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Badiee SA, Isu UH, Khodadadi E, Moradi M. The Alternating Access Mechanism in Mammalian Multidrug Resistance Transporters and Their Bacterial Homologs. MEMBRANES 2023; 13:568. [PMID: 37367772 DOI: 10.3390/membranes13060568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 05/23/2023] [Accepted: 05/27/2023] [Indexed: 06/28/2023]
Abstract
Multidrug resistance (MDR) proteins belonging to the ATP-Binding Cassette (ABC) transporter group play a crucial role in the export of cytotoxic drugs across cell membranes. These proteins are particularly fascinating due to their ability to confer drug resistance, which subsequently leads to the failure of therapeutic interventions and hinders successful treatments. One key mechanism by which multidrug resistance (MDR) proteins carry out their transport function is through alternating access. This mechanism involves intricate conformational changes that enable the binding and transport of substrates across cellular membranes. In this extensive review, we provide an overview of ABC transporters, including their classifications and structural similarities. We focus specifically on well-known mammalian multidrug resistance proteins such as MRP1 and Pgp (MDR1), as well as bacterial counterparts such as Sav1866 and lipid flippase MsbA. By exploring the structural and functional features of these MDR proteins, we shed light on the roles of their nucleotide-binding domains (NBDs) and transmembrane domains (TMDs) in the transport process. Notably, while the structures of NBDs in prokaryotic ABC proteins, such as Sav1866, MsbA, and mammalian Pgp, are identical, MRP1 exhibits distinct characteristics in its NBDs. Our review also emphasizes the importance of two ATP molecules for the formation of an interface between the two binding sites of NBD domains across all these transporters. ATP hydrolysis occurs following substrate transport and is vital for recycling the transporters in subsequent cycles of substrate transportation. Specifically, among the studied transporters, only NBD2 in MRP1 possesses the ability to hydrolyze ATP, while both NBDs of Pgp, Sav1866, and MsbA are capable of carrying out this reaction. Furthermore, we highlight recent advancements in the study of MDR proteins and the alternating access mechanism. We discuss the experimental and computational approaches utilized to investigate the structure and dynamics of MDR proteins, providing valuable insights into their conformational changes and substrate transport. This review not only contributes to an enhanced understanding of multidrug resistance proteins but also holds immense potential for guiding future research and facilitating the development of effective strategies to overcome multidrug resistance, thus improving therapeutic interventions.
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Affiliation(s)
- Shadi A Badiee
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | - Ugochi H Isu
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | - Ehsaneh Khodadadi
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | - Mahmoud Moradi
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
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2
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Clouser AF, Atkins WM. Long Range Communication between the Drug-Binding Sites and Nucleotide Binding Domains of the Efflux Transporter ABCB1. Biochemistry 2022; 61:730-740. [PMID: 35384651 PMCID: PMC9022228 DOI: 10.1021/acs.biochem.2c00056] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The ABC efflux pump
P-glycoprotein (P-gp) transports a wide variety
of drugs and is inhibited by others. Some drugs stimulate ATP hydrolysis
at the nucleotide binding domains (NBDs) and are transported, others
uncouple ATP hydrolysis and transport, and others inhibit ATP hydrolysis.
The molecular basis for the different behavior of these drugs is not
well understood despite the availability of several structural models
of P-gp complexes with ligands bound. Hypothetically, ligands differentially
alter the conformational dynamics of peptide segments that mediate
the coupling between the drug binding sites and the NBDs. Here, we
explore by hydrogen-deuterium exchange mass spectrometry the dynamic
consequences of a classic substrate and inhibitor, vinblastine and
zosuquidar, binding to mouse P-gp (mdr1a) in lipid nanodiscs. The
dynamics of P-gp in nucleotide-free, pre-hydrolysis, and post-hydrolysis
states in the presence of each drug reveal distinct mechanisms of
ATPase stimulation and implications for transport. For both drugs,
there are common regions affected in a similar manner, suggesting
that particular networks are the key to stimulating ATP hydrolysis.
However, drug binding effects diverge in the post-hydrolysis state,
particularly in the intracellular helices (ICHs 3 and 4) and neighboring
transmembrane helices. The local dynamics and conformational equilibria
in this region are critical for the coupling of drug binding and ATP
hydrolysis and are differentially modulated in the catalytic cycle.
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Affiliation(s)
- Amanda F Clouser
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195-7610, United States
| | - William M Atkins
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195-7610, United States
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3
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Li H, Gong W. Study of Allosteric Transitions of Human P-Glycoprotein by Using the Two-State Anisotropic Network Model. Front Med (Lausanne) 2022; 9:815355. [PMID: 35223913 PMCID: PMC8863969 DOI: 10.3389/fmed.2022.815355] [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: 12/01/2021] [Accepted: 01/04/2022] [Indexed: 11/25/2022] Open
Abstract
Human P-glycoprotein (P-gp) is a kind of ATP-binding cassette (ABC) transporters. Once human P-gp is overexpressed in tumor cells, which can lead to tumor multidrug resistance (MDR). However, the present experimental methods are difficult to obtain the large-scale conformational transition process of human P-gp. In this work, we explored the allosteric pathway of human P-gp from the inward-facing (IF) to the outward-facing (OF) state in the substrate transport process with the two-state anisotropic network model (tANM). These results suggest that the allosteric transitions proceed in a coupled way. The conformational changes of nucleotide-binding domains (NBDs) finally make the transmembrane domains (TMDs) to the OF state via the role of the allosteric propagation of the intracellular helices IH1 and IH2. Additionally, this allosteric pathway is advantageous in energy compared with other methods. This study reveals the conformational transition of P-gp, which contributes to an understanding of the allosteric mechanism of ABC exporters.
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Affiliation(s)
- Hongwu Li
- School of Mathematics and Statistics, Nanyang Normal University, Nanyang, China
| | - Weikang Gong
- Faculty of Environmental and Life Sciences, Beijing University of Technology, Beijing, China
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4
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Wang L, O'Mara ML. Effect of the Force Field on Molecular Dynamics Simulations of the Multidrug Efflux Protein P-Glycoprotein. J Chem Theory Comput 2021; 17:6491-6508. [PMID: 34506133 DOI: 10.1021/acs.jctc.1c00414] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Molecular dynamics (MD) simulations have been used extensively to study P-glycoprotein (P-gp), a flexible multidrug transporter that is a key player in the development of multidrug resistance to chemotherapeutics. A substantial body of literature has grown from simulation studies that have employed various simulation conditions and parameters, including AMBER, CHARMM, OPLS, GROMOS, and coarse-grained force fields, drawing conclusions from simulations spanning hundreds of nanoseconds. Each force field is typically parametrized and validated on different data and observables, usually of small molecules and peptides; there have been few comparisons of force field performance on large protein-membrane systems. Here we compare the conformational ensembles of P-gp embedded in a POPC/cholesterol bilayer generated over 500 ns of replicate simulation with five force fields from popular biomolecular families: AMBER 99SB-ILDN, CHARMM 36, OPLS-AA/L, GROMOS 54A7, and MARTINI. We find considerable differences among the ensembles with little conformational overlap, although they correspond to similar extents to structural data obtained from electron paramagnetic resonance and cross-linking studies. Moreover, each trajectory was still sampling new conformations at a high rate after 500 ns of simulation, suggesting the need for more sampling. This work highlights the need to consider known limitations of the force field used (e.g., biases toward certain secondary structures) and the simulation itself (e.g., whether sufficient sampling has been achieved) when interpreting accumulated results of simulation studies of P-gp and other transport proteins.
