1
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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] [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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2
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Yang GM, Xu L, Wang RM, Tao X, Zheng ZW, Chang S, Ma D, Zhao C, Dong Y, Wu S, Guo J, Wu ZY. Structures of the human Wilson disease copper transporter ATP7B. Cell Rep 2023; 42:112417. [PMID: 37074913 DOI: 10.1016/j.celrep.2023.112417] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 02/22/2023] [Accepted: 04/05/2023] [Indexed: 04/20/2023] Open
Abstract
The P-type ATPase ATP7B exports cytosolic copper and plays an essential role in the regulation of cellular copper homeostasis. Mutants of ATP7B cause Wilson disease (WD), an autosomal recessive disorder of copper metabolism. Here, we present cryoelectron microscopy (cryo-EM) structures of human ATP7B in the E1 state in the apo, the putative copper-bound, and the putative cisplatin-bound forms. In ATP7B, the N-terminal sixth metal-binding domain (MBD6) binds at the cytosolic copper entry site of the transmembrane domain (TMD), facilitating the delivery of copper from the MBD6 to the TMD. The sulfur-containing residues in the TMD of ATP7B mark the copper transport pathway. By comparing structures of the E1 state human ATP7B and E2-Pi state frog ATP7B, we propose the ATP-driving copper transport model of ATP7B. These structures not only advance our understanding of the mechanisms of ATP7B-mediated copper export but can also guide the development of therapeutics for the treatment of WD.
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Affiliation(s)
- Guo-Min Yang
- Department of Medical Genetics and Center for Rare Diseases, and Department of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China
| | - Lingyi Xu
- Department of Biophysics, and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Rou-Min Wang
- Department of Medical Genetics and Center for Rare Diseases, and Department of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China
| | - Xin Tao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Zi-Wei Zheng
- Department of Medical Genetics and Center for Rare Diseases, and Department of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China
| | - Shenghai Chang
- Department of Biophysics, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Center of Cryo Electron Microscopy, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Demin Ma
- Department of Biophysics, and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Cheng Zhao
- Department of Biophysics, and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yi Dong
- Department of Medical Genetics and Center for Rare Diseases, and Department of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China
| | - Shan Wu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, Hubei 430062, China.
| | - Jiangtao Guo
- Department of Biophysics, and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China; Department of Cardiology, Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310016, China; Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310058, China; Liangzhu Laboratory, Zhejiang University Medical Center, 1369 West Wenyi Road, Hangzhou, Zhejiang 311121, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Science and Brain-machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, China.
| | - Zhi-Ying Wu
- Department of Medical Genetics and Center for Rare Diseases, and Department of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China; Liangzhu Laboratory, Zhejiang University Medical Center, 1369 West Wenyi Road, Hangzhou, Zhejiang 311121, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Science and Brain-machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, China.
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3
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Orädd F, Steffen JH, Gourdon P, Andersson M. Copper binding leads to increased dynamics in the regulatory N-terminal domain of full-length human copper transporter ATP7B. PLoS Comput Biol 2022; 18:e1010074. [PMID: 36070320 PMCID: PMC9484656 DOI: 10.1371/journal.pcbi.1010074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 09/19/2022] [Accepted: 08/17/2022] [Indexed: 11/25/2022] Open
Abstract
ATP7B is a human copper-transporting P1B-type ATPase that is involved in copper homeostasis and resistance to platinum drugs in cancer cells. ATP7B consists of a copper-transporting core and a regulatory N-terminal tail that contains six metal-binding domains (MBD1-6) connected by linker regions. The MBDs can bind copper, which changes the dynamics of the regulatory domain and activates the protein, but the underlying mechanism remains unknown. To identify possible copper-specific structural dynamics involved in transport regulation, we constructed a model of ATP7B spanning the N-terminal tail and core catalytic domains and performed molecular dynamics (MD) simulations with (holo) and without (apo) copper ions bound to the MBDs. In the holo protein, MBD2, MBD3 and MBD5 showed enhanced mobilities, which resulted in a more extended N-terminal regulatory region. The observed separation of MBD2 and MBD3 from the core protein supports a mechanism where copper binding activates the ATP7B protein by reducing interactions among MBD1-3 and between MBD1-3 and the core protein. We also observed an increased interaction between MBD5 and the core protein that brought the copper-binding site of MBD5 closer to the high-affinity internal copper-binding site in the core protein. The simulation results assign specific, mechanistic roles to the metal-binding domains involved in ATP7B regulation that are testable in experimental settings. Living organisms depend upon active transport against gradients across biological membranes for survival. Such transport can be accomplished by ATP-dependent membrane protein transporters for which the activity must be regulated to maintain optimal concentrations in the cellular compartments. The regulatory mechanisms often involve structural responses inherent to the protein structure, which because of their dynamic nature can be hard to assess experimentally. A prime example is regulation of cellular copper levels by a copper-binding tail in the human copper transporter ATP7B. Dysregulation can cause severe diseases, for example the copper metabolism disorder Wilson’s disease, which is caused by mutations in ATP7B regulation machinery. Due to the practical difficulties in working with membrane proteins, most studies of ATP7B have been conducted in the absence of the membrane-bound protein core. Here, we used computer simulations of full-length ATP7B to study how structural dynamics in the regulatory tail differ between copper-bound and copper-free states. Copper induced increased dynamics in the tail, resulting in an overall movement towards the ion-binding site in the protein core. The simulations identified several, hitherto not reported, interactions between the regulatory tail and the protein core that can be targeted experimentally to enhance our understanding of this medically relevant regulatory mechanism.
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Affiliation(s)
- Fredrik Orädd
- Department of Chemistry, Umeå University, Umeå, Sweden
| | - Jonas Hyld Steffen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Pontus Gourdon
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Experimental Medical Science, Lund University, Lund, Sweden
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4
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Salustros N, Grønberg C, Abeyrathna NS, Lyu P, Orädd F, Wang K, Andersson M, Meloni G, Gourdon P. Structural basis of ion uptake in copper-transporting P 1B-type ATPases. Nat Commun 2022; 13:5121. [PMID: 36045128 PMCID: PMC9433437 DOI: 10.1038/s41467-022-32751-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 08/16/2022] [Indexed: 11/30/2022] Open
Abstract
Copper is essential for living cells, yet toxic at elevated concentrations. Class 1B P-type (P1B-) ATPases are present in all kingdoms of life, facilitating cellular export of transition metals including copper. P-type ATPases follow an alternating access mechanism, with inward-facing E1 and outward-facing E2 conformations. Nevertheless, no structural information on E1 states is available for P1B-ATPases, hampering mechanistic understanding. Here, we present structures that reach 2.7 Å resolution of a copper-specific P1B-ATPase in an E1 conformation, with complementing data and analyses. Our efforts reveal a domain arrangement that generates space for interaction with ion donating chaperones, and suggest a direct Cu+ transfer to the transmembrane core. A methionine serves a key role by assisting the release of the chaperone-bound ion and forming a cargo entry site together with the cysteines of the CPC signature motif. Collectively, the findings provide insights into P1B-mediated transport, likely applicable also to human P1B-members.
