101
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Horáková E, Changmai P, Paris Z, Salmon D, Lukeš J. Simultaneous depletion of Atm and Mdl rebalances cytosolic Fe-S cluster assembly but not heme import into the mitochondrion ofTrypanosoma brucei. FEBS J 2015; 282:4157-75. [DOI: 10.1111/febs.13411] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 07/24/2015] [Accepted: 08/10/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Eva Horáková
- Biology Centre; Institute of Parasitology; Czech Academy of Sciences; České Budějovice (Budweis) Czech Republic
| | - Piya Changmai
- Biology Centre; Institute of Parasitology; Czech Academy of Sciences; České Budějovice (Budweis) Czech Republic
- Faculty of Sciences; University of South Bohemia; České Budějovice (Budweis) Czech Republic
| | - Zdeněk Paris
- Biology Centre; Institute of Parasitology; Czech Academy of Sciences; České Budějovice (Budweis) Czech Republic
| | - Didier Salmon
- Institute of Medical Biochemistry Leopoldo de Meis; Centro de Ciências e da Saude; Federal University of Rio de Janeiro; Brazil
| | - Julius Lukeš
- Biology Centre; Institute of Parasitology; Czech Academy of Sciences; České Budějovice (Budweis) Czech Republic
- Faculty of Sciences; University of South Bohemia; České Budějovice (Budweis) Czech Republic
- Canadian Institute for Advanced Research; Toronto Ontario Canada
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102
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Bao H, Dalal K, Cytrynbaum E, Duong F. Sequential Action of MalE and Maltose Allows Coupling ATP Hydrolysis to Translocation in the MalFGK2 Transporter. J Biol Chem 2015; 290:25452-60. [PMID: 26338707 DOI: 10.1074/jbc.m115.671826] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Indexed: 01/05/2023] Open
Abstract
ATP-binding cassette (ABC) transporters have evolved an ATP-dependent alternating-access mechanism to transport substrates across membranes. Despite important progress, especially in their structural analysis, it is still unknown how the substrate stimulates ATP hydrolysis, the hallmark of ABC transporters. In this study, we measure the ATP turnover cycle of MalFGK2 in steady and pre-steady state conditions. We show that (i) the basal ATPase activity of MalFGK2 is very low because the cleavage of ATP is rate-limiting, (ii) the binding of open-state MalE to the transporter induces ATP cleavage but leaves release of Pi limiting, and (iii) the additional presence of maltose stimulates release of Pi, and therefore increases the overall ATP turnover cycle. We conclude that open-state MalE stabilizes MalFGK2 in the outward-facing conformation until maltose triggers return to the inward-facing state for substrate and Pi release. This concerted action explains why ATPase activity of MalFGK2 depends on maltose, and why MalE is essential for transport.
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Affiliation(s)
- Huan Bao
- From the Departments of Biochemistry and Molecular Biology and
| | - Kush Dalal
- From the Departments of Biochemistry and Molecular Biology and
| | - Eric Cytrynbaum
- Mathematics, University of British Columbia, Vancouver, British Columbia V6T1Z3, Canada
| | - Franck Duong
- From the Departments of Biochemistry and Molecular Biology and
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103
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Geng J, Pogozheva ID, Mosberg HI, Raghavan M. Use of Functional Polymorphisms To Elucidate the Peptide Binding Site of TAP Complexes. THE JOURNAL OF IMMUNOLOGY 2015; 195:3436-48. [PMID: 26324772 DOI: 10.4049/jimmunol.1500985] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 07/29/2015] [Indexed: 11/19/2022]
Abstract
TAP1/TAP2 complexes translocate peptides from the cytosol to the endoplasmic reticulum lumen to enable immune surveillance by CD8(+) T cells. Peptide transport is preceded by peptide binding to a cytosol-accessible surface of TAP1/TAP2 complexes, but the location of the TAP peptide-binding pocket remains unknown. Guided by the known contributions of polymorphic TAP variants to peptide selection, we combined homology modeling of TAP with experimental measurements to identify several TAP residues that interact with peptides. Models for peptide-TAP complexes were generated, which indicate bent conformation for peptides. The peptide binding site of TAP is located at the hydrophobic boundary of the cytosolic membrane leaflet, with striking parallels to the glutathione binding site of NaAtm1, a transporter that functions in bacterial heavy metal detoxification. These studies illustrate the conservation of the ligand recognition modes of bacterial and mammalians transporters involved in peptide-guided cellular surveillance.