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Affiliation(s)
- Lily Wang
- Research School of Chemistry, College of Science, Australian National University, Canberra, ACT 2601, Australia
| | - Megan L O'Mara
- Research School of Chemistry, College of Science, Australian National University, Canberra, ACT 2601, Australia
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5
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Drug Resistance in Osteosarcoma: Emerging Biomarkers, Therapeutic Targets and Treatment Strategies. Cancers (Basel) 2021; 13:cancers13122878. [PMID: 34207685 PMCID: PMC8228414 DOI: 10.3390/cancers13122878] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 06/05/2021] [Indexed: 01/02/2023] Open
Abstract
Simple Summary Despite the adoption of aggressive, multimodal treatment schedules, the cure rate of high-grade osteosarcoma (HGOS) has not significantly improved in the last 30 years. The most relevant problem preventing improvement in HGOS prognosis is drug resistance. Therefore, validated novel biomarkers that help to identify those patients who could benefit from innovative treatment options and the development of drugs enabling personalized therapeutic protocols are necessary. The aim of this review was to give an overview on the most relevant emerging drug resistance-related biomarkers, therapeutic targets and new agents or novel candidate treatment strategies, which have been highlighted and suggested for HGOS to improve the success rate of clinical trials. Abstract High-grade osteosarcoma (HGOS), the most common primary malignant tumor of bone, is a highly aggressive neoplasm with a cure rate of approximately 40–50% in unselected patient populations. The major clinical problems opposing the cure of HGOS are the presence of inherent or acquired drug resistance and the development of metastasis. Since the drugs used in first-line chemotherapy protocols for HGOS and clinical outcome have not significantly evolved in the past three decades, there is an urgent need for new therapeutic biomarkers and targeted treatment strategies, which may increase the currently available spectrum of cure modalities. Unresponsive or chemoresistant (refractory) HGOS patients usually encounter a dismal prognosis, mostly because therapeutic options and drugs effective for rescue treatments are scarce. Tailored treatments for different subgroups of HGOS patients stratified according to drug resistance-related biomarkers thus appear as an option that may improve this situation. This review explores drug resistance-related biomarkers, therapeutic targets and new candidate treatment strategies, which have emerged in HGOS. In addition to consolidated biomarkers, specific attention has been paid to the role of non-coding RNAs, tumor-derived extracellular vesicles, and cancer stem cells as contributors to drug resistance in HGOS, in order to highlight new candidate markers and therapeutic targets. The possible use of new non-conventional drugs to overcome the main mechanisms of drug resistance in HGOS are finally discussed.
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6
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Henderson PJF, Maher C, Elbourne LDH, Eijkelkamp BA, Paulsen IT, Hassan KA. Physiological Functions of Bacterial "Multidrug" Efflux Pumps. Chem Rev 2021; 121:5417-5478. [PMID: 33761243 DOI: 10.1021/acs.chemrev.0c01226] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bacterial multidrug efflux pumps have come to prominence in human and veterinary pathogenesis because they help bacteria protect themselves against the antimicrobials used to overcome their infections. However, it is increasingly realized that many, probably most, such pumps have physiological roles that are distinct from protection of bacteria against antimicrobials administered by humans. Here we undertake a broad survey of the proteins involved, allied to detailed examples of their evolution, energetics, structures, chemical recognition, and molecular mechanisms, together with the experimental strategies that enable rapid and economical progress in understanding their true physiological roles. Once these roles are established, the knowledge can be harnessed to design more effective drugs, improve existing microbial production of drugs for clinical practice and of feedstocks for commercial exploitation, and even develop more sustainable biological processes that avoid, for example, utilization of petroleum.
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Affiliation(s)
- Peter J F Henderson
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Claire Maher
- School of Environmental and Life Sciences, University of Newcastle, Callaghan 2308, New South Wales, Australia
| | - Liam D H Elbourne
- Department of Biomolecular Sciences, Macquarie University, Sydney 2109, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
| | - Bart A Eijkelkamp
- College of Science and Engineering, Flinders University, Bedford Park 5042, South Australia, Australia
| | - Ian T Paulsen
- Department of Biomolecular Sciences, Macquarie University, Sydney 2109, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
| | - Karl A Hassan
- School of Environmental and Life Sciences, University of Newcastle, Callaghan 2308, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
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7
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Structural dynamics of ABC transporters: molecular simulation studies. Biochem Soc Trans 2021; 49:405-414. [PMID: 33634827 DOI: 10.1042/bst20200710] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 12/31/2022]
Abstract
The biological activities of living organisms involve various inputs and outputs. The ATP-driven substances (biomolecules) responsible for these kinds of activities through membrane (i.e. uptake and efflux of substrates) include ATP-binding cassette (ABC) transporters, some of which play important roles in multidrug resistance. The basic architecture of ABC transporters comprises transmembrane domains (TMDs) and nucleotide-binding domains (NBDs). The functional dynamics (substrate transport) of ABC transporters are realized by concerted motions, such as NBD dimerization, mechanical transmission via coupling helices (CHs), and the translocation of substrates through TMDs, which are induced by the binding and/or hydrolysis of ATP molecules and substrates. In this mini-review, we briefly discuss recent progresses in the structural dynamics as revealed by molecular simulation studies at all-atom (AA), coarse-grained (CG), and quantum mechanics/molecular mechanics (QM/MM) levels.
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8
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Tangella LP, Arooj M, Deplazes E, Gray ES, Mancera RL. Identification and characterisation of putative drug binding sites in human ATP-binding cassette B5 (ABCB5) transporter. Comput Struct Biotechnol J 2020; 19:691-704. [PMID: 33510870 PMCID: PMC7817430 DOI: 10.1016/j.csbj.2020.12.042] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 12/25/2020] [Accepted: 12/26/2020] [Indexed: 12/24/2022] Open
Abstract
The human ATP-binding cassette B5 (ABCB5) transporter, a member of the ABC transporter superfamily, is linked to chemoresistance in tumour cells by drug effluxion. However, little is known about its structure and drug-binding sites. In this study, we generated an atomistic model of the full-length human ABCB5 transporter with the highest quality using the X-ray crystal structure of mouse ABCB1 (Pgp1), a close homologue of ABCB5 and a well-studied member of the ABC family. Molecular dynamics simulations were used to validate the atomistic model of ABCB5 and characterise its structural properties in model cell membranes. Molecular docking simulations of known ABCB5 substrates such as taxanes, anthracyclines, camptothecin and etoposide were then used to identify at least three putative binding sites for chemotherapeutic drugs transported by ABCB5. The location of these three binding sites is predicted to overlap with the corresponding binding sites in Pgp1. These findings will serve as the basis for future in vitro studies to validate the nature of the identified substrate-binding sites in the full-length ABCB5 transporter.