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Affiliation(s)
- Nina Salustros
- Department of Biomedical Sciences, Copenhagen University, Maersk Tower 7-9, Nørre Allé 14, DK-2200, Copenhagen, Denmark
| | - Christina Grønberg
- Department of Biomedical Sciences, Copenhagen University, Maersk Tower 7-9, Nørre Allé 14, DK-2200, Copenhagen, Denmark
| | - Nisansala S Abeyrathna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800W Campbell Rd., Richardson, TX, 75080, USA
| | - Pin Lyu
- Department of Biomedical Sciences, Copenhagen University, Maersk Tower 7-9, Nørre Allé 14, DK-2200, Copenhagen, Denmark
- Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen, Denmark
| | - Fredrik Orädd
- Department of Chemistry, Umeå University, Linneaus Väg 10, SE-901 87, Umeå, Sweden
| | - Kaituo Wang
- Department of Biomedical Sciences, Copenhagen University, Maersk Tower 7-9, Nørre Allé 14, DK-2200, Copenhagen, Denmark
| | - Magnus Andersson
- Department of Chemistry, Umeå University, Linneaus Väg 10, SE-901 87, Umeå, Sweden
| | - Gabriele Meloni
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800W Campbell Rd., Richardson, TX, 75080, USA
| | - Pontus Gourdon
- Department of Biomedical Sciences, Copenhagen University, Maersk Tower 7-9, Nørre Allé 14, DK-2200, Copenhagen, Denmark.
- Department of Experimental Medical Science, Lund University, Sölvegatan 19, SE-221 84, Lund, Sweden.
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5
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Placenti MA, Roman EA, González Flecha FL, González-Lebrero RM. Functional characterization of Legionella pneumophila Cu + transport ATPase. The activation by Cu + and ATP. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183822. [PMID: 34826402 DOI: 10.1016/j.bbamem.2021.183822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 11/08/2021] [Accepted: 11/17/2021] [Indexed: 06/13/2023]
Abstract
Cu+-ATPases are integral membrane proteins belonging to the IB subfamily of the P-type ATPases that couple Cu+ transport to the hydrolysis of ATP. As some structural and functional particularities arise for Cu+-ATPases, several authors suggest that some of the reaction steps of the Albers-Post model postulated for other P-ATPases may be different. In this work we describe a functional characterization of Legionella pneumophila Cu+-ATPase (LpCopA), the first PIB-ATPase whose structure was determined by X-ray crystallography. Cu+-ATPase activity of the enzyme presents a maximum at ∼37 °C and pH 6.6-6.8. Phospholipids enhance LpCopA Cu+-ATPase activity in a non-essential mode where optimal activity is achieved at an asolectin molar fraction of 0.15 and an amphiphile-protein ratio of ~30,000. As described for other P-ATPases, Mg2+ acts as an essential activator. Furthermore, Cu+-ATPase activity dependence on [Cu+] and [ATP] can both be described by a sum of two hyperbolic functions. Based on that, and the [Cu+] and [ATP] dependencies of the best fitting parameters of the hyperbolae pointed above, we propose a minimal reaction scheme for the catalytic mechanism that shares the basic reaction steps of the Albers-Post model for P-type ATPases. The reaction scheme postulated contemplates two different binding affinities for a single ATP (apparent affinities of 0.66 and 550 μM at [Cu+] → ∞) and binding of at least 2 Cu+ with different affinities as well (apparent affinities of 1.4 and 102.5 μM at [ATP] → ∞).
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Affiliation(s)
- M Agueda Placenti
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Química Biológica, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisicoquímica Biológicas, Buenos Aires, Argentina
| | - Ernesto A Roman
- Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisicoquímica Biológicas, Buenos Aires, Argentina; Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Buenos Aires, Argentina
| | - F Luis González Flecha
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Química Biológica, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisicoquímica Biológicas, Buenos Aires, Argentina.
| | - Rodolfo M González-Lebrero
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Química Biológica, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisicoquímica Biológicas, Buenos Aires, Argentina.
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6
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Grønberg C, Hu Q, Mahato DR, Longhin E, Salustros N, Duelli A, Lyu P, Bågenholm V, Eriksson J, Rao KU, Henderson DI, Meloni G, Andersson M, Croll T, Godaly G, Wang K, Gourdon P. Structure and ion-release mechanism of P IB-4-type ATPases. eLife 2021; 10:73124. [PMID: 34951590 PMCID: PMC8880997 DOI: 10.7554/elife.73124] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 12/17/2021] [Indexed: 11/13/2022] Open
Abstract
Transition metals, such as zinc, are essential micronutrients in all organisms, but also highly toxic in excessive amounts. Heavy-metal transporting P-type (PIB) ATPases are crucial for homeostasis, conferring cellular detoxification and redistribution through transport of these ions across cellular membranes. No structural information is available for the PIB-4-ATPases, the subclass with the broadest cargo scope, and hence even their topology remains elusive. Here we present structures and complementary functional analyses of an archetypal PIB‑4‑ATPase, sCoaT from Sulfitobacter sp. NAS14-1. The data disclose the architecture, devoid of classical so-called heavy metal binding domains, and provides fundamentally new insights into the mechanism and diversity of heavy-metal transporters. We reveal several novel P-type ATPase features, including a dual role in heavy-metal release and as an internal counter ion of an invariant histidine. We also establish that the turn-over of PIB‑ATPases is potassium independent, contrasting to many other P-type ATPases. Combined with new inhibitory compounds, our results open up for efforts in e.g. drug discovery, since PIB-4-ATPases function as virulence factors in many pathogens.