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Affiliation(s)
- Jie Geng
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109; and
| | - Irina D Pogozheva
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Henry I Mosberg
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Malini Raghavan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109; and
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104
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Perez C, Gerber S, Boilevin J, Bucher M, Darbre T, Aebi M, Reymond JL, Locher KP. Structure and mechanism of an active lipid-linked oligosaccharide flippase. Nature 2015; 524:433-8. [PMID: 26266984 DOI: 10.1038/nature14953] [Citation(s) in RCA: 164] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 07/15/2015] [Indexed: 02/06/2023]
Abstract
The flipping of membrane-embedded lipids containing large, polar head groups is slow and energetically unfavourable, and is therefore catalysed by flippases, the mechanisms of which are unknown. A prominent example of a flipping reaction is the translocation of lipid-linked oligosaccharides that serve as donors in N-linked protein glycosylation. In Campylobacter jejuni, this process is catalysed by the ABC transporter PglK. Here we present a mechanism of PglK-catalysed lipid-linked oligosaccharide flipping based on crystal structures in distinct states, a newly devised in vitro flipping assay, and in vivo studies. PglK can adopt inward- and outward-facing conformations in vitro, but only outward-facing states are required for flipping. While the pyrophosphate-oligosaccharide head group of lipid-linked oligosaccharides enters the translocation cavity and interacts with positively charged side chains, the lipidic polyprenyl tail binds and activates the transporter but remains exposed to the lipid bilayer during the reaction. The proposed mechanism is distinct from the classical alternating-access model applied to other transporters.
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Affiliation(s)
- Camilo Perez
- Institute of Molecular Biology and Biophysics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Sabina Gerber
- Institute of Molecular Biology and Biophysics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Jérémy Boilevin
- Department of Chemistry and Biochemistry, University of Berne, CH-3012 Berne, Switzerland
| | - Monika Bucher
- Institute of Molecular Biology and Biophysics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Tamis Darbre
- Department of Chemistry and Biochemistry, University of Berne, CH-3012 Berne, Switzerland
| | - Markus Aebi
- Institute of Microbiology, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Jean-Louis Reymond
- Department of Chemistry and Biochemistry, University of Berne, CH-3012 Berne, Switzerland
| | - Kaspar P Locher
- Institute of Molecular Biology and Biophysics, ETH Zürich, CH-8093 Zürich, Switzerland
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105
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Lill R, Dutkiewicz R, Freibert SA, Heidenreich T, Mascarenhas J, Netz DJ, Paul VD, Pierik AJ, Richter N, Stümpfig M, Srinivasan V, Stehling O, Mühlenhoff U. The role of mitochondria and the CIA machinery in the maturation of cytosolic and nuclear iron–sulfur proteins. Eur J Cell Biol 2015; 94:280-91. [DOI: 10.1016/j.ejcb.2015.05.002] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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106
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Couturier J, Przybyla-Toscano J, Roret T, Didierjean C, Rouhier N. The roles of glutaredoxins ligating Fe–S clusters: Sensing, transfer or repair functions? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1513-27. [DOI: 10.1016/j.bbamcr.2014.09.018] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 09/17/2014] [Accepted: 09/18/2014] [Indexed: 01/05/2023]
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107
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Subramanian N, Condic-Jurkic K, Mark AE, O'Mara ML. Identification of Possible Binding Sites for Morphine and Nicardipine on the Multidrug Transporter P-Glycoprotein Using Umbrella Sampling Techniques. J Chem Inf Model 2015; 55:1202-17. [PMID: 25938863 DOI: 10.1021/ci5007382] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The multidrug transporter P-glycoprotein (P-gp) is central to the development of multidrug resistance in cancer. While residues essential for transport and binding have been identified, the location, composition, and specificity of potential drug binding sites are uncertain. Here molecular dynamics simulations are used to calculate the free energy profile for the binding of morphine and nicardipine to P-gp. We show that morphine and nicardipine primarily interact with key residues implicated in binding and transport from mutational studies, binding at different but overlapping sites within the transmembrane pore. Their permeation pathways were distinct but involved overlapping sets of residues. The results indicate that the binding location and permeation pathways of morphine and nicardipine are not well separated and cannot be considered as unique. This has important implications for our understanding of substrate uptake and transport by P-gp. Our results are independent of the choice of starting structure and consistent with a range of experimental studies.