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Affiliation(s)
- Lokeswari P Tangella
- School of Medical and Health Sciences, Edith Cowan University, Perth, WA 6027, Australia
| | - Mahreen Arooj
- Department of Chemistry, College of Sciences, University of Sharjah, Sharjah 27272, United Arab Emirates
| | - Evelyne Deplazes
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute and Curtin Institute for Computation, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.,School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Elin S Gray
- School of Medical and Health Sciences, Edith Cowan University, Perth, WA 6027, Australia
| | - Ricardo L Mancera
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute and Curtin Institute for Computation, Curtin University, GPO Box U1987, Perth, WA 6845, Australia
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9
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Stockner T, Gradisch R, Schmitt L. The role of the degenerate nucleotide binding site in type I ABC exporters. FEBS Lett 2020; 594:3815-3838. [PMID: 33179257 PMCID: PMC7756269 DOI: 10.1002/1873-3468.13997] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/26/2020] [Accepted: 10/15/2020] [Indexed: 12/18/2022]
Abstract
ATP‐binding cassette (ABC) transporters are fascinating molecular machines that are capable of transporting a large variety of chemically diverse compounds. The energy required for translocation is derived from binding and hydrolysis of ATP. All ABC transporters share a basic architecture and are composed of two transmembrane domains and two nucleotide binding domains (NBDs). The latter harbor all conserved sequence motifs that hallmark the ABC transporter superfamily. The NBDs form the nucleotide binding sites (NBSs) in their interface. Transporters with two active NBSs are called canonical transporters, while ABC exporters from eukaryotic organisms, including humans, frequently have a degenerate NBS1 containing noncanonical residues that strongly impair ATP hydrolysis. Here, we summarize current knowledge on degenerate ABC transporters. By integrating structural information with biophysical and biochemical evidence of asymmetric function, we develop a model for the transport cycle of degenerate ABC transporters. We will elaborate on the unclear functional advantages of a degenerate NBS.
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Affiliation(s)
- Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Ralph Gradisch
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University, Düsseldorf, Germany
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10
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Zhang Y, Han Z, Li C. Molecular insight into human P-glycoprotein allosteric transition from outward- to inward-facing state. Chem Phys 2020. [DOI: 10.1016/j.chemphys.2020.110823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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11
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Nagy T, Tóth Á, Telbisz Á, Sarkadi B, Tordai H, Tordai A, Hegedűs T. The transport pathway in the ABCG2 protein and its regulation revealed by molecular dynamics simulations. Cell Mol Life Sci 2020; 78:2329-2339. [PMID: 32979053 PMCID: PMC7966132 DOI: 10.1007/s00018-020-03651-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 09/01/2020] [Accepted: 09/15/2020] [Indexed: 02/06/2023]
Abstract
Atomic-level structural insight on the human ABCG2 membrane protein, a pharmacologically important transporter, has been recently revealed by several key papers. In spite of the wealth of structural data, the pathway of transmembrane movement for the large variety of structurally different ABCG2 substrates and the physiological lipid regulation of the transporter has not been elucidated. The complex molecular dynamics simulations presented here may provide a breakthrough in understanding the steps of the substrate transport process and its regulation by cholesterol. Our analysis revealed drug binding cavities other than the central binding site and delineated a putative dynamic transport pathway for substrates with variable structures. We found that membrane cholesterol accelerated drug transport by promoting the closure of cytoplasmic protein regions. Since ABCG2 is present in all major biological barriers and drug-metabolizing organs, influences the pharmacokinetics of numerous clinically applied drugs, and plays a key role in uric acid extrusion, this information may significantly promote a reliable prediction of clinically important substrate characteristics and drug-drug interactions.
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Affiliation(s)
- Tamás Nagy
- Department of Biophysics and Radiation Biology, Semmelweis University, Tuzolto u. 37-47, 1094, Budapest, Hungary
| | - Ágota Tóth
- Department of Biophysics and Radiation Biology, Semmelweis University, Tuzolto u. 37-47, 1094, Budapest, Hungary
| | - Ágnes Telbisz
- Institute of Enzymology, Research Centre for Natural Sciences, Magyar Tudosok krt. 2, 1117, Budapest, Hungary
| | - Balázs Sarkadi
- Department of Biophysics and Radiation Biology, Semmelweis University, Tuzolto u. 37-47, 1094, Budapest, Hungary
- Institute of Enzymology, Research Centre for Natural Sciences, Magyar Tudosok krt. 2, 1117, Budapest, Hungary
| | - Hedvig Tordai
- Department of Biophysics and Radiation Biology, Semmelweis University, Tuzolto u. 37-47, 1094, Budapest, Hungary
| | - Attila Tordai
- Department of Transfusion Medicine, Semmelweis University, Nagyvarad ter 4, 1089, Budapest, Hungary
| | - Tamás Hegedűs
- Department of Biophysics and Radiation Biology, Semmelweis University, Tuzolto u. 37-47, 1094, Budapest, Hungary.
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12
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Jiang Y, Wang Z, Duan W, Liu L, Si M, Chen X, Fang CJ. The critical size of gold nanoparticles for overcoming P-gp mediated multidrug resistance. NANOSCALE 2020; 12:16451-16461. [PMID: 32790812 PMCID: PMC7430045 DOI: 10.1039/d0nr03226c] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Multidrug resistance (MDR) remains a huge obstacle during cancer treatment. One of the most studied MDR mechanisms is P-glycoprotein (P-gp) mediated drug efflux. Based on the three-dimensional structural characteristics of P-gp, gold nanoparticles (AuNPs) with average sizes of 4.1 nm and 5.4 nm were designed for the construction of nanodrug delivery systems (NanoDDSs), with the anticancer molecules 2-(9-anthracenylmethylene)-hydrazinecarbothioamide (ANS) and 6-mercaptopurine (6-MP) modified on the AuNP surfaces through the thiol group. In vitro cytotoxicity results suggested that the larger sized AuNPs can effectively decrease the drug resistance index of MCF-7/ADR cells to ∼2. Verapamil and P-gp antibody competitive experiments, combined with the cellular uptake of AuNPs, indicated that larger NanoDDSs were more conducive to intracellular drug accumulation and thus had improved anticancer activities, due to a size mismatch between the nanoparticles and the active site of P-gp, and, therefore, reduced drug efflux was seen. Measurements of ATPase activity and intracellular ATP levels indicated that the larger nanoparticles do not bind well to P-gp, thus avoiding effective recognition by P-gp. This was further evidenced by the observation that 4.1 nm and 5.4 nm NanoDDS-treated MCF-7/ADR cells showed remarkable differences in energy-related metabolic pathways. Therefore, the critical size of AuNPs for overcoming MDR was identified to be between 4.1 nm and 5.4 nm. This provides a more accurate description of the composite dimension requirements for NanoDDSs that are designed to overcome MDR.
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Affiliation(s)
- Yuqian Jiang
- School of Pharmaceutical Sciences, Capital Medical University, Beijing 100069, China.