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Affiliation(s)
- Christina Grønberg
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen N, Denmark
| | - Qiaoxia Hu
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Elena Longhin
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nina Salustros
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen N, Denmark
| | - Annette Duelli
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen N, Denmark
| | - Pin Lyu
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen N, Denmark
| | - Viktoria Bågenholm
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen N, Denmark
| | | | | | | | - Gabriele Meloni
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, United States
| | | | - Tristan Croll
- Department of Haematology, University of Cambridge, Cambridge, United Kingdom
| | - Gabriela Godaly
- Department of Laboratory Medicine, Umeå University, Umeå, Sweden
| | - Kaituo Wang
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen N, Denmark
| | - Pontus Gourdon
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen N, Denmark
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7
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Andrei A, Di Renzo MA, Öztürk Y, Meisner A, Daum N, Frank F, Rauch J, Daldal F, Andrade SLA, Koch HG. The CopA2-Type P 1B-Type ATPase CcoI Serves as Central Hub for cbb 3-Type Cytochrome Oxidase Biogenesis. Front Microbiol 2021; 12:712465. [PMID: 34589071 PMCID: PMC8475189 DOI: 10.3389/fmicb.2021.712465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 07/12/2021] [Indexed: 11/13/2022] Open
Abstract
Copper (Cu)-transporting P1B-type ATPases are ubiquitous metal transporters and crucial for maintaining Cu homeostasis in all domains of life. In bacteria, the P1B-type ATPase CopA is required for Cu-detoxification and exports excess Cu(I) in an ATP-dependent reaction from the cytosol into the periplasm. CopA is a member of the CopA1-type ATPase family and has been biochemically and structurally characterized in detail. In contrast, less is known about members of the CopA2-type ATPase family, which are predicted to transport Cu(I) into the periplasm for cuproprotein maturation. One example is CcoI, which is required for the maturation of cbb 3-type cytochrome oxidase (cbb 3-Cox) in different species. Here, we reconstituted purified CcoI of Rhodobacter capsulatus into liposomes and determined Cu transport using solid-supported membrane electrophysiology. The data demonstrate ATP-dependent Cu(I) translocation by CcoI, while no transport is observed in the presence of a non-hydrolysable ATP analog. CcoI contains two cytosolically exposed N-terminal metal binding sites (N-MBSs), which are both important, but not essential for Cu delivery to cbb 3-Cox. CcoI and cbb 3-Cox activity assays in the presence of different Cu concentrations suggest that the glutaredoxin-like N-MBS1 is primarily involved in regulating the ATPase activity of CcoI, while the CopZ-like N-MBS2 is involved in Cu(I) acquisition. The interaction of CcoI with periplasmic Cu chaperones was analyzed by genetically fusing CcoI to the chaperone SenC. The CcoI-SenC fusion protein was fully functional in vivo and sufficient to provide Cu for cbb 3-Cox maturation. In summary, our data demonstrate that CcoI provides the link between the cytosolic and periplasmic Cu chaperone networks during cbb 3-Cox assembly.
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Affiliation(s)
- Andreea Andrei
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany.,Faculty of Biology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Maria Agostina Di Renzo
- Institute for Biochemistry, Faculty of Chemistry and Pharmacy, Albert-Ludwigs-University Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany.,Faculty of Chemistry and Pharmacy, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Yavuz Öztürk
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Alexandra Meisner
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Noel Daum
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Fabian Frank
- Institute for Biochemistry, Faculty of Chemistry and Pharmacy, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Juna Rauch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Fevzi Daldal
- Department of Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Susana L A Andrade
- Institute for Biochemistry, Faculty of Chemistry and Pharmacy, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Hans-Georg Koch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
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8
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Abeyrathna N, Abeyrathna S, Morgan MT, Fahrni CJ, Meloni G. Transmembrane Cu(I) P-type ATPase pumps are electrogenic uniporters. Dalton Trans 2021; 49:16082-16094. [PMID: 32469032 DOI: 10.1039/d0dt01380c] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cu(i) P-type ATPases are transmembrane primary active ion pumps that catalyze the extrusion of copper ions across cellular membranes. Their activity is critical in controlling copper levels in all kingdoms of life. Biochemical and structural characterization established the structural framework by which Cu-pumps perform their function. However, the details of the overall mechanism of transport (uniporter vs. cotransporter) and electrogenicity still remain elusive. In this work, we developed a platform to reconstitute the model Cu(i)-pump from E. coli (EcCopA) in artificial lipid bilayer small unilamellar vesicles (SUVs) to quantitatively characterize the metal substrate, putative counter-ions and charge translocation. By encapsulating in the liposome lumen fluorescence detector probes (CTAP-3, pyranine and oxonol VI) responsive to diverse stimuli (Cu(i), pH and membrane potential), we correlated substrate, secondary-ion translocation and charge movement events in EcCopA proteoliposomes. This platform centered on multiple fluorescence reporters allowed study of the mechanism and translocation kinetic parameters in real-time for wild-type EcCopA and inactive mutants. The maximal initial Cu(i) transport rate of 165 nmol Cu(i) mg-1 min-1 and KM, Cu(I) = 0.15 ± 0.07 μM was determined with this analysis. We reveal that Cu(i) pumps are primary-active uniporters and electrogenic. The Cu(i) translocation cycle does not require proton counter-transport resulting in electrogenic generation of transmembrane potential upon translocation of one Cu(i) per ATP hydrolysis cycle. Thus, mechanistic differences between Cu(i) pumps and other better characterized P-type ATPases are discussed. The platform opens the venue to study translocation events and mechanisms of transport in other transition metal P-type ATPase pumps.
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Affiliation(s)
- Nisansala Abeyrathna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX 75080, USA.
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9
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Kuo MT, Huang YF, Chou CY, Chen HHW. Targeting the Copper Transport System to Improve Treatment Efficacies of Platinum-Containing Drugs in Cancer Chemotherapy. Pharmaceuticals (Basel) 2021; 14:ph14060549. [PMID: 34201235 PMCID: PMC8227247 DOI: 10.3390/ph14060549] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/05/2021] [Accepted: 06/07/2021] [Indexed: 12/18/2022] Open
Abstract
The platinum (Pt)-containing antitumor drugs including cisplatin (cis-diamminedichloroplatinum II, cDDP), carboplatin, and oxaliplatin, have been the mainstay of cancer chemotherapy. These drugs are effective in treating many human malignancies. The major cell-killing target of Pt drugs is DNA. Recent findings underscored the important roles of Pt drug transport system in cancer therapy. While many mechanisms have been proposed for Pt-drug transport, the high-affinity copper transporter (hCtr1), Cu chaperone (Atox1), and Cu exporters (ATP7A and ATP7B) are also involved in cDDP transport, highlighting Cu homeostasis regulation in Pt-based cancer therapy. It was demonstrated that by reducing cellular Cu bioavailable levels by Cu chelators, hCtr1 is transcriptionally upregulated by transcription factor Sp1, which binds the promoters of Sp1 and hCtr1. In contrast, elevated Cu poisons Sp1, resulting in suppression of hCtr1 and Sp1, constituting the Cu-Sp1-hCtr1 mutually regulatory loop. Clinical investigations using copper chelator (trientine) in carboplatin treatment have been conducted for overcoming Pt drug resistance due in part to defective transport. While results are encouraging, future development may include targeting multiple steps in Cu transport system for improving the efficacies of Pt-based cancer chemotherapy. The focus of this review is to delineate the mechanistic interrelationships between Cu homeostasis regulation and antitumor efficacy of Pt drugs.
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Affiliation(s)
- Macus Tien Kuo
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA;
| | - Yu-Fang Huang
- Department of Obstetrics and Gynecology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan;
| | - Cheng-Yang Chou
- Department of Obstetrics and Gynecology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan;
- Correspondence: (C.-Y.C.); (H.H.W.C.)
| | - Helen H. W. Chen
- Department of Radiation Oncology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
- Center of Applied Nanomedicine, National Cheng Kung University, Tainan 701, Taiwan
- Correspondence: (C.-Y.C.); (H.H.W.C.)
