1
|
Fortino M, Arnesano F, Pietropaolo A. Unraveling Copper Exchange in the Atox1-Cu(I)-Mnk1 Heterodimer: A Simulation Approach. J Phys Chem B 2024; 128:5336-5343. [PMID: 38780400 DOI: 10.1021/acs.jpcb.4c01026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
Copper, an essential metal for various cellular processes, requires tight regulation to prevent cytotoxicity. Intracellular pathways crucial for maintaining optimal copper levels involve soluble and membrane transporters, namely, metallochaperones and P-type ATPases, respectively. In this study, we used a simulation workflow based on free-energy perturbation (FEP) theory and parallel bias metadynamics (PBMetaD) to predict the Cu(I) exchange mechanism between the human Cu(I) chaperone, Atox1, and one of its two physiological partners, ATP7A. ATP7A, also known as the Menkes disease protein, is a transmembrane protein and one of the main copper-transporting ATPases. It pumps copper into the trans-Golgi network for the maturation of cuproenzymes and is also essential for the efflux of excess copper across the plasma membrane. In this analysis, we utilized the nuclear magnetic resonance (NMR) structure of the Cu(I)-mediated complex between Atox1 and the first soluble domain of the Menkes protein (Mnk1) as a starting point. Independent free-energy simulations were conducted to investigate the dissociation of both Atox1 and Mnk1. The calculations revealed that the two dissociations require free energy values of 6.3 and 6.2 kcal/mol, respectively, following a stepwise dissociation mechanism.
Collapse
Affiliation(s)
- Mariagrazia Fortino
- Dipartimento di Scienze della Salute, Università Magna Graecia di Catanzaro, Viale Europa, 88100 Catanzaro, Italy
| | - Fabio Arnesano
- Dipartimento di Chimica, Università di Bari "Aldo Moro", Via Orabona 4, 70125 Bari, Italy
| | - Adriana Pietropaolo
- Dipartimento di Scienze della Salute, Università Magna Graecia di Catanzaro, Viale Europa, 88100 Catanzaro, Italy
| |
Collapse
|
2
|
Igbaria-Jaber Y, Hofmann L, Gevorkyan-Airapetov L, Shenberger Y, Ruthstein S. Revealing the DNA Binding Modes of CsoR by EPR Spectroscopy. ACS OMEGA 2023; 8:39886-39895. [PMID: 37901548 PMCID: PMC10601412 DOI: 10.1021/acsomega.3c06336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 09/28/2023] [Indexed: 10/31/2023]
Abstract
In pathogens, a unique class of metalloregulator proteins, called gene regulatory proteins, sense specific metal ions that initiate gene transcription of proteins that export metal ions from the cell, thereby preventing toxicity and cell death. CsoR is a metalloregulator protein found in various bacterial systems that "sense" Cu(I) ions with high affinity. Upon copper binding, CsoR dissociates from the DNA promoter region, resulting in initiation of gene transcription. Crystal structures of CsoR in the presence and absence of Cu(I) from various bacterial systems have been reported, suggesting either a dimeric or tetrameric structure of these helical proteins. However, structural information about the CsoR-DNA complex is missing. Here, we applied electron paramagnetic resonance (EPR) spectroscopy to follow the conformational and dynamical changes that Mycobacterium tuberculosis CsoR undergoes upon DNA binding in solution. We showed that the quaternary structure is predominantly dimeric in solution, and only minor conformational and dynamical changes occur in the DNA bound state. Also, labeling of the unresolved C- terminus revealed no significant change in dynamics upon DNA binding. These observations are unique, since for other bacterial copper metalloregulators, such as the MerR and CopY families, major conformational changes were observed upon DNA binding, indicating a different mode of action for this protein family.
Collapse
Affiliation(s)
- Yasmin Igbaria-Jaber
- Department of Chemistry and the Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Lukas Hofmann
- Department of Chemistry and the Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Lada Gevorkyan-Airapetov
- Department of Chemistry and the Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Yulia Shenberger
- Department of Chemistry and the Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Sharon Ruthstein
- Department of Chemistry and the Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 52900, Israel
| |
Collapse
|
3
|
Qasem Z, Pavlin M, Ritacco I, Avivi MY, Meron S, Hirsch M, Shenberger Y, Gevorkyan-Airapetov L, Magistrato A, Ruthstein S. Disrupting Cu trafficking as a potential therapy for cancer. Front Mol Biosci 2022; 9:1011294. [PMID: 36299299 PMCID: PMC9589254 DOI: 10.3389/fmolb.2022.1011294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 09/26/2022] [Indexed: 11/13/2022] Open
Abstract
Copper ions play a crucial role in various cellular biological processes. However, these copper ions can also lead to toxicity when their concentration is not controlled by a sophisticated copper-trafficking system. Copper dys-homeostasis has been linked to a variety of diseases, including neurodegeneration and cancer. Therefore, manipulating Cu-trafficking to trigger selective cancer cell death may be a viable strategy with therapeutic benefit. By exploiting combined in silico and experimental strategies, we identified small peptides able to bind Atox1 and metal-binding domains 3-4 of ATP7B proteins. We found that these peptides reduced the proliferation of cancer cells owing to increased cellular copper ions concentration. These outcomes support the idea of harming copper trafficking as an opportunity for devising novel anti-cancer therapies.