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Mollazadeh S, Hadizadeh F, Ferreira RJ. Theoretical studies on 1,4-dihydropyridine derivatives as P-glycoprotein allosteric inhibitors: insights on symmetry and stereochemistry. J Biomol Struct Dyn 2020; 39:4752-4763. [DOI: 10.1080/07391102.2020.1780942] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Shirin Mollazadeh
- Department of Medicinal Chemistry, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Farzin Hadizadeh
- Department of Medicinal Chemistry, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ricardo J. Ferreira
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
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14
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Coencapsulation of disulfiram and doxorubicin in liposomes strongly reverses multidrug resistance in breast cancer cells. Int J Pharm 2020; 580:119191. [DOI: 10.1016/j.ijpharm.2020.119191] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 02/06/2020] [Accepted: 02/28/2020] [Indexed: 12/19/2022]
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15
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Wise JG, Nanayakkara AK, Aljowni M, Chen G, De Oliveira MC, Ammerman L, Olengue K, Lippert AR, Vogel PD. Optimizing Targeted Inhibitors of P-Glycoprotein Using Computational and Structure-Guided Approaches. J Med Chem 2019; 62:10645-10663. [PMID: 31702922 DOI: 10.1021/acs.jmedchem.9b00966] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Overexpression of ABC transporters like P-glycoprotein (P-gp) has been correlated with resistances in cancer chemotherapy. Intensive efforts to identify P-gp inhibitors for use in combination therapy have not led to clinically approved inhibitors to date. Here, we describe computational approaches combined with structure-based design to improve the characteristics of a P-gp inhibitor previously identified by us. This hit compound represents a novel class of P-gp inhibitors that specifically targets and inhibits P-gp ATP hydrolysis while not being transported by the pump. We describe here a new program for virtual chemical synthesis and computational assessment, ChemGen, to produce hit compound variants with improved binding characteristics. The chemical syntheses of several variants, efficacy in reversing multidrug resistance in cell culture, and biochemical assessment of the inhibition mechanism are described. The usefulness of the computational predictions of binding characteristics of the inhibitor variants is discussed and compared to more traditional structure-based approaches.
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16
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Arana MR, Altenberg GA. ATP-binding Cassette Exporters: Structure and Mechanism with a Focus on P-glycoprotein and MRP1. Curr Med Chem 2019; 26:1062-1078. [PMID: 29022498 DOI: 10.2174/0929867324666171012105143] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/03/2017] [Accepted: 08/03/2017] [Indexed: 12/11/2022]
Abstract
BACKGROUND Proteins that belong to the ATP-binding cassette superfamily include transporters that mediate the efflux of substrates from cells. Among these exporters, P-glycoprotein and MRP1 are involved in cancer multidrug resistance, protection from endo and xenobiotics, determination of drug pharmacokinetics, and the pathophysiology of a variety of disorders. OBJECTIVE To review the information available on ATP-binding cassette exporters, with a focus on Pglycoprotein, MRP1 and related proteins. We describe tissue localization and function of these transporters in health and disease, and discuss the mechanisms of substrate transport. We also correlate recent structural information with the function of the exporters, and discuss details of their molecular mechanism with a focus on the nucleotide-binding domains. METHODS Evaluation of selected publications on the structure and function of ATP-binding cassette proteins. CONCLUSIONS Conformational changes on the nucleotide-binding domains side of the exporters switch the accessibility of the substrate-binding pocket between the inside and outside, which is coupled to substrate efflux. However, there is no agreement on the magnitude and nature of the changes at the nucleotide- binding domains side that drive the alternate-accessibility. Comparison of the structures of Pglycoprotein and MRP1 helps explain differences in substrate selectivity and the bases for polyspecificity. P-glycoprotein substrates are hydrophobic and/or weak bases, and polyspecificity is explained by a flexible hydrophobic multi-binding site that has a few acidic patches. MRP1 substrates are mostly organic acids, and its polyspecificity is due to a single bipartite binding site that is flexible and displays positive charge.
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Affiliation(s)
- Maite Rocío Arana
- Instituto de Fisiología Experimental, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, CONICET, Suipacha 570, 2000 Rosario, Argentina
| | - Guillermo Alejandro Altenberg
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas 79430-6551, United States
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17
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Buondonno I, Gazzano E, Tavanti E, Chegaev K, Kopecka J, Fanelli M, Rolando B, Fruttero R, Gasco A, Hattinger C, Serra M, Riganti C. Endoplasmic reticulum-targeting doxorubicin: a new tool effective against doxorubicin-resistant osteosarcoma. Cell Mol Life Sci 2019; 76:609-625. [PMID: 30430199 PMCID: PMC11105372 DOI: 10.1007/s00018-018-2967-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 09/26/2018] [Accepted: 11/05/2018] [Indexed: 12/29/2022]
Abstract
Doxorubicin is one of the most effective drugs for the first-line treatment of high-grade osteosarcoma. Several studies have demonstrated that the major cause for doxorubicin resistance in osteosarcoma is the increased expression of the drug efflux transporter ABCB1/P-glycoprotein (Pgp). We recently identified a library of H2S-releasing doxorubicins (Sdox) that were more effective than doxorubicin against resistant osteosarcoma cells. Here we investigated the molecular mechanisms of the higher efficacy of Sdox in human osteosarcoma cells with increasing resistance to doxorubicin. Differently from doxorubicin, Sdox preferentially accumulated within the endoplasmic reticulum (ER), and its accumulation was only modestly reduced in Pgp-expressing osteosarcoma cells. The increase in doxorubicin resistance was paralleled by the progressive down-regulation of genes of ER-associated protein degradation/ER-quality control (ERAD/ERQC), two processes that remove misfolded proteins and protect cell from ER stress-triggered apoptosis. Sdox, that sulfhydrated ER-associated proteins and promoted their subsequent ubiquitination, up-regulated ERAD/ERQC genes. This up-regulation, however, was insufficient to protect cells, since Sdox activated ER stress-dependent apoptotic pathways, e.g., the C/EBP-β LIP/CHOP/PUMA/caspases 12-7-3 axis. Sdox also promoted the sulfhydration of Pgp that was subsequently ubiquitinated: this process further enhanced Sdox retention and toxicity in resistant cells. Our work suggests that Sdox overcomes doxorubicin resistance in osteosarcoma cells by at least two mechanisms: it induces the degradation of Pgp following its sulfhydration and produces a huge misfolding of ER-associated proteins, triggering ER-dependent apoptosis. Sdox may represent the prototype of innovative anthracyclines, effective against doxorubicin-resistant/Pgp-expressing osteosarcoma cells by perturbing the ER functions.
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Affiliation(s)
- Ilaria Buondonno
- Department of Oncology, University of Torino, Via Santena 5/bis, 10126, Torino, Italy
| | - Elena Gazzano
- Department of Oncology, University of Torino, Via Santena 5/bis, 10126, Torino, Italy
| | - Elisa Tavanti
- Laboratory of Experimental Oncology, Pharmacogenomics and Pharmacogenetics Research Unit, Orthopaedic Rizzoli Institute I.R.C.C.S, Bologna, Italy
| | - Konstantin Chegaev
- Department of Drug Science and Technology, University of Torino, Torino, Italy
| | - Joanna Kopecka
- Department of Oncology, University of Torino, Via Santena 5/bis, 10126, Torino, Italy
| | - Marilù Fanelli
- Laboratory of Experimental Oncology, Pharmacogenomics and Pharmacogenetics Research Unit, Orthopaedic Rizzoli Institute I.R.C.C.S, Bologna, Italy
| | - Barbara Rolando
- Department of Drug Science and Technology, University of Torino, Torino, Italy
| | - Roberta Fruttero
- Department of Drug Science and Technology, University of Torino, Torino, Italy
| | - Alberto Gasco
- Department of Drug Science and Technology, University of Torino, Torino, Italy
| | - Claudia Hattinger
- Laboratory of Experimental Oncology, Pharmacogenomics and Pharmacogenetics Research Unit, Orthopaedic Rizzoli Institute I.R.C.C.S, Bologna, Italy
| | - Massimo Serra
- Laboratory of Experimental Oncology, Pharmacogenomics and Pharmacogenetics Research Unit, Orthopaedic Rizzoli Institute I.R.C.C.S, Bologna, Italy
| | - Chiara Riganti
- Department of Oncology, University of Torino, Via Santena 5/bis, 10126, Torino, Italy.