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Affiliation(s)
- Nandhitha Subramanian
- †School of Chemistry and Molecular Biosciences, §The Institute for Molecular Biosciences, and ‡School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia
| | - Karmen Condic-Jurkic
- †School of Chemistry and Molecular Biosciences, §The Institute for Molecular Biosciences, and ‡School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia
| | - Alan E Mark
- †School of Chemistry and Molecular Biosciences, §The Institute for Molecular Biosciences, and ‡School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia
| | - Megan L O'Mara
- †School of Chemistry and Molecular Biosciences, §The Institute for Molecular Biosciences, and ‡School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia
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108
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Bukowska MA, Hohl M, Geertsma ER, Hürlimann LM, Grütter MG, Seeger MA. A Transporter Motor Taken Apart: Flexibility in the Nucleotide Binding Domains of a Heterodimeric ABC Exporter. Biochemistry 2015; 54:3086-99. [PMID: 25947941 DOI: 10.1021/acs.biochem.5b00188] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
ABC exporters are ubiquitous multidomain transport proteins that couple ATP hydrolysis at a pair of nucleotide binding domains to substrate transport across the lipid bilayer mediated by two transmembrane domains. Recently, the crystal structure of the heterodimeric ABC exporter TM287/288 was determined. One of its asymmetric ATP binding sites is called the degenerate site; it binds nucleotides tightly but is impaired in terms of ATP hydrolysis. Here we report the crystal structures of both isolated motor domains of TM287/288. Unexpectedly, structural elements constituting the degenerate ATP binding site are disordered in these crystals and become structured only in the context of the full-length transporter. In addition, hydrogen bonding patterns of key residues, including those of the catalytically important Walker B and the switch loop motifs, are fundamentally different in the solitary NBDs compared to those in the intact transport protein. The structures reveal crucial interdomain contacts that need to be established for the proper assembly of the functional transporter complex.
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Affiliation(s)
- Magdalena A Bukowska
- †Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Michael Hohl
- †Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.,‡Institute of Medical Microbiology, University of Zurich, Gloriastrasse 30/32, 8006 Zurich, Switzerland
| | - Eric R Geertsma
- †Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Lea M Hürlimann
- †Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.,‡Institute of Medical Microbiology, University of Zurich, Gloriastrasse 30/32, 8006 Zurich, Switzerland
| | - Markus G Grütter
- †Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Markus A Seeger
- †Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.,‡Institute of Medical Microbiology, University of Zurich, Gloriastrasse 30/32, 8006 Zurich, Switzerland
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109
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Bundy JG, Kille P. Metabolites and metals in Metazoa--what role do phytochelatins play in animals? Metallomics 2015; 6:1576-82. [PMID: 24926533 DOI: 10.1039/c4mt00078a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Phytochelatins are sulfur-rich metal-binding peptides, and phytochelatin synthesis is one of the key mechanisms by which plants protect themselves against toxic soft metal ions such as cadmium. It has been known for a while now that some invertebrates also possess functional phytochelatin synthase (PCS) enzymes, and that at least one species, the nematode Caenorhabditis elegans, produces phytochelatins to help detoxify cadmium, and probably also other metal and metalloid ions including arsenic, zinc, selenium, silver, and copper. Here, we review recent studies on the occurrence, utilization, and regulation of phytochelatin synthesis in invertebrates. The phytochelatin synthase gene has a wide phylogenetic distribution, and can be found in species that cover almost all of the animal tree of life. The evidence to date, though, suggests that the occurrence is patchy, and even though some members of particular taxonomic groups may contain PCS genes, there are also many species without these genes. For animal species that do possess PCS genes, some of them (e.g. earthworms) do synthesize phytochelatins in response to potentially toxic elements, whereas others (e.g. Schistosoma mansoni, a parasitic helminth) do not appear to do so. Just how (and if) phytochelatins in invertebrates complement the function of metallothioneins remains to be elucidated, and the temporal, spatial, and metal specificity of the two systems is still unknown.