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10
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Andrei A, Öztürk Y, Khalfaoui-Hassani B, Rauch J, Marckmann D, Trasnea PI, Daldal F, Koch HG. Cu Homeostasis in Bacteria: The Ins and Outs. MEMBRANES 2020; 10:E242. [PMID: 32962054 PMCID: PMC7558416 DOI: 10.3390/membranes10090242] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 09/11/2020] [Accepted: 09/15/2020] [Indexed: 12/16/2022]
Abstract
Copper (Cu) is an essential trace element for all living organisms and used as cofactor in key enzymes of important biological processes, such as aerobic respiration or superoxide dismutation. However, due to its toxicity, cells have developed elaborate mechanisms for Cu homeostasis, which balance Cu supply for cuproprotein biogenesis with the need to remove excess Cu. This review summarizes our current knowledge on bacterial Cu homeostasis with a focus on Gram-negative bacteria and describes the multiple strategies that bacteria use for uptake, storage and export of Cu. We furthermore describe general mechanistic principles that aid the bacterial response to toxic Cu concentrations and illustrate dedicated Cu relay systems that facilitate Cu delivery for cuproenzyme biogenesis. Progress in understanding how bacteria avoid Cu poisoning while maintaining a certain Cu quota for cell proliferation is of particular importance for microbial pathogens because Cu is utilized by the host immune system for attenuating pathogen survival in host cells.
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Affiliation(s)
- Andreea Andrei
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
- Fakultät für Biologie, Albert-Ludwigs Universität Freiburg; Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Yavuz Öztürk
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
| | | | - Juna Rauch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
| | - Dorian Marckmann
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
| | | | - Fevzi Daldal
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Hans-Georg Koch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
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11
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Tadini-Buoninsegni F. Protein Adsorption on Solid Supported Membranes: Monitoring the Transport Activity of P-Type ATPases. Molecules 2020; 25:molecules25184167. [PMID: 32933017 PMCID: PMC7570688 DOI: 10.3390/molecules25184167] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 02/07/2023] Open
Abstract
P-type ATPases are a large family of membrane transporters that are found in all forms of life. These enzymes couple ATP hydrolysis to the transport of various ions or phospholipids across cellular membranes, thereby generating and maintaining crucial electrochemical potential gradients. P-type ATPases have been studied by a variety of methods that have provided a wealth of information about the structure, function, and regulation of this class of enzymes. Among the many techniques used to investigate P-type ATPases, the electrical method based on solid supported membranes (SSM) was employed to investigate the transport mechanism of various ion pumps. In particular, the SSM method allows the direct measurement of charge movements generated by the ATPase following adsorption of the membrane-bound enzyme on the SSM surface and chemical activation by a substrate concentration jump. This kind of measurement was useful to identify electrogenic partial reactions and localize ion translocation in the reaction cycle of the membrane transporter. In the present review, we discuss how the SSM method has contributed to investigate some key features of the transport mechanism of P-type ATPases, with a special focus on sarcoplasmic reticulum Ca2+-ATPase, mammalian Cu+-ATPases (ATP7A and ATP7B), and phospholipid flippase ATP8A2.
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12
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Tadini-Buoninsegni F, Palchetti I. Label-Free Bioelectrochemical Methods for Evaluation of Anticancer Drug Effects at a Molecular Level. SENSORS 2020; 20:s20071812. [PMID: 32218227 PMCID: PMC7181070 DOI: 10.3390/s20071812] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/19/2020] [Accepted: 03/21/2020] [Indexed: 02/06/2023]
Abstract
Cancer is a multifactorial family of diseases that is still a leading cause of death worldwide. More than 100 different types of cancer affecting over 60 human organs are known. Chemotherapy plays a central role for treating cancer. The development of new anticancer drugs or new uses for existing drugs is an exciting and increasing research area. This is particularly important since drug resistance and side effects can limit the efficacy of the chemotherapy. Thus, there is a need for multiplexed, cost-effective, rapid, and novel screening methods that can help to elucidate the mechanism of the action of anticancer drugs and the identification of novel drug candidates. This review focuses on different label-free bioelectrochemical approaches, in particular, impedance-based methods, the solid supported membranes technique, and the DNA-based electrochemical sensor, that can be used to evaluate the effects of anticancer drugs on nucleic acids, membrane transporters, and living cells. Some relevant examples of anticancer drug interactions are presented which demonstrate the usefulness of such methods for the characterization of the mechanism of action of anticancer drugs that are targeted against various biomolecules.
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Affiliation(s)
| | - Ilaria Palchetti
- Department of Chemistry "Ugo Schiff", University of Florence, 50019 Sesto Fiorentino, Italy
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13
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Abstract
Here, we present a protocol for the functional characterization of the H+-coupled human peptide transporter PepT1 and sufficient notes to transfer the protocol to the Na+-coupled sugar transporter SGLT1, the organic cation transporter OCT2, the Na+/Ca2+ exchanger NCX, and the neuronal glutamate transporter EAAT3.The assay was developed for the commercially available SURFE2R N1 instrument (Nanion Technologies GmbH) which applies solid supported membrane (SSM)-based electrophysiology. This technique is widely used for the functional characterization of membrane transporters with more than 100 different transporters characterized so far. The technique is cost-effective, easy to use, and capable of high-throughput measurements.SSM-based electrophysiology utilizes SSM-coated gold sensors to physically adsorb membrane vesicles containing the protein of interest. A fast solution exchange provides the substrate and activates transport. For the measurement of PepT1 activity, we applied a peptide concentration jump to activate H+/peptide symport. Proton influx charges the sensor. A capacitive current is measured reflecting the transport activity of PepT1 . Multiple measurements on the same sensor allow for comparison of transport activity under different conditions. Here, we determine EC50 for PepT1-mediated glycylglycine transport and perform an inhibition experiment using the specific peptide inhibitor Lys[Z(NO2)]-Val.
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14
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Zhang T, Sui D, Zhang C, Cole L, Hu J. Asymmetric functions of a binuclear metal center within the transport pathway of a human zinc transporter ZIP4. FASEB J 2019; 34:237-247. [PMID: 31914589 DOI: 10.1096/fj.201902043r] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 09/30/2019] [Accepted: 10/08/2019] [Indexed: 01/18/2023]
Abstract
Metal clusters are exploited by numerous metalloenzymes for catalysis, but it is not common to utilize a metal cluster for substrate transport across membrane. The recent crystal structure of a prototypic Zrt-/Irt-like protein (ZIP) metal transporter from Bordetella bronchiseptica (BbZIP) revealed an unprecedented binuclear metal center (BMC) within the transport pathway. Here, through a combination of bioinformatics, biochemical and structural approaches, we concluded that the two physically associated metal-binding sites in the BMC of human ZIP4 (hZIP4) zinc transporter exert different functions: one conserved transition metal-binding site acts as the transport site essential for activity, whereas the variable metal-binding site is required for hZIP4's optimal activity presumably by serving as a secondary transport site and modulating the properties of the primary transport site. Sequential soaking experiments on BbZIP crystals clarified the process of metal release from the BMC to the bulky solvent. This work provides important insights into the transport mechanism of the ZIPs broadly involved in transition metal homeostasis and signaling, and also a paradigm on a novel function of metal cluster in metalloproteins.