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18
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Zhang YT, Yu YQ, Yan XX, Wang WJ, Tian XT, Wang L, Zhu WL, Gong LK, Pan GY. Different structures of berberine and five other protoberberine alkaloids that affect P-glycoprotein-mediated efflux capacity. Acta Pharmacol Sin 2019; 40:133-142. [PMID: 30442987 DOI: 10.1038/s41401-018-0183-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 10/10/2018] [Indexed: 11/09/2022] Open
Abstract
Berberine, berberrubine, thalifendine, demethyleneberberine, jatrorrhizine, and columbamine are six natural protoberberine alkaloid (PA) compounds that display extensive pharmacological properties and share the same protoberberine molecular skeleton with only slight substitution differences. The oral delivery of most PAs is hindered by their poor bioavailability, which is largely caused by P-glycoprotein (P-gp)-mediated drug efflux. Meanwhile, P-gp undergoes large-scale conformational changes (from an inward-facing to an outward-facing state) when transporting substrates, and these changes might strongly affect the P-gp-binding specificity. To confirm whether these six compounds are substrates of P-gp, to investigate the differences in efflux capacity caused by their trivial structural differences and to reveal the key to increasing their binding affinity to P-gp, we conducted a series of in vivo, in vitro, and in silico assays. Here, we first confirmed that all six compounds were substrates of P-gp by comparing the drug concentrations in wild-type and P-gp-knockout mice in vivo. The efflux capacity (net efflux) ranked as berberrubine > berberine > columbamine ~ jatrorrhizine > thalifendine > demethyleneberberine based on in vitro transport studies in Caco-2 monolayers. Using molecular dynamics simulation and molecular docking techniques, we determined the transport pathways of the six compounds and their binding affinities to P-gp. The results suggested that at the early binding stage, different hydrophobic and electrostatic interactions collectively differentiate the binding affinities of the compounds to P-gp, whereas electrostatic interactions are the main determinant at the late release stage. In addition to hydrophobic interactions, hydrogen bonds play an important role in discriminating the binding affinities.
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19
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Allosteric Role of Substrate Occupancy Toward the Alignment of P-glycoprotein Nucleotide Binding Domains. Sci Rep 2018; 8:14643. [PMID: 30279588 PMCID: PMC6168518 DOI: 10.1038/s41598-018-32815-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 09/15/2018] [Indexed: 01/16/2023] Open
Abstract
P-glycoprotein (Pgp) is an ATP-binding cassette transporter that eliminates toxins from the cell but causes multidrug resistance in chemotherapies. The crystal structures of Pgp revealed drug-like compounds bound to an inward-facing conformation in which the energy-harnessing nucleotide binding domains (NBDs) were widely separated with no interfacial interaction. Following drug binding, inward-facing Pgp must transition to an NBD dimer conformation to achieve ATP binding and hydrolysis at canonical sites defined by both halves of the interface. However, given the high degree of flexibility shown for this transporter, it is difficult to envision how NBDs overcome entropic considerations for achieving proper alignment in order to form the canonical ATP binding site. We explored the hypothesis that substrate occupancy of the polyspecific drug-binding cavity plays a role in the proper alignment of NBDs using computational approaches. We conducted twelve atomistic molecular dynamics (MD) simulations (100-300 ns) on inward-facing Pgp in a lipid bilayer with and without small molecule substrates to ascertain effects of drug occupancy on NBD dimerization. Both apo- and drug-occupied simulations showed NBDs approaching each other compared to the crystal structures. Apo-Pgp reached a pseudo-dimerization in which NBD signature motifs for ATP binding exhibited a significant misalignment during closure. In contrast, occupancy of three established substrates positioned by molecular docking achieved NBD alignment that was much more compatible with a canonical NBD dimerization trajectory. Additionally, aromatic amino acids, known to confer the polyspecific drug-binding characteristic of the internal pocket, may also govern polyspecific drug access to the cavity. The enrichment of aromatics comprising the TM4-TM6 portal suggested a preferential pathway over the aromatic-poor TM10-TM12 for lateral drug entry from the lipid bilayer. Our study also suggested that drug polyspecificity is enhanced due to a synergism between multiple drug-domain interactions involving 36 residues identified in TM1, 5, 6, 7, 11 and 12.
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20
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Sajid A, Lusvarghi S, Chufan EE, Ambudkar SV. Evidence for the critical role of transmembrane helices 1 and 7 in substrate transport by human P-glycoprotein (ABCB1). PLoS One 2018; 13:e0204693. [PMID: 30265721 PMCID: PMC6161881 DOI: 10.1371/journal.pone.0204693] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 09/12/2018] [Indexed: 12/15/2022] Open
Abstract
P-glycoprotein (P-gp) is an ABC transporter that exports many amphipathic or hydrophobic compounds, including chemically and functionally dissimilar anticancer drugs, from cells. To understand the role of transmembrane helices (TMH) 1 and 7 in drug-binding and transport, we selected six residues from both TMH1 (V53, I59, I60, L65, M68 and F72) and TMH7 (V713, I719, I720, Q725, F728 and F732); and substituted them with alanine by gene synthesis to generate a variant termed "TMH1,7 mutant P-gp". The expression and function of TMH1,7 mutant P-gp with twelve mutations was characterized using the BacMam baculovirus-HeLa cell expression system. The expression and conformation of TMH1,7 mutant P-gp was not altered by the introduction of the twelve mutations, as confirmed by using the human P-gp-specific antibodies UIC2, MRK16 and 4E3. We tested 25 fluorescently-labeled substrates and found that only three substrates, NBD-cyclosporine A, Rhod-2-AM and X-Rhod-1-AM were transported by the TMH1,7 mutant. The basal ATPase activity of TMH1,7 mutant P-gp was lower (40-50%) compared to wild-type (WT) P-gp, despite similar level of expression. Although most of the substrates modulate ATPase activity of P-gp, the activity of TMH1,7 mutant transporter was not significantly modulated by any of the tested substrates. Docking of selected substrates in homology models showed comparable docking scores for the TMH1,7 mutant and WT P-gp, although the binding conformations were different. Both the ATPase assay and in silico docking analyses suggest that the interactions with residues in the drug-binding pocket are altered as a consequence of the mutations. We demonstrate that it is possible to generate a variant of P-gp with a loss of broad substrate specificity and propose that TMH1 and TMH7 play a critical role in the drug efflux function of this multidrug transporter.