Collapse
Affiliation(s)
- Zena Qasem
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan, Israel
| | - Matic Pavlin
- National Research Council of Italy (CNR)—Institute of Material (IOM) C/o International School for Advanced Studies (SISSA), Trieste, Italy
- Department of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Ljubljana, Slovenia
| | - Ida Ritacco
- National Research Council of Italy (CNR)—Institute of Material (IOM) C/o International School for Advanced Studies (SISSA), Trieste, Italy
- Department of Chemistry, University of Salerno, Salerno, Italy
| | - Matan Y. Avivi
- The Mina and Everard Goodman Faculty of Life-Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Shelly Meron
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan, Israel
| | - Melanie Hirsch
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan, Israel
| | - Yulia Shenberger
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan, Israel
| | - Lada Gevorkyan-Airapetov
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan, Israel
| | - Alessandra Magistrato
- National Research Council of Italy (CNR)—Institute of Material (IOM) C/o International School for Advanced Studies (SISSA), Trieste, Italy
- *Correspondence: Alessandra Magistrato, ; Sharon Ruthstein,
| | - Sharon Ruthstein
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan, Israel
- *Correspondence: Alessandra Magistrato, ; Sharon Ruthstein,
| |
Collapse
|
4
|
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.
Collapse
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
| | | |
Collapse
|
5
|
Janoš P, Aupič J, Ruthstein S, Magistrato A. The conformational plasticity of the selectivity filter methionines controls the in-cell Cu(I) uptake through the CTR1 transporter. QRB DISCOVERY 2022; 3:e3. [PMID: 37529280 PMCID: PMC10392627 DOI: 10.1017/qrd.2022.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 03/25/2022] [Accepted: 04/01/2022] [Indexed: 11/05/2022] Open
Abstract
Copper is a trace element vital to many cellular functions. Yet its abnormal levels are toxic to cells, provoking a variety of severe diseases. The high affinity copper transporter 1 (CTR1), being the main in-cell copper [Cu(I)] entry route, tightly regulates its cellular uptake via a still elusive mechanism. Here, all-atoms simulations unlock the molecular terms of Cu(I) transport in eukaryotes disclosing that the two methionine (Met) triads, forming the selectivity filter, play an unprecedented dual role both enabling selective Cu(I) transport and regulating its uptake rate thanks to an intimate coupling between the conformational plasticity of their bulky side chains and the number of bound Cu(I) ions. Namely, the Met residues act as a gate reducing the Cu(I) import rate when two ions simultaneously bind to CTR1. This may represent an elegant autoregulatory mechanism through which CTR1 protects the cells from excessively high, and hence toxic, in-cell Cu(I) levels. Overall, our outcomes resolve fundamental questions in CTR1 biology and open new windows of opportunity to tackle diseases associated with an imbalanced copper uptake.
Collapse
Affiliation(s)
- Pavel Janoš
- Consiglio Nazionale delle ricerche/National Research Council (CNR) -IOM c/o International School for Advanced Studies (SISSA/ISAS), via Bonomea 265, 34136Trieste, Italy
| | - Jana Aupič
- Consiglio Nazionale delle ricerche/National Research Council (CNR) -IOM c/o International School for Advanced Studies (SISSA/ISAS), via Bonomea 265, 34136Trieste, Italy
| | - Sharon Ruthstein
- Department of Chemistry, Faculty of Exact Sciences and the Institute for Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, 5290002Ramat-Gan, Israel
| | - Alessandra Magistrato
- Consiglio Nazionale delle ricerche/National Research Council (CNR) -IOM c/o International School for Advanced Studies (SISSA/ISAS), via Bonomea 265, 34136Trieste, Italy
| |
Collapse
|
6
|
The Advantages of EPR Spectroscopy in Exploring Diamagnetic Metal Ion Binding and Transfer Mechanisms in Biological Systems. MAGNETOCHEMISTRY 2021. [DOI: 10.3390/magnetochemistry8010003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Electron paramagnetic resonance (EPR) spectroscopy has emerged as an ideal biophysical tool to study complex biological processes. EPR spectroscopy can follow minor conformational changes in various proteins as a function of ligand or protein binding or interactions with high resolution and sensitivity. Resolving cellular mechanisms, involving small ligand binding or metal ion transfer, is not trivial and cannot be studied using conventional biophysical tools. In recent years, our group has been using EPR spectroscopy to study the mechanism underlying copper ion transfer in eukaryotic and prokaryotic systems. This mini-review focuses on our achievements following copper metal coordination in the diamagnetic oxidation state, Cu(I), between biomolecules. We discuss the conformational changes induced in proteins upon Cu(I) binding, as well as the conformational changes induced in two proteins involved in Cu(I) transfer. We also consider how EPR spectroscopy, together with other biophysical and computational tools, can identify the Cu(I)-binding sites. This work describes the advantages of EPR spectroscopy for studying biological processes that involve small ligand binding and transfer between intracellular proteins.