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Affiliation(s)
- Tuo Zhang
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Dexin Sui
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Chi Zhang
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Logan Cole
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Jian Hu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA.,Department of Chemistry, Michigan State University, East Lansing, MI, USA
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15
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Alwan KB, Welch EF, Blackburn NJ. Catalytic M Center of Copper Monooxygenases Probed by Rational Design. Effects of Selenomethionine and Histidine Substitution on Structure and Reactivity. Biochemistry 2019; 58:4436-4446. [PMID: 31626532 DOI: 10.1021/acs.biochem.9b00823] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The M centers of the mononuclear monooxygenases peptidylglycine monooxygenase (PHM) and dopamine β-monooxygenase bind and activate dioxygen en route to substrate hydroxylation. Recently, we reported the rational design of a protein-based model in which the CusF metallochaperone was repurposed via a His to Met mutation to act as a structural and spectroscopic biomimic. The PHM M site exhibits a number of unusual attributes, including a His2Met ligand set, a fluxional Cu(I)-S(Met) bond, tight binding of exogenous ligands CO and N3-, and complete coupling of oxygen reduction to substrate hydroxylation even at extremely low turnover rates. In particular, mutation of the Met ligand to His completely eliminates the catalytic activity despite the propensity of CuI-His3 centers to bind and activate dioxygen in other metalloenzyme systems. Here, we further develop the CusF-based model to explore methionine variants in which Met is replaced by selenomethionine (SeM) and histidine. We examine the effects on coordinate structure and exogenous ligand binding via X-ray absorption spectroscopy and electron paramagnetic resonance and probe the consequences of mutations on redox chemistry via studies of the reduction by ascorbate and oxidation via molecular oxygen. The M-site model is three-coordinate in the Cu(I) state and binds CO to form a four-coordinate carbonyl. In the oxidized forms, the coordination changes to tetragonal five-coordinate with a long axial Met ligand that like the enzymes is undetectable at either the Cu or Se K edges. The EXAFS data at the Se K edge of the SeM variant provide unique information about the nature of the Cu-methionine bond that is likewise weak and fluxional. Kinetic studies document the sluggish reactivity of the Cu(I) complexes with molecular oxygen and rapid rates of reduction of the Cu(II) complexes by ascorbate, indicating a remarkable stability of the Cu(I) state in all three derivatives. The results show little difference between the Met ligand and its SeM and His congeners and suggest that the Met contributes to catalysis in ways that are more complex than simple perturbation of the redox chemistry. Overall, the results stimulate a critical re-examination of the canonical reaction mechanisms of the mononuclear copper monooxygenases.
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Affiliation(s)
- Katherine B Alwan
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
| | - Evan F Welch
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
| | - Ninian J Blackburn
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
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16
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Petruzzelli R, Polishchuk RS. Activity and Trafficking of Copper-Transporting ATPases in Tumor Development and Defense against Platinum-Based Drugs. Cells 2019; 8:E1080. [PMID: 31540259 PMCID: PMC6769697 DOI: 10.3390/cells8091080] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/10/2019] [Accepted: 09/12/2019] [Indexed: 02/06/2023] Open
Abstract
Membrane trafficking pathways emanating from the Golgi regulate a wide range of cellular processes. One of these is the maintenance of copper (Cu) homeostasis operated by the Golgi-localized Cu-transporting ATPases ATP7A and ATP7B. At the Golgi, these proteins supply Cu to newly synthesized enzymes which use this metal as a cofactor to catalyze a number of vitally important biochemical reactions. However, in response to elevated Cu, the Golgi exports ATP7A/B to post-Golgi sites where they promote sequestration and efflux of excess Cu to limit its potential toxicity. Growing tumors actively consume Cu and employ ATP7A/B to regulate the availability of this metal for oncogenic enzymes such as LOX and LOX-like proteins, which confer higher invasiveness to malignant cells. Furthermore, ATP7A/B activity and trafficking allow tumor cells to detoxify platinum (Pt)-based drugs (like cisplatin), which are used for the chemotherapy of different solid tumors. Despite these noted activities of ATP7A/B that favor oncogenic processes, the mechanisms that regulate the expression and trafficking of Cu ATPases in malignant cells are far from being completely understood. This review summarizes current data on the role of ATP7A/B in the regulation of Cu and Pt metabolism in malignant cells and outlines questions and challenges that should be addressed to understand how ATP7A and ATP7B trafficking mechanisms might be targeted to counteract tumor development.
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Affiliation(s)
- Raffaella Petruzzelli
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy.
| | - Roman S Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy.
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17
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Alwan KB, Welch EF, Arias RJ, Gambill BF, Blackburn NJ. Rational Design of a Histidine-Methionine Site Modeling the M-Center of Copper Monooxygenases in a Small Metallochaperone Scaffold. Biochemistry 2019; 58:3097-3108. [PMID: 31243953 DOI: 10.1021/acs.biochem.9b00312] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mononuclear copper monooxygenases peptidylglycine monooxygenase (PHM) and dopamine β-monooxygenase (DBM) catalyze the hydroxylation of high energy C-H bonds utilizing a pair of chemically distinct copper sites (CuH and CuM) separated by 11 Å. In earlier work, we constructed single-site PHM variants that were designed to allow the study of the M- and H-centers independently in order to place their reactivity sequentially along the catalytic pathway. More recent crystallographic studies suggest that these single-site variants may not be truly representative of the individual active sites. In this work, we describe an alternative approach that uses a rational design to construct an artificial PHM model in a small metallochaperone scaffold. Using site-directed mutagenesis, we constructed variants that provide a His2Met copper-binding ligand set that mimics the M-center of PHM. The results show that the model accurately reproduces the chemical and spectroscopic properties of the M-center, including details of the methionine coordination, and the properties of Cu(I) and Cu(II) states in the presence of endogenous ligands such as CO and azide. The rate of reduction of the Cu(II) form of the model by the chromophoric reductant N,N'-dimethyl phenylenediamine (DMPD) has been compared with that of the PHM M-center, and the reaction chemistry of the Cu(I) forms with molecular oxygen has also been explored, revealing an unusually low reactivity toward molecular oxygen. This latter finding emphasizes the importance of substrate triggering of oxygen reactivity and implies that the His2Met ligand set, while necessary, is insufficient on its own to activate oxygen in these enzyme systems.