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Affiliation(s)
- Andaleeb Sajid
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sabrina Lusvarghi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Eduardo E. Chufan
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Suresh V. Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
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21
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Zhang Y, Gong W, Wang Y, Liu Y, Li C. Exploring movement and energy in human P-glycoprotein conformational rearrangement. J Biomol Struct Dyn 2018; 37:1104-1119. [PMID: 29620438 DOI: 10.1080/07391102.2018.1461133] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Human P-glycoprotein (P-gp), a kind of ATP-Binding Cassette transporter, can export a diverse variety of anti-cancer drugs out of the tumor cell. Its overexpression is one of the main reasons for the multidrug resistance (MDR) of tumor cells. It has been confirmed that during the substrate transport process, P-gp experiences a large-scale structural rearrangement from the inward- to outward-facing states. However, the mechanism of how the nucleotide-binding domains (NBDs) control the transmembrane domains (TMDs) to open towards the periplasm in the outward-facing state has not yet been fully characterized. Herein, targeted molecular dynamics simulations were performed to explore the conformational rearrangement of human P-gp. The results show that the allosteric process proceeds in a coupled way, and first the transition is driven by the NBDs, and then transmitted to the cytoplasmic parts of TMDs, finally to the periplasmic parts. The trajectories show that besides the translational motions, the NBDs undergo a rotation movement, which mainly occurs in xy plane and ensures the formation of the correct ATP-binding pockets. The analyses on the interaction energies between the six structure segments (cICLs) from the TMDs and NBDs reveal that their subtle energy differences play an important role in causing the periplasmic parts of the transmembrane helices to separate from each other in the established directions and in appropriate amplitudes. This conclusion can explain the two experimental phenomena about human P-gp in some extent. These studies have provided a detailed exploration into human P-gp rearrangement process and given an energy insight into the TMD reorientation during P-gp transition.
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Affiliation(s)
- Yue Zhang
- a College of Life Science and Bioengineering , Beijing University of Technology , Beijing , 100124 , China
| | - Weikang Gong
- a College of Life Science and Bioengineering , Beijing University of Technology , Beijing , 100124 , China
| | - Yan Wang
- b Key Laboratory of Molecular Biophysics of the Ministry of Education, School of Life Science and Technology , Huazhong University of Science and Technology , Wuhan , Hubei , 430074 , China
| | - Yang Liu
- a College of Life Science and Bioengineering , Beijing University of Technology , Beijing , 100124 , China
| | - Chunhua Li
- a College of Life Science and Bioengineering , Beijing University of Technology , Beijing , 100124 , China
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22
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Li MJ, Guttman M, Atkins WM. Conformational dynamics of P-glycoprotein in lipid nanodiscs and detergent micelles reveal complex motions on a wide time scale. J Biol Chem 2018; 293:6297-6307. [PMID: 29511086 DOI: 10.1074/jbc.ra118.002190] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 02/26/2018] [Indexed: 11/06/2022] Open
Abstract
P-glycoprotein (P-gp) is a highly substrate-promiscuous efflux transporter that plays a critical role in drug disposition. P-gp utilizes ATP hydrolysis by nucleotide-binding domains (NBDs) to drive transitions between inward-facing (IF) conformations that bind drugs and outward-facing (OF) conformations that release them to the extracellular solution. However, the details of the protein dynamics within either macroscopic IF or OF conformation remain uncharacterized, and the functional role of local dynamics has not been determined. In this work we measured the local dynamics of the IF state of P-gp in lipid nanodiscs and in detergent solution by hydrogen-deuterium (H/D) exchange MS. We observed "EX1 exchange kinetics," or bimodal kinetics, for several peptides distributed in both NBDs, particularly for P-gp in the lipid nanodiscs. Remarkably, the EX1 kinetics occurred on several time scales, ranging from seconds to hours, suggesting highly complex, and correlated, motions. The results indicate at least three distinct conformational states in the ligand-free P-gp and suggest a rough conformational landscape. Addition of excess ATP and vanadate, to favor the OF conformations, caused a generalized, but modest, decrease in H/D exchange throughout the NBDs and slowed the EX1 kinetic transitions of several peptides. The functional implications of the results are consistent with the possibility that conformational selection provides a source of substrate promiscuity.
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Affiliation(s)
- Mavis Jiarong Li
- From the Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195-7610
| | - Miklos Guttman
- From the Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195-7610
| | - William M Atkins
- From the Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195-7610
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23
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Condic-Jurkic K, Subramanian N, Mark AE, O’Mara ML. The reliability of molecular dynamics simulations of the multidrug transporter P-glycoprotein in a membrane environment. PLoS One 2018; 13:e0191882. [PMID: 29370310 PMCID: PMC5785007 DOI: 10.1371/journal.pone.0191882] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 01/13/2018] [Indexed: 11/19/2022] Open
Abstract
Despite decades of research, the mechanism of action of the ABC multidrug transporter P-glycoprotein (P-gp) remains elusive. Due to experimental limitations, many researchers have turned to molecular dynamics simulation studies in order to investigate different aspects of P-gp function. However, such studies are challenging and caution is required when interpreting the results. P-gp is highly flexible and the time scale on which it can be simulated is limited. There is also uncertainty regarding the accuracy of the various crystal structures available, let alone the structure of the protein in a physiologically relevant environment. In this study, three alternative structural models of mouse P-gp (3G5U, 4KSB, 4M1M), all resolved to 3.8 Å, were used to initiate sets of simulations of P-gp in a membrane environment in order to determine: a) the sensitivity of the results to differences in the starting configuration; and b) the extent to which converged results could be expected on the times scales commonly simulated for this system. The simulations suggest that the arrangement of the nucleotide binding domains (NBDs) observed in the crystal structures is not stable in a membrane environment. In all simulations, the NBDs rapidly associated (within 10 ns) and changes within the transmembrane helices were observed. The secondary structure within the transmembrane domain was best preserved in the 4M1M model under the simulation conditions used. However, the extent to which replicate simulations diverged on a 100 to 200 ns timescale meant that it was not possible to draw definitive conclusions as to which structure overall was most stable, or to obtain converged and reliable results for any of the properties examined. The work brings into question the reliability of conclusions made in regard to the nature of specific interactions inferred from previous simulation studies on this system involving similar sampling times. It also highlights the need to demonstrate the statistical significance of any results obtained in simulations of large flexible proteins, especially where the initial structure is uncertain.
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Affiliation(s)
- Karmen Condic-Jurkic
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, ACT 4072, Australia
| | - Nandhitha Subramanian
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, ACT 4072, Australia
| | - Alan E. Mark
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, ACT 4072, Australia
| | - Megan L. O’Mara
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
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24
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Szöllősi D, Szakács G, Chiba P, Stockner T. Dissecting the Forces that Dominate Dimerization of the Nucleotide Binding Domains of ABCB1. Biophys J 2018; 114:331-342. [PMID: 29401431 PMCID: PMC5984967 DOI: 10.1016/j.bpj.2017.11.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 10/11/2017] [Accepted: 11/14/2017] [Indexed: 01/10/2023] Open
Abstract
P-glycoprotein, also known as multidrug resistance protein 1 or ABCB1, can export a wide range of chemically unrelated compounds, including chemotherapeutic drugs. ABCB1 consists of two transmembrane domains that form the substrate binding and translocation domain, and of two cytoplasmic nucleotide binding domains (NBDs) that energize substrate transport by ATP binding and hydrolysis. ATP binding triggers dimerization of the NBDs, which switches the transporter from an inward facing to an outward facing transmembrane domain conformation. We performed MD simulations to study the dynamic behavior of the NBD dimer in the presence or absence of nucleotides. In the apo configuration, the NBDs were overall attractive to each other as shown in the potential of mean force profile, but the energy well was shallow and broad. In contrast, a sharp and deep energy minimum (∼-42 kJ/mol) was found in the presence of ATP, leading to a well-defined conformation. Motif interaction network analyses revealed that ATP stabilizes the NBD dimer by serving as the central hub for interdomain connections. Simulations showed that forces promoting dimerization are multilayered, dominated by electrostatic interactions between the nucleotide and conserved amino acids of the signature sequence and the Walker A motif. In addition, direct and water-bridged hydrogen bonds between NBDs provided conformation-defining interactions. Importantly, we characterized a largely unrecognized but essential contribution from hydrophobic interactions between the adenine moiety of the nucleotides and a hydrophobic surface of the X-loop to the stabilization of the nucleotide-bound NBD dimer. These hydrophobic interactions lead to a sharp energy minimum, thereby conformationally restricting the nucleotide-bound state.