Collapse
|
7
|
Beyond Single-Cell Analysis of Metallodrugs by ICP-MS: Targeting Cellular Substructures. Int J Mol Sci 2021; 22:ijms22179468. [PMID: 34502377 PMCID: PMC8431512 DOI: 10.3390/ijms22179468] [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: 08/02/2021] [Revised: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 12/25/2022] Open
Abstract
Platinum compounds such as cisplatin (cisPt) embody the backbone of combination chemotherapy protocols against advanced lung cancer. However, their efficacy is primarily limited by inherent or acquired platinum resistance, the origin of which has not been fully elucidated yet, although of paramount interest. Using single cell inductively coupled plasma mass spectrometry (SC-ICP-MS), this study quantifies cisPt in single cancer cells and for the first time in isolated nuclei. A comparison of cisPt uptake was performed between a wild type (wt) cancer cell line and related resistant sublines. In both, resistant cells, wt cells, and their nuclei, cisPt uptake was measured at different incubation times. A lower amount of cisPt was found in resistant cell lines and their nuclei compared to wt cells. Moreover, the abundance of internalized cisPt decreased with increasing resistance. Interestingly, concentrations of cisPt found within the nuclei were higher than compared to cellular concentrations. Here, we show, that SC-ICP-MS allows precise and accurate quantification of metallodrugs in both single cells and cell organelles such as nuclei. These findings pave the way for future applications investigating the potency and efficacy of novel metallodrugs developed for cancer treatment.
Collapse
|
8
|
Spinello A, Borišek J, Pavlin M, Janoš P, Magistrato A. Computing Metal-Binding Proteins for Therapeutic Benefit. ChemMedChem 2021; 16:2034-2049. [PMID: 33740297 DOI: 10.1002/cmdc.202100109] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Indexed: 01/18/2023]
Abstract
Over one third of biomolecules rely on metal ions to exert their cellular functions. Metal ions can play a structural role by stabilizing the structure of biomolecules, a functional role by promoting a wide variety of biochemical reactions, and a regulatory role by acting as messengers upon binding to proteins regulating cellular metal-homeostasis. These diverse roles in biology ascribe critical implications to metal-binding proteins in the onset of many diseases. Hence, it is of utmost importance to exhaustively unlock the different mechanistic facets of metal-binding proteins and to harness this knowledge to rationally devise novel therapeutic strategies to prevent or cure pathological states associated with metal-dependent cellular dysfunctions. In this compendium, we illustrate how the use of a computational arsenal based on docking, classical, and quantum-classical molecular dynamics simulations can contribute to extricate the minutiae of the catalytic, transport, and inhibition mechanisms of metal-binding proteins at the atomic level. This knowledge represents a fertile ground and an essential prerequisite for selectively targeting metal-binding proteins with small-molecule inhibitors aiming to (i) abrogate deregulated metal-dependent (mis)functions or (ii) leverage metal-dyshomeostasis to selectively trigger harmful cells death.