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Affiliation(s)
- J G Bundy
- Department of Surgery and Cancer, Imperial College London, Sir Alexander Fleming Building, London SW7 2AZ, UK.
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110
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Structural basis for substrate specificity of an amino acid ABC transporter. Proc Natl Acad Sci U S A 2015; 112:5243-8. [PMID: 25848002 DOI: 10.1073/pnas.1415037112] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
ATP-binding cassette (ABC) transporters are ubiquitous integral membrane proteins that translocate a variety of substrates, ranging from ions to macromolecules, either out of or into the cytosol (hence defined as importers or exporters, respectively). It has been demonstrated that ABC exporters and importers function through a common mechanism involving conformational switches between inward-facing and outward-facing states; however, the mechanism underlying their functions, particularly substrate recognition, remains elusive. Here we report the structures of an amino acid ABC importer Art(QN)2 from Thermoanaerobacter tengcongensis composed of homodimers each of the transmembrane domain ArtQ and the nucleotide-binding domain ArtN, either in its apo form or in complex with substrates (Arg, His) and/or ATPs. The structures reveal that the straddling of the TMDs around the twofold axis forms a substrate translocation pathway across the membrane. Interestingly, each TMD has a negatively charged pocket that together create a negatively charged internal tunnel allowing amino acids carrying positively charged groups to pass through. Our structural and functional studies provide a better understanding of how ABC transporters select and translocate their substrates.
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111
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Mornon JP, Hoffmann B, Jonic S, Lehn P, Callebaut I. Full-open and closed CFTR channels, with lateral tunnels from the cytoplasm and an alternative position of the F508 region, as revealed by molecular dynamics. Cell Mol Life Sci 2015; 72:1377-403. [PMID: 25287046 PMCID: PMC11113974 DOI: 10.1007/s00018-014-1749-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 09/28/2014] [Accepted: 09/29/2014] [Indexed: 12/17/2022]
Abstract
In absence of experimental 3D structures, several homology models, based on ABC exporter 3D structures, have provided significant insights into the molecular mechanisms underlying the function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, a chloride channel whose defects are associated with cystic fibrosis (CF). Until now, these models, however, did not furnished much insights into the continuous way that ions could follow from the cytosol to the extracellular milieu in the open form of the channel. Here, we have built a refined model of CFTR, based on the outward-facing Sav1866 experimental 3D structure and integrating the evolutionary and structural information available today. Molecular dynamics simulations revealed significant conformational changes, resulting in a full-open channel, accessible from the cytosol through lateral tunnels displayed in the long intracellular loops (ICLs). At the same time, the region of nucleotide-binding domain 1 in contact with one of the ICLs and carrying amino acid F508, the deletion of which is the most common CF-causing mutation, was found to adopt an alternative but stable position. Then, in a second step, this first stable full-open conformation evolved toward another stable state, in which only a limited displacement of the upper part of the transmembrane helices leads to a closure of the channel, in a conformation very close to that adopted by the Atm1 ABC exporter, in an inward-facing conformation. These models, supported by experimental data, provide significant new insights into the CFTR structure-function relationships and into the possible impact of CF-causing mutations.