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Affiliation(s)
- Dániel Szöllősi
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Gergely Szakács
- Institute of Cancer Research, Medical University of Vienna, Vienna, Austria
| | - Peter Chiba
- Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria
| | - Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria.
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25
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Liu T, Liu X, Xiong H, Xu C, Yao J, Zhu X, Zhou J, Yao J. Mechanisms of TPGS and its derivatives inhibiting P-glycoprotein efflux pump and application for reversing multidrug resistance in hepatocellular carcinoma. Polym Chem 2018. [DOI: 10.1039/c8py00344k] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have developed a TPGS–GA conjugate and TPGS–LA conjugate which possess more effective P-gp inhibition compared to TPGS because of the enhancement of hydrophilicity and negative charge.
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Affiliation(s)
- Tengfei Liu
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Ability of Biopharmaceuticals
- Department of Pharmaceutics
- China Pharmaceutical University
- Nanjing 210009
- PR China
| | - Xiaoyan Liu
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Ability of Biopharmaceuticals
- Department of Pharmaceutics
- China Pharmaceutical University
- Nanjing 210009
- PR China
| | - Hui Xiong
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Ability of Biopharmaceuticals
- Department of Pharmaceutics
- China Pharmaceutical University
- Nanjing 210009
- PR China
| | - Cheng Xu
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Ability of Biopharmaceuticals
- Department of Pharmaceutics
- China Pharmaceutical University
- Nanjing 210009
- PR China
| | - Jianxu Yao
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Ability of Biopharmaceuticals
- Department of Pharmaceutics
- China Pharmaceutical University
- Nanjing 210009
- PR China
| | - Xiumei Zhu
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Ability of Biopharmaceuticals
- Department of Pharmaceutics
- China Pharmaceutical University
- Nanjing 210009
- PR China
| | - Jianping Zhou
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Ability of Biopharmaceuticals
- Department of Pharmaceutics
- China Pharmaceutical University
- Nanjing 210009
- PR China
| | - Jing Yao
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Ability of Biopharmaceuticals
- Department of Pharmaceutics
- China Pharmaceutical University
- Nanjing 210009
- PR China
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26
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Szöllősi D, Rose-Sperling D, Hellmich UA, Stockner T. Comparison of mechanistic transport cycle models of ABC exporters. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:818-832. [PMID: 29097275 PMCID: PMC7610611 DOI: 10.1016/j.bbamem.2017.10.028] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 10/23/2017] [Accepted: 10/25/2017] [Indexed: 12/25/2022]
Abstract
ABC (ATP binding cassette) transporters, ubiquitous in all kingdoms of life, carry out essential substrate transport reactions across cell membranes. Their transmembrane domains bind and translocate substrates and are connected to a pair of nucleotide binding domains, which bind and hydrolyze ATP to energize import or export of substrates. Over four decades of investigations into ABC transporters have revealed numerous details from atomic-level structural insights to their functional and physiological roles. Despite all these advances, a comprehensive understanding of the mechanistic principles of ABC transporter function remains elusive. The human multidrug resistance transporter ABCB1, also referred to as P-glycoprotein (P-gp), is one of the most intensively studied ABC exporters. Using ABCB1 as the reference point, we aim to compare the dominating mechanistic models of substrate transport and ATP hydrolysis for ABC exporters and to highlight the experimental and computational evidence in their support. In particular, we point out in silico studies that enhance and complement available biochemical data. “This article is part of a Special Issue entitled: Beyond the Structure Function Horizon of Membrane Proteins edited by Ute Hellmich, Rupak Doshi and Benjamin McIlwain.”
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Affiliation(s)
- Dániel Szöllősi
- Medical University of Vienna, Institute of Pharmacology, Waehringerstr. 13A, Vienna 1090, Austria
| | - Dania Rose-Sperling
- Johannes Gutenberg-University, Department of Pharmacy and Biochemistry, Johann-Joachim-Becher-Weg 30, Mainz 55128, Germany; Centre for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, Max von Laue-Str. 9, 60438 Frankfurt am Main, Germany
| | - Ute A Hellmich
- Johannes Gutenberg-University, Department of Pharmacy and Biochemistry, Johann-Joachim-Becher-Weg 30, Mainz 55128, Germany; Centre for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, Max von Laue-Str. 9, 60438 Frankfurt am Main, Germany
| | - Thomas Stockner
- Medical University of Vienna, Institute of Pharmacology, Waehringerstr. 13A, Vienna 1090, Austria.
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27
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Zoghbi ME, Mok L, Swartz DJ, Singh A, Fendley GA, Urbatsch IL, Altenberg GA. Substrate-induced conformational changes in the nucleotide-binding domains of lipid bilayer-associated P-glycoprotein during ATP hydrolysis. J Biol Chem 2017; 292:20412-20424. [PMID: 29018094 DOI: 10.1074/jbc.m117.814186] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 09/25/2017] [Indexed: 11/06/2022] Open
Abstract
P-glycoprotein (Pgp) is an efflux pump important in multidrug resistance of cancer cells and in determining drug pharmacokinetics. Pgp is a prototype ATP-binding cassette transporter with two nucleotide-binding domains (NBDs) that bind and hydrolyze ATP. Conformational changes at the NBDs (the Pgp engines) lead to changes across Pgp transmembrane domains that result in substrate translocation. According to current alternating access models (substrate-binding pocket accessible only to one side of the membrane at a time), binding of ATP promotes NBD dimerization, resulting in external accessibility of the drug-binding site (outward-facing, closed NBD conformation), and ATP hydrolysis leads to dissociation of the NBDs with the subsequent return of the accessibility of the binding site to the cytoplasmic side (inward-facing, open NBD conformation). However, previous work has not investigated these events under near-physiological conditions in a lipid bilayer and in the presence of transport substrate. Here, we used luminescence resonance energy transfer (LRET) to measure the distances between the two Pgp NBDs. Pgp was labeled with LRET probes, reconstituted in lipid nanodiscs, and the distance between the NBDs was measured at 37 °C. In the presence of verapamil, a substrate that activates ATP hydrolysis, the NBDs of Pgp reconstituted in nanodiscs were never far apart during the hydrolysis cycle, and we never observed the NBD-NBD distances of tens of Å that have previously been reported. However, we found two main conformations that coexist in a dynamic equilibrium under all conditions studied. Our observations highlight the importance of performing studies of efflux pumps under near-physiological conditions, in a lipid bilayer, at 37 °C, and during substrate-stimulated hydrolysis.