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Affiliation(s)
- Katherine B Alwan
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
| | - Evan F Welch
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
| | - Renee J Arias
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
| | - Ben F Gambill
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
| | - Ninian J Blackburn
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
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18
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X-Ray Absorption Spectroscopy of Metalloproteins. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2018; 1876:179-195. [PMID: 30317482 DOI: 10.1007/978-1-4939-8864-8_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
X-ray absorption spectroscopy (XAS) has been widely used as a powerful local structural tool for studying the metal binding sites in metalloproteins, owing to its element specificity, chemical sensitivity, and minimum requirement for sample preparation. The principle subject of this chapter is to provide a general introduction of this technique to molecular biologists and biochemists, with the intention to fill the knowledge gaps in interdisciplinary communication and collaboration. An update of the XAS-based technique applied recently to metalloproteins is also briefly introduced at the end of the chapter.
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19
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Abstract
Fungal cells colonize and proliferate in distinct niches, from soil and plants to diverse tissues in human hosts. Consequently, fungi are challenged with the goal of obtaining nutrients while simultaneously elaborating robust regulatory mechanisms to cope with a range of availability of nutrients, from scarcity to excess. Copper is essential for life but also potentially toxic. In this review we describe the sophisticated homeostatic mechanisms by which fungi acquire, utilize, and control this biochemically versatile trace element. Fungal pathogens, which can occupy distinct host tissues that have their own intrinsic requirements for copper homeostasis, have evolved mechanisms to acquire copper to successfully colonize the host, disseminate to other tissues, and combat host copper bombardment mechanisms that would otherwise mitigate virulence.
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Affiliation(s)
| | | | - Dennis J Thiele
- Department of Pharmacology and Cancer Biology.,Department of Molecular Genetics and Microbiology, and.,Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710;
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20
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Cu +-specific CopB transporter: Revising P 1B-type ATPase classification. Proc Natl Acad Sci U S A 2018; 115:2108-2113. [PMID: 29440418 DOI: 10.1073/pnas.1721783115] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The copper-transporting P1B-ATPases, which play a key role in cellular copper homeostasis, have been divided traditionally into two subfamilies, the P1B-1-ATPases or CopAs and the P1B-3-ATPases or CopBs. CopAs selectively export Cu+ whereas previous studies and bioinformatic analyses have suggested that CopBs are specific for Cu2+ export. Biochemical and spectroscopic characterization of Sphaerobacter thermophilus CopB (StCopB) show that, while it does bind Cu2+, the binding site is not the prototypical P1B-ATPase transmembrane site and does not involve sulfur coordination as proposed previously. Most important, StCopB exhibits metal-stimulated ATPase activity in response to Cu+, but not Cu2+, indicating that it is actually a Cu+ transporter. X-ray absorption spectroscopic studies indicate that Cu+ is coordinated by four sulfur ligands, likely derived from conserved cysteine and methionine residues. The histidine-rich N-terminal region of StCopB is required for maximal activity, but is inhibitory in the presence of divalent metal ions. Finally, reconsideration of the P1B-ATPase classification scheme suggests that the P1B-1- and P1B-3-ATPase subfamilies both comprise Cu+ transporters. These results are completely consistent with the known presence of only Cu+ within the reducing environment of the cytoplasm, which should eliminate the need for a Cu2+ P1B-ATPase.
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21
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Solioz M. Copper Homeostasis in Gram-Positive Bacteria. SPRINGERBRIEFS IN MOLECULAR SCIENCE 2018. [DOI: 10.1007/978-3-319-94439-5_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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22
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Abstract
Functional characterization of transport proteins using conventional electrophysiology can be challenging, especially for low turnover transporters or transporters from bacteria and intracellular compartments. Solid-supported membrane (SSM)-based electrophysiology is a sensitive and cell-free assay technique for the characterization of electrogenic membrane proteins. Purified proteins reconstituted into proteoliposomes or membrane vesicles from cell culture or native tissues are adsorbed to the sensor holding an SSM. A substrate or a ligand is applied via rapid solution exchange. The electrogenic transporter activity charges the sensor, which is recorded as a transient current. The high stability of the SSM allows cumulative measurements on the same sensor using different experimental conditions. This allows the determination of kinetic properties including EC50, IC50, Km, KD, and rate constants of electrogenic reactions. About 100 different transporters have been measured so far using this technique, among them symporters, exchangers, uniporters, ATP-, redox-, and light-driven ion pumps, as well as receptors and ion channels. Different instruments apply this technique: the laboratory setups use a closed flow-through arrangement, while the commercially available SURFE2R N1 resembles a pipetting robot. For drug screening purposes high-throughput systems, such as the SURFE2R 96SE enable the simultaneous measurement of up to 96 sensors.
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Affiliation(s)
- Andre Bazzone
- Max Planck Institute of Biophysics, Frankfurt/Main, Germany; Nanion Technologies GmbH, Munich, Germany
| | | | - Klaus Fendler
- Max Planck Institute of Biophysics, Frankfurt/Main, Germany.
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23
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Tadini-Buoninsegni F, Smeazzetto S. Mechanisms of charge transfer in human copper ATPases ATP7A and ATP7B. IUBMB Life 2017; 69:218-225. [PMID: 28164426 DOI: 10.1002/iub.1603] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 12/26/2016] [Indexed: 12/30/2022]
Abstract
ATP7A and ATP7B are Cu+ -transporting ATPases of subclass IB and play a fundamental role in intracellular copper homeostasis. ATP7A/B transfer Cu+ ions across the membrane from delivery to acceptor proteins without establishing a free Cu+ gradient. Transfer of copper across the membrane is coupled to ATP hydrolysis. Current measurements on solid supported membranes (SSM) were performed to investigate the mechanism of copper-related charge transfer across ATP7A and ATP7B. SSM measurements demonstrated that electrogenic copper displacement occurs within ATP7A/B following addition of ATP and formation of the phosphorylated intermediate. Comparison of the time constants for cation displacement in ATP7A/B and sarcoplasmic reticulum Ca2+ -ATPase is consistent with the slower phosphoenzyme formation in copper ATPases. Moreover, ATP-dependent copper transfer in ATP7A/B is not affected by varying the pH, suggesting that net proton counter-transport may not occur in copper ATPases. Platinum anticancer drugs activate ATP7A/B and are subjected to ATP-dependent vectorial displacement with a mechanism analogous to that of copper. © 2016 IUBMB Life, 69(4):218-225, 2017.