Collapse
Affiliation(s)
- Angelo Spinello
- National Research Council of Italy (CNR)-, Institute of Materials (IOM) c/o International School for Advanced Studies (SISSA), via Bonomea 265, 34136, Trieste, Italy
| | - Jure Borišek
- National Institute of Chemistry Institution Hajdrihova ulica 19, 1000, Ljubljana, Slovenia
| | - Matic Pavlin
- Laboratory of Microsensor Structures and Electronics Faculty of Electrical Engineering, University of Ljubljana Tržaška cesta 25, 1000, Ljubljana, Slovenia
| | - Pavel Janoš
- National Research Council of Italy (CNR)-, Institute of Materials (IOM) c/o International School for Advanced Studies (SISSA), via Bonomea 265, 34136, Trieste, Italy
| | - Alessandra Magistrato
- National Research Council of Italy (CNR)-, Institute of Materials (IOM) c/o International School for Advanced Studies (SISSA), via Bonomea 265, 34136, Trieste, Italy
| |
Collapse
|
9
|
Palermo G, Spinello A, Saha A, Magistrato A. Frontiers of metal-coordinating drug design. Expert Opin Drug Discov 2020; 16:497-511. [PMID: 33874825 DOI: 10.1080/17460441.2021.1851188] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Introduction: The occurrence of metal ions in biomolecules is required to exert vital cellular functions. Metal-containing biomolecules can be modulated by small-molecule inhibitors targeting their metal-moiety. As well, the discovery of cisplatin ushered the rational discovery of metal-containing-drugs. The use of both drug types exploiting metal-ligand interactions is well established to treat distinct pathologies. Therefore, characterizing and leveraging metal-coordinating drugs is a pivotal, yet challenging, part of medicinal chemistry.Area covered: Atomic-level simulations are increasingly employed to overcome the challenges met by traditional drug-discovery approaches and to complement wet-lab experiments in elucidating the mechanisms of drugs' action. Multiscale simulations, allow deciphering the mechanism of metal-binding inhibitors and metallo-containing-drugs, enabling a reliable description of metal-complexes in their biological environment. In this compendium, the authors review selected applications exploiting the metal-ligand interactions by focusing on understanding the mechanism and design of (i) inhibitors targeting iron and zinc-enzymes, and (ii) ruthenium and gold-based anticancer agents targeting the nucleosome and aquaporin protein, respectively.Expert opinion: The showcased applications exemplify the current role and the potential of atomic-level simulations and reveal how their synergic use with experiments can contribute to uncover fundamental mechanistic facets and exploit metal-ligand interactions in medicinal chemistry.
Collapse
Affiliation(s)
- Giulia Palermo
- Department of Bioengineering and Department of Chemistry, University of California Riverside, Riverside, United States
| | - Angelo Spinello
- National Research Council (CNR) of Italy, Institute of Material (IOM) @ International School for Advanced Studies (SISSA), Trieste, Italy
| | - Aakash Saha
- Department of Bioengineering, University of California Riverside, Riverside, United States
| | - Alessandra Magistrato
- National Research Council (CNR) of Italy, Institute of Material (IOM) @ International School for Advanced Studies (SISSA), Trieste, Italy
| |
Collapse
|
10
|
Zaccak M, Qasem Z, Gevorkyan-Airapetov L, Ruthstein S. An EPR Study on the Interaction between the Cu(I) Metal Binding Domains of ATP7B and the Atox1 Metallochaperone. Int J Mol Sci 2020; 21:ijms21155536. [PMID: 32748830 PMCID: PMC7432781 DOI: 10.3390/ijms21155536] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 07/29/2020] [Accepted: 07/30/2020] [Indexed: 02/07/2023] Open
Abstract
Copper’s essentiality and toxicity mean it requires a sophisticated regulation system for its acquisition, cellular distribution and excretion, which until now has remained elusive. Herein, we applied continuous wave (CW) and pulsed electron paramagnetic resonance (EPR) spectroscopy in solution to resolve the copper trafficking mechanism in humans, by considering the route travelled by Cu(I) from the metallochaperone Atox1 to the metal binding domains of ATP7B. Our study revealed that Cu(I) is most likely mediated by the binding of the Atox1 monomer to metal binding domain 1 (MBD1) and MBD4 of ATP7B in the final part of its extraction pathway, while the other MBDs mediate this interaction and participate in copper transfer between the various MBDs to the ATP7B membrane domain. This research also proposes that MBD1-3 and MBD4-6 act as two independent units.