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Affiliation(s)
- Maria E Zoghbi
- From the Department of Cell Physiology and Molecular Biophysics
| | - Leo Mok
- Department of Cell Biology and Biochemistry, and
| | | | | | | | - Ina L Urbatsch
- Department of Cell Biology and Biochemistry, and .,Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas 79430
| | - Guillermo A Altenberg
- From the Department of Cell Physiology and Molecular Biophysics, .,Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas 79430
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Zoghbi ME, Altenberg GA. Luminescence resonance energy transfer spectroscopy of ATP-binding cassette proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:854-867. [PMID: 28801111 DOI: 10.1016/j.bbamem.2017.08.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 07/31/2017] [Accepted: 08/01/2017] [Indexed: 12/11/2022]
Abstract
The ATP-binding cassette (ABC) superfamily includes regulatory and transport proteins. Most human ABC exporters pump substrates out of cells using energy from ATP hydrolysis. Although major advances have been made toward understanding the molecular mechanism of ABC exporters, there are still many issues unresolved. During the last few years, luminescence resonance energy transfer has been used to detect conformational changes in real time, with atomic resolution, in isolated ABC nucleotide binding domains (NBDs) and full-length ABC exporters. NBDs are particularly interesting because they provide the power stroke for substrate transport. Luminescence resonance energy transfer (LRET) is a spectroscopic technique that can provide dynamic information with atomic-resolution of protein conformational changes under physiological conditions. Using LRET, it has been shown that NBD dimerization, a critical step in ABC proteins catalytic cycle, requires binding of ATP to two nucleotide binding sites. However, hydrolysis at just one of the sites can drive dissociation of the NBD dimer. It was also found that the NBDs of the bacterial ABC exporter MsbA reconstituted in a lipid bilayer membrane and studied at 37°C never separate as much as suggested by crystal structures. This observation stresses the importance of performing structural/functional studies of ABC exporters under physiologic conditions. This article is part of a Special Issue entitled: Beyond the Structure-Function Horizon of Membrane Proteins edited by Ute Hellmich, Rupak Doshi and Benjamin McIlwain.
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Affiliation(s)
- Maria E Zoghbi
- School of Natural Sciences, University of California, Merced, 4225 N. Hospital Road, Atwater, CA, USA
| | - Guillermo A Altenberg
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79423-6551, USA.
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Chen B, Liu L, Ho H, Chen Y, Yang Z, Liang X, Payandeh J, Dean B, Hop CECA, Deng Y. Strategies of Drug Transporter Quantitation by LC-MS: Importance of Peptide Selection and Digestion Efficiency. AAPS JOURNAL 2017; 19:1469-1478. [PMID: 28589509 DOI: 10.1208/s12248-017-0106-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 05/24/2017] [Indexed: 12/18/2022]
Abstract
Huge variation of drug transporter abundance was seen in the literature, making PBPK prediction difficult when transporters play a major role. Among multiple factors such as membrane fraction, digestion, and peptide selection that contributed to such variation, peptide selection is the least discussed. Herein, a strategy was established by using a small amount of purified protein standard to select a peptide with near 100% digestion efficiency for quantitation of a transporter protein MDR1. The impact of native membrane protein's tertiary structure on the digestion efficiency of surrogate peptides of MDR1 was investigated. Peptides in more solvent accessible regions are found to be digested much more efficiently than those in large stretches of helical structures. The concentration of peptide EALDESIPPVSFWR(EAL) in the most solvent accessible linker region of MDR1 was found closest to the true protein concentration. When using EAL for MDR1 quantitation, the abundance is over 10 times higher than previously reported, indicating the importance of peptide selection for transporter quantitation. In addition, this study also proposes a screening strategy to select peptides appropriate for relative quantitation for in vitro-in vivo extrapolation in the absence of any protein standard.
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Affiliation(s)
- Buyun Chen
- Genentech Inc, 1 DNA Way, South San Francisco, California, 94080, USA.
| | - Liling Liu
- Genentech Inc, 1 DNA Way, South San Francisco, California, 94080, USA
| | - Hoangdung Ho
- Genentech Inc, 1 DNA Way, South San Francisco, California, 94080, USA
| | - Yuan Chen
- Genentech Inc, 1 DNA Way, South San Francisco, California, 94080, USA
| | - Ze Yang
- Stanford University, 450 Serra Mall, Stanford, California, 94305, USA
| | - Xiaorong Liang
- Genentech Inc, 1 DNA Way, South San Francisco, California, 94080, USA
| | - Jian Payandeh
- Genentech Inc, 1 DNA Way, South San Francisco, California, 94080, USA
| | - Brian Dean
- Genentech Inc, 1 DNA Way, South San Francisco, California, 94080, USA
| | | | - Yuzhong Deng
- Genentech Inc, 1 DNA Way, South San Francisco, California, 94080, USA
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Fosso-Tande J, Black C, G. Aller S, Lu L, D. Hills Jr R. Simulation of lipid-protein interactions with the CgProt force field. AIMS MOLECULAR SCIENCE 2017. [DOI: 10.3934/molsci.2017.3.352] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Furuta T, Sato Y, Sakurai M. Structural Dynamics of the Heterodimeric ABC Transporter TM287/288 Induced by ATP and Substrate Binding. Biochemistry 2016; 55:6730-6738. [PMID: 27933796 DOI: 10.1021/acs.biochem.6b00947] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
TM287/288 is a heterodimeric ATP-binding cassette (ABC) transporter, which harnesses the energy of ATP binding and hydrolysis at the nucleotide-binding domains (NBDs) to transport a wide variety of molecules through the transmembrane domains (TMDs) by alternating inward- and outward-facing conformations. Here, we conducted multiple 100 ns molecular dynamics simulations of TM287/288 in different ATP- and substrate-bound states to elucidate the effects of ATP and substrate binding. As a result, the binding of two ATP molecules to the NBDs induced the formation of the consensus ATP-binding pocket (ABP2) or the NBD dimerization, whereas these processes did not occur in the presence of a single ATP molecule or when the protein was in its apo state. Moreover, binding of the substrate to the TMDs enhanced the formation of ABP2 through allosteric TMD-NBD communication. Furthermore, in the apo state, α-helical subdomains of the NBDs approached each other, acquiring a conformation with core half-pockets exposed to the solvent, appropriate for ATP binding. We propose a "core-exposed" model for this novel conformation found in the apo state of ABC transporters. These findings provide important insights into the structural dynamics of ABC transporters.
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Affiliation(s)
- Tadaomi Furuta
- Center for Biological Resources and Informatics, Tokyo Institute of Technology , B-62 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan
| | - Yukiko Sato
- Center for Biological Resources and Informatics, Tokyo Institute of Technology , B-62 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan
| | - Minoru Sakurai
- Center for Biological Resources and Informatics, Tokyo Institute of Technology , B-62 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan
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Abstract
P-glycoprotein (P-gp) is an ATP-binding cassette transporter that exports a huge range of compounds out of cells and is thus one of the key proteins in conferring multi-drug resistance in cancer. Understanding how it achieves such a broad specificity and the series of conformational changes that allow export to occur form major, on-going, research objectives around the world. Much of our knowledge to date has been derived from mutagenesis and assay data. However, in recent years, there has also been great progress in structural biology and although the structure of human P-gp has not yet been solved, there are now a handful of related structures on which homology models can be built to aid in the interpretation of the vast amount of experimental data that currently exists. Many models for P-gp have been built with this aim, but the situation is complicated by the apparent flexibility of the system and by the fact that although many potential templates exist, there is large variation in the conformational state in which they have been crystallized. In this review, we summarize how homology modelling has been used in the past, how models are typically selected and finally illustrate how MD simulations can be used as a means to give more confidence about models that have been generated via this approach.
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