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Affiliation(s)
| | - Serena Smeazzetto
- Department of Chemistry "Ugo Schiff,", University of Florence, Sesto Fiorentino, Italy
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24
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Öhrvik H, Aaseth J, Horn N. Orchestration of dynamic copper navigation – new and missing pieces. Metallomics 2017; 9:1204-1229. [DOI: 10.1039/c7mt00010c] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A general principle in all cells in the body is that an essential metal – here copper – is taken up at the plasma membrane, directed through cellular compartments for use in specific enzymes and pathways, stored in specific scavenging molecules if in surplus, and finally expelled from the cells.
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Affiliation(s)
- Helena Öhrvik
- Medical Biochemistry and Microbiology
- Uppsala University
- Sweden
| | - Jan Aaseth
- Innlandet Hospital Trust and Inland Norway University of Applied Sciences
- Norway
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25
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Grønberg C, Sitsel O, Lindahl E, Gourdon P, Andersson M. Membrane Anchoring and Ion-Entry Dynamics in P-type ATPase Copper Transport. Biophys J 2016; 111:2417-2429. [PMID: 27926843 PMCID: PMC5153542 DOI: 10.1016/j.bpj.2016.10.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 09/29/2016] [Accepted: 10/17/2016] [Indexed: 12/23/2022] Open
Abstract
Cu+-specific P-type ATPase membrane protein transporters regulate cellular copper levels. The lack of crystal structures in Cu+-binding states has limited our understanding of how ion entry and binding are achieved. Here, we characterize the molecular basis of Cu+ entry using molecular-dynamics simulations, structural modeling, and in vitro and in vivo functional assays. Protein structural rearrangements resulting in the exposure of positive charges to bulk solvent rather than to lipid phosphates indicate a direct molecular role of the putative docking platform in Cu+ delivery. Mutational analyses and simulations in the presence and absence of Cu+ predict that the ion-entry path involves two ion-binding sites: one transient Met148-Cys382 site and one intramembranous site formed by trigonal coordination to Cys384, Asn689, and Met717. The results reconcile earlier biochemical and x-ray absorption data and provide a molecular understanding of ion entry in Cu+-transporting P-type ATPases.
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Affiliation(s)
| | | | - Erik Lindahl
- Biochemistry & Biophysics, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Pontus Gourdon
- University of Copenhagen, Copenhagen, Denmark; Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Magnus Andersson
- Theoretical Physics and Swedish e-Science Research Center, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden.
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26
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Sautron E, Giustini C, Dang T, Moyet L, Salvi D, Crouzy S, Rolland N, Catty P, Seigneurin-Berny D. Identification of Two Conserved Residues Involved in Copper Release from Chloroplast PIB-1-ATPases. J Biol Chem 2016; 291:20136-48. [PMID: 27493208 PMCID: PMC5025697 DOI: 10.1074/jbc.m115.706978] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/04/2016] [Indexed: 01/12/2023] Open
Abstract
Copper is an essential transition metal for living organisms. In the plant model Arabidopsis thaliana, half of the copper content is localized in the chloroplast, and as a cofactor of plastocyanin, copper is essential for photosynthesis. Within the chloroplast, copper delivery to plastocyanin involves two transporters of the PIB-1-ATPases subfamily: HMA6 at the chloroplast envelope and HMA8 in the thylakoid membranes. Both proteins are high affinity copper transporters but share distinct enzymatic properties. In the present work, the comparison of 140 sequences of PIB-1-ATPases revealed a conserved region unusually rich in histidine and cysteine residues in the TMA-L1 region of eukaryotic chloroplast copper ATPases. To evaluate the role of these residues, we mutated them in HMA6 and HMA8. Mutants of interest were selected from phenotypic tests in yeast and produced in Lactococcus lactis for further biochemical characterizations using phosphorylation assays from ATP and Pi Combining functional and structural data, we highlight the importance of the cysteine and the first histidine of the CX3HX2H motif in the process of copper release from HMA6 and HMA8 and propose a copper pathway through the membrane domain of these transporters. Finally, our work suggests a more general role of the histidine residue in the transport of copper by PIB-1-ATPases.
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Affiliation(s)
- Emeline Sautron
- From the CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, F-38054 Grenoble, France, the Université Grenoble Alpes, F-38054 Grenoble, France, the CEA, DSV, BIG, F-38054 Grenoble, France, the INRA, LPCV, UMR 1417, F-38054 Grenoble, France, and
| | - Cécile Giustini
- From the CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, F-38054 Grenoble, France, the Université Grenoble Alpes, F-38054 Grenoble, France, the CEA, DSV, BIG, F-38054 Grenoble, France, the INRA, LPCV, UMR 1417, F-38054 Grenoble, France, and
| | - ThuyVan Dang
- From the CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, F-38054 Grenoble, France, the Université Grenoble Alpes, F-38054 Grenoble, France, the CEA, DSV, BIG, F-38054 Grenoble, France, the INRA, LPCV, UMR 1417, F-38054 Grenoble, France, and
| | - Lucas Moyet
- From the CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, F-38054 Grenoble, France, the Université Grenoble Alpes, F-38054 Grenoble, France, the CEA, DSV, BIG, F-38054 Grenoble, France, the INRA, LPCV, UMR 1417, F-38054 Grenoble, France, and
| | - Daniel Salvi
- From the CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, F-38054 Grenoble, France, the Université Grenoble Alpes, F-38054 Grenoble, France, the CEA, DSV, BIG, F-38054 Grenoble, France, the INRA, LPCV, UMR 1417, F-38054 Grenoble, France, and
| | - Serge Crouzy
- the Université Grenoble Alpes, F-38054 Grenoble, France, the CEA, DSV, BIG, F-38054 Grenoble, France, the CNRS, Laboratoire de Chimie et Biologie des Métaux, UMR 5249, F-38054 Grenoble, France
| | - Norbert Rolland
- From the CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, F-38054 Grenoble, France, the Université Grenoble Alpes, F-38054 Grenoble, France, the CEA, DSV, BIG, F-38054 Grenoble, France, the INRA, LPCV, UMR 1417, F-38054 Grenoble, France, and
| | - Patrice Catty
- the Université Grenoble Alpes, F-38054 Grenoble, France, the CEA, DSV, BIG, F-38054 Grenoble, France, the CNRS, Laboratoire de Chimie et Biologie des Métaux, UMR 5249, F-38054 Grenoble, France
| | - Daphné Seigneurin-Berny
- From the CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, F-38054 Grenoble, France, the Université Grenoble Alpes, F-38054 Grenoble, France, the CEA, DSV, BIG, F-38054 Grenoble, France, the INRA, LPCV, UMR 1417, F-38054 Grenoble, France, and
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27
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Argüello JM, Patel SJ, Quintana J. Bacterial Cu(+)-ATPases: models for molecular structure-function studies. Metallomics 2016; 8:906-14. [PMID: 27465346 PMCID: PMC5025381 DOI: 10.1039/c6mt00089d] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The early discovery of the human Cu(+)-ATPases and their link to Menkes and Wilson's diseases brought attention to the unique role of these transporters in copper homeostasis. The characterization of bacterial Cu(+)-ATPases has significantly furthered our understanding of the structure, selectivity and transport mechanism of these enzymes, as well as their interplay with other elements of Cu(+) distribution networks. This review focuses on the structural-functional insights that have emerged from studies of bacterial Cu(+)-ATPases at the molecular level and how these observations have contributed to drawing up a comprehensive picture of cellular copper homeostasis.