Collapse
|
11
|
Perkal O, Qasem Z, Turgeman M, Schwartz R, Gevorkyan-Airapetov L, Pavlin M, Magistrato A, Major DT, Ruthstein S. Cu(I) Controls Conformational States in Human Atox1 Metallochaperone: An EPR and Multiscale Simulation Study. J Phys Chem B 2020; 124:4399-4411. [PMID: 32396355 PMCID: PMC7294806 DOI: 10.1021/acs.jpcb.0c01744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
![]()
Atox1 is a human
copper metallochaperone that is responsible for
transferring copper ions from the main human copper transporter, hCtr1,
to ATP7A/B in the Golgi apparatus. Atox1 interacts with the Ctr1 C-terminal
domain as a dimer, although it transfers the copper ions to ATP7A/B
in a monomeric form. The copper binding site in the Atox1 dimer involves
Cys12 and Cys15, while Lys60 was also suggested to play a role in
the copper binding. We recently showed that Atox1 can adopt various
conformational states, depending on the interacting protein. In the
current study, we apply EPR experiments together with hybrid quantum
mechanics–molecular mechanics molecular dynamics simulations
using a recently developed semiempirical density functional theory
approach, to better understand the effect of Atox1’s conformational
states on copper coordination. We propose that the flexibility of
Atox1 occurs owing to protonation of one or more of the cysteine residues,
and that Cys15 is an important residue for Atox1 dimerization, while
Cys12 is a critical residue for Cu(I) binding. We also show that Lys60
electrostatically stabilizes the Cu(I)–Atox1 dimer.
Collapse
Affiliation(s)
- Ortal Perkal
- Department of Chemistry and Institute for Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Zena Qasem
- Department of Chemistry, Faculty of Exact Sciences, Bar Ilan University, Ramat-Gan 5290002, Israel
| | - Meital Turgeman
- Department of Chemistry, Faculty of Exact Sciences, Bar Ilan University, Ramat-Gan 5290002, Israel
| | - Renana Schwartz
- Department of Chemistry and Institute for Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Lada Gevorkyan-Airapetov
- Department of Chemistry, Faculty of Exact Sciences, Bar Ilan University, Ramat-Gan 5290002, Israel
| | - Matic Pavlin
- CNR-IOM at SISSA, via Bonomea 265, 34135, Trieste, Italy
| | | | - Dan Thomas Major
- Department of Chemistry and Institute for Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Sharon Ruthstein
- Department of Chemistry, Faculty of Exact Sciences, Bar Ilan University, Ramat-Gan 5290002, Israel
| |
Collapse
|
12
|
Pavlin M, Qasem Z, Sameach H, Gevorkyan-Airapetov L, Ritacco I, Ruthstein S, Magistrato A. Unraveling the Impact of Cysteine-to-Serine Mutations on the Structural and Functional Properties of Cu(I)-Binding Proteins. Int J Mol Sci 2019; 20:E3462. [PMID: 31337158 PMCID: PMC6679193 DOI: 10.3390/ijms20143462] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 07/09/2019] [Accepted: 07/11/2019] [Indexed: 02/03/2023] Open
Abstract
Appropriate maintenance of Cu(I) homeostasis is an essential requirement for proper cell function because its misregulation induces the onset of major human diseases and mortality. For this reason, several research efforts have been devoted to dissecting the inner working mechanism of Cu(I)-binding proteins and transporters. A commonly adopted strategy relies on mutations of cysteine residues, for which Cu(I) has an exquisite complementarity, to serines. Nevertheless, in spite of the similarity between these two amino acids, the structural and functional impact of serine mutations on Cu(I)-binding biomolecules remains unclear. Here, we applied various biochemical and biophysical methods, together with all-atom simulations, to investigate the effect of these mutations on the stability, structure, and aggregation propensity of Cu(I)-binding proteins, as well as their interaction with specific partner proteins. Among Cu(I)-binding biomolecules, we focused on the eukaryotic Atox1-ATP7B system, and the prokaryotic CueR metalloregulator. Our results reveal that proteins containing cysteine-to-serine mutations can still bind Cu(I) ions; however, this alters their stability and aggregation propensity. These results contribute to deciphering the critical biological principles underlying the regulatory mechanism of the in-cell Cu(I) concentration, and provide a basis for interpreting future studies that will take advantage of cysteine-to-serine mutations in Cu(I)-binding systems.
Collapse
Affiliation(s)
- Matic Pavlin
- CNR-IOM at SISSA, via Bonomea 265, 34135 Trieste, Italy
| | - Zena Qasem
- Department of Chemistry, Faculty of Exact Sciences, Bar Ilan University, Ramat-Gan 5290002, Israel
| | - Hila Sameach
- Department of Chemistry, Faculty of Exact Sciences, Bar Ilan University, Ramat-Gan 5290002, Israel
| | - Lada Gevorkyan-Airapetov
- Department of Chemistry, Faculty of Exact Sciences, Bar Ilan University, Ramat-Gan 5290002, Israel
| | - Ida Ritacco
- CNR-IOM at SISSA, via Bonomea 265, 34135 Trieste, Italy
| | - Sharon Ruthstein
- Department of Chemistry, Faculty of Exact Sciences, Bar Ilan University, Ramat-Gan 5290002, Israel.
| | | |
Collapse
|