DOI: 10.1038/s41467-021-22285-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 02/25/2021] [Indexed: 11/09/2022] Open
Abstract
Artificial native-like lipid bilayer systems constructed from phospholipids assembling into unilamellar liposomes allow the reconstitution of detergent-solubilized transmembrane proteins into supramolecular lipid-protein assemblies called proteoliposomes, which mimic cellular membranes. Stabilization of these complexes remains challenging because of their chemical composition, the hydrophobicity and structural instability of membrane proteins, and the lability of interactions between protein, detergent, and lipids within micelles and lipid bilayers. In this work we demonstrate that metastable lipid, protein-detergent, and protein-lipid supramolecular complexes can be successfully generated and immobilized within zeolitic-imidazole framework (ZIF) to enhance their stability against chemical and physical stressors. Upon immobilization in ZIF bio-composites, blank liposomes, and model transmembrane metal transporters in detergent micelles or embedded in proteoliposomes resist elevated temperatures, exposure to chemical denaturants, aging, and mechanical stresses. Extensive morphological and functional characterization of the assemblies upon exfoliation reveal that all these complexes encapsulated within the framework maintain their native morphology, structure, and activity, which is otherwise lost rapidly without immobilization.
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Affiliation(s)
- Fabian C Herbert
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Sameera S Abeyrathna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Nisansala S Abeyrathna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Yalini H Wijesundara
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Olivia R Brohlin
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Francesco Carraro
- Institute of Physical and Theoretical Chemistry, Graz University of Technology, Graz, Austria
| | - Heinz Amenitsch
- Institute of Inorganic Chemistry, Graz University of Technology, Graz, Austria
| | - Paolo Falcaro
- Institute of Physical and Theoretical Chemistry, Graz University of Technology, Graz, Austria
| | - Michael A Luzuriaga
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Alejandra Durand-Silva
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Shashini D Diwakara
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Ronald A Smaldone
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Gabriele Meloni
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA.
| | - Jeremiah J Gassensmith
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA.
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA.
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Tutol JN, Lee J, Chi H, Faizuddin FN, Abeyrathna SS, Zhou Q, Morcos F, Meloni G, Dodani SC. A single point mutation converts a proton-pumping rhodopsin into a red-shifted, turn-on fluorescent sensor for chloride. Chem Sci 2021; 12:5655-5663. [PMID: 34163777 PMCID: PMC8179538 DOI: 10.1039/d0sc06061e] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 03/08/2021] [Indexed: 12/11/2022] Open
Abstract
The visualization of chloride in living cells with fluorescent sensors is linked to our ability to design hosts that can overcome the energetic penalty of desolvation to bind chloride in water. Fluorescent proteins can be used as biological supramolecular hosts to address this fundamental challenge. Here, we showcase the power of protein engineering to convert the fluorescent proton-pumping rhodopsin GR from Gloeobacter violaceus into GR1, a red-shifted, turn-on fluorescent sensor for chloride in detergent micelles and in live Escherichia coli. This non-natural function was unlocked by mutating D121, which serves as the counterion to the protonated retinylidene Schiff base chromophore. Substitution from aspartate to valine at this position (D121V) creates a binding site for chloride. The binding of chloride tunes the pK a of the chromophore towards the protonated, fluorescent state to generate a pH-dependent response. Moreover, ion pumping assays combined with bulk fluorescence and single-cell fluorescence microscopy experiments with E. coli, expressing a GR1 fusion with a cyan fluorescent protein, show that GR1 does not pump ions nor sense membrane potential but instead provides a reversible, ratiometric readout of changes in extracellular chloride at the membrane. This discovery sets the stage to use natural and laboratory-guided evolution to build a family of rhodopsin-based fluorescent chloride sensors with improved properties for cellular applications and learn how proteins can evolve and adapt to bind anions in water.
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Affiliation(s)
- Jasmine N Tutol
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Jessica Lee
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
- Department of Biological Sciences, The University of Texas at Dallas Richardson TX 75080 USA
| | - Hsichuan Chi
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
- Department of Biological Sciences, The University of Texas at Dallas Richardson TX 75080 USA
| | - Farah N Faizuddin
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
- Department of Biological Sciences, The University of Texas at Dallas Richardson TX 75080 USA
| | - Sameera S Abeyrathna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Qin Zhou
- Department of Biological Sciences, The University of Texas at Dallas Richardson TX 75080 USA
| | - Faruck Morcos
- Department of Biological Sciences, The University of Texas at Dallas Richardson TX 75080 USA
- Department of Bioengineering, The University of Texas at Dallas Richardson TX 75080 USA
| | - Gabriele Meloni
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Sheel C Dodani
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
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Abeyrathna SS, Abeyrathna NS, Thai NK, Sarkar P, D'Arcy S, Meloni G. IroT/MavN Is a Legionella Transmembrane Fe(II) Transporter: Metal Selectivity and Translocation Kinetics Revealed by in Vitro Real-Time Transport. Biochemistry 2019; 58:4337-4342. [PMID: 31589416 DOI: 10.1021/acs.biochem.9b00658] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In intravacuolar pathogens, iron is essential for growth and virulence. In Legionella pneumophila, a putative transmembrane protein inserted on the surface of the host pathogen-containing vacuole, IroT/MavN, facilitates intravacuolar iron acquisition from the host by an unknown mechanism, bypassing the problem of Fe(III) insolubility and mobilization. We developed a platform for purification and reconstitution of IroT in artificial lipid bilayer vesicles (proteoliposomes). By encapsulating the fluorescent reporter probe Fluozin-3, we reveal, by real-time metal transport assays, that IroT is a high-affinity iron transporter selective for Fe(II) over other essential transition metals. Mutational analysis reveals important residues in the transmembrane helices, soluble domains, and loops important for substrate recognition and translocation. The work establishes the substrate transport properties in a novel transporter family important for iron acquisition at the host-pathogen intravacuolar interface and provides chemical tools for a comparative investigation of the translocation properties in other iron transporter families.
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Affiliation(s)
- Sameera S Abeyrathna
- Department of Chemistry and Biochemistry , The University of Texas at Dallas , Richardson , Texas 75080 , United States
| | - Nisansala S Abeyrathna
- Department of Chemistry and Biochemistry , The University of Texas at Dallas , Richardson , Texas 75080 , United States
| | - Nathan Khoi Thai
- Department of Chemistry and Biochemistry , The University of Texas at Dallas , Richardson , Texas 75080 , United States
| | - Prithwijit Sarkar
- Department of Biological Sciences , The University of Texas at Dallas , Richardson , Texas 75080 , United States
| | - Sheena D'Arcy
- Department of Chemistry and Biochemistry , The University of Texas at Dallas , Richardson , Texas 75080 , United States.,Department of Biological Sciences , The University of Texas at Dallas , Richardson , Texas 75080 , United States
| | - Gabriele Meloni
- Department of Chemistry and Biochemistry , The University of Texas at Dallas , Richardson , Texas 75080 , United States
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