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Affiliation(s)
- José M Argüello
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA.
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28
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Capdevila DA, Wang J, Giedroc DP. Bacterial Strategies to Maintain Zinc Metallostasis at the Host-Pathogen Interface. J Biol Chem 2016; 291:20858-20868. [PMID: 27462080 DOI: 10.1074/jbc.r116.742023] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Among the biologically required first row, late d-block metals from MnII to ZnII, the catalytic and structural reach of ZnII ensures that this essential micronutrient touches nearly every major metabolic process or pathway in the cell. Zn is also toxic in excess, primarily because it is a highly competitive divalent metal and will displace more weakly bound transition metals in the active sites of metalloenzymes if left unregulated. The vertebrate innate immune system uses several strategies to exploit this "Achilles heel" of microbial physiology, but bacterial evolution has responded in kind. This review highlights recent insights into transcriptional, transport, and trafficking mechanisms that pathogens use to "win the fight" over zinc and thrive in an otherwise hostile environment.
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Affiliation(s)
- Daiana A Capdevila
- From the Departments of Chemistry and the Departamento de Quimica Inorganica, Analitica y Quimica Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EHA, Argentina
| | - Jiefei Wang
- From the Departments of Chemistry and Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405-7102 and
| | - David P Giedroc
- From the Departments of Chemistry and Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405-7102 and
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29
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Oppermann A, Dick R, Wehrhahn C, Flörke U, Herres-Pawlis S, Henkel G. Copper(I) Thiolate Heteroadamantane Cage Structures with Relevance to Metalloproteins. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201600247] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Alexander Oppermann
- Fachgruppe Chemie; RWTH Aachen University; Institut für Anorganische Chemie; Landoltweg 1 52074 Aachen Germany
| | - Regina Dick
- Department of Chemistry; Universität Paderborn; Warburger Str. 100 33098 Paderborn Germany
| | - Christoph Wehrhahn
- Department of Chemistry; Universität Paderborn; Warburger Str. 100 33098 Paderborn Germany
| | - Ulrich Flörke
- Department of Chemistry; Universität Paderborn; Warburger Str. 100 33098 Paderborn Germany
| | - Sonja Herres-Pawlis
- Fachgruppe Chemie; RWTH Aachen University; Institut für Anorganische Chemie; Landoltweg 1 52074 Aachen Germany
| | - Gerald Henkel
- Department of Chemistry; Universität Paderborn; Warburger Str. 100 33098 Paderborn Germany
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30
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Fu Y, Bruce KE, Wu H, Giedroc DP. The S2 Cu(i) site in CupA from Streptococcus pneumoniae is required for cellular copper resistance. Metallomics 2016; 8:61-70. [PMID: 26346139 PMCID: PMC4720546 DOI: 10.1039/c5mt00221d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Pathogenic bacteria have evolved copper homeostasis and resistance systems for fighting copper toxicity imposed by the human immune system. Streptococcus pneumoniae is a respiratory pathogen that encodes an obligatorily membrane-anchored Cu(i) binding protein, CupA, and a P1B-type ATPase efflux transporter, CopA. The soluble, cytoplasmic domain of CupA (sCupA) contains a binuclear Cu(i) cluster consisting of S1 and S2 Cu(i) ions. The NMR solution structure of apo-sCupA reveals the same cupredoxin fold of Cu2-sCupA, except that the Cu(i) binding loop (residues 112-116, harboring S2 Cu ligands M113 and M115) is highly dynamic as documented by both backbone and side chain methionine methyl order parameters. In contrast to the more solvent exposed, lower affinity S2 Cu site, the high affinity S1 Cu-coordinating cysteines (C74, C111) are pre-organized in the apo-sCupA structure. Biological experiments reveal that the S1 site is largely dispensable for cellular Cu resistance and may be involved in buffering low cytoplasmic Cu(i). In contrast, the S2 site is essential for Cu resistance. Expression of a chimeric CopZ chaperone fused to the CupA transmembrane helix does not protect S. pneumoniae from copper toxicity and substitution of a predicted cytoplasm-facing Cu(i) entry metal-binding site (MBS) on CopA also gives rise to a Cu-sensitivity phenotype. These findings suggest that CupA and CopA may interact and filling of the CupA S2 site with Cu(i) results in stimulation of cellular copper efflux by CopA.
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Affiliation(s)
- Yue Fu
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, USA. and Graduate Program in Biochemistry, Indiana University, Bloomington, Indiana 47405-7102, USA
| | - Kevin E Bruce
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
| | - Hongwei Wu
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, USA.
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, USA.
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31
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Sitsel O, Grønberg C, Autzen HE, Wang K, Meloni G, Nissen P, Gourdon P. Structure and Function of Cu(I)- and Zn(II)-ATPases. Biochemistry 2015; 54:5673-83. [PMID: 26132333 DOI: 10.1021/acs.biochem.5b00512] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Copper and zinc are micronutrients essential for the function of many enzymes while also being toxic at elevated concentrations. Cu(I)- and Zn(II)-transporting P-type ATPases of subclass 1B are of key importance for the homeostasis of these transition metals, allowing ion transport across cellular membranes at the expense of ATP. Recent biochemical studies and crystal structures have significantly improved our understanding of the transport mechanisms of these proteins, but many details about their structure and function remain elusive. Here we compare the Cu(I)- and Zn(II)-ATPases, scrutinizing the molecular differences that allow transport of these two distinct metal types, and discuss possible future directions of research in the field.
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Affiliation(s)
- Oleg Sitsel
- Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation, Department of Molecular Biology and Genetics, Aarhus University , Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark
| | - Christina Grønberg
- Department of Biomedical Sciences, University of Copenhagen , Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
| | - Henriette Elisabeth Autzen
- Department of Biomedical Sciences, University of Copenhagen , Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
| | - Kaituo Wang
- Department of Biomedical Sciences, University of Copenhagen , Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
| | - Gabriele Meloni
- Division of Chemistry and Chemical Engineering and Howard Hughes Medical Institute, California Institute of Technology , Pasadena, California 91125, United States
| | - Poul Nissen
- Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation, Department of Molecular Biology and Genetics, Aarhus University , Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark
| | - Pontus Gourdon
- Department of Biomedical Sciences, University of Copenhagen , Blegdamsvej 3B, DK-2200 Copenhagen, Denmark.,Department of Experimental Medical Science, Lund University , Sölvegatan 19, SE-221 84 Lund, Sweden
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