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Affiliation(s)
- Jean-Paul Mornon
- IMPMC, Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 7590, Museum National d’Histoire Naturelle, IRD UMR 206, IUC, Case 115, 4 Place Jussieu, 75005 Paris Cedex 05, France
| | - Brice Hoffmann
- IMPMC, Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 7590, Museum National d’Histoire Naturelle, IRD UMR 206, IUC, Case 115, 4 Place Jussieu, 75005 Paris Cedex 05, France
| | - Slavica Jonic
- IMPMC, Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 7590, Museum National d’Histoire Naturelle, IRD UMR 206, IUC, Case 115, 4 Place Jussieu, 75005 Paris Cedex 05, France
| | - Pierre Lehn
- INSERM U1078, SFR ScInBioS, Université de Bretagne Occidentale, Brest, France
| | - Isabelle Callebaut
- IMPMC, Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 7590, Museum National d’Histoire Naturelle, IRD UMR 206, IUC, Case 115, 4 Place Jussieu, 75005 Paris Cedex 05, France
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112
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Antigen Translocation Machineries in Adaptive Immunity and Viral Immune Evasion. J Mol Biol 2015; 427:1102-18. [DOI: 10.1016/j.jmb.2014.09.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 09/04/2014] [Accepted: 09/05/2014] [Indexed: 11/23/2022]
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113
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Li J, Cowan JA. Glutathione-coordinated [2Fe-2S] cluster: a viable physiological substrate for mitochondrial ABCB7 transport. Chem Commun (Camb) 2015; 51:2253-5. [PMID: 25556595 PMCID: PMC4522903 DOI: 10.1039/c4cc09175b] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The glutathione-coordinated [2Fe-2S] cluster is demonstrated to be a viable and likely substrate for physiological iron-sulfur cluster transport by Atm1p, a mitochondrial ABC export protein. Flow cytometry and colorimetric assays demonstrate a quantitative methodology for study of metal translocation proteins and their proteoliposome products.
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Affiliation(s)
- Jingwei Li
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Ave, Columbus, OH 43210, USA.
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114
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Moeller A, Lee SC, Tao H, Speir JA, Chang G, Urbatsch IL, Potter CS, Carragher B, Zhang Q. Distinct conformational spectrum of homologous multidrug ABC transporters. Structure 2015; 23:450-460. [PMID: 25661651 DOI: 10.1016/j.str.2014.12.013] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 11/25/2014] [Accepted: 12/12/2014] [Indexed: 01/10/2023]
Abstract
ATP-binding cassette (ABC) exporters are ubiquitously found in all kingdoms of life and their members play significant roles in mediating drug pharmacokinetics and multidrug resistance in the clinic. Significant questions and controversies remain regarding the relevance of their conformations observed in X-ray structures, their structural dynamics, and mechanism of transport. Here, we used single particle electron microscopy (EM) to delineate the entire conformational spectrum of two homologous ABC exporters (bacterial MsbA and mammalian P-glycoprotein) and the influence of nucleotide and substrate binding. Newly developed amphiphiles in complex with lipids that support high protein stability and activity enabled EM visualization of individual complexes in a membrane-mimicking environment. The data provide a comprehensive view of the conformational flexibility of these ABC exporters under various states and demonstrate not only similarities but striking differences between their mechanistic and energetic regulation of conformational changes.
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Affiliation(s)
- Arne Moeller
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; The National Resource for Automated Molecular Microscopy, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Sung Chang Lee
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Houchao Tao
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jeffrey A Speir
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; The National Resource for Automated Molecular Microscopy, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Geoffrey Chang
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Ina L Urbatsch
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
| | - Clinton S Potter
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; The National Resource for Automated Molecular Microscopy, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Bridget Carragher
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; The National Resource for Automated Molecular Microscopy, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Qinghai Zhang
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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115
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Single liposome analysis of peptide translocation by the ABC transporter TAPL. Proc Natl Acad Sci U S A 2015; 112:2046-51. [PMID: 25646430 DOI: 10.1073/pnas.1418100112] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
ATP-binding cassette (ABC) transporters use ATP to drive solute transport across biological membranes. Members of this superfamily have crucial roles in cell physiology, and some of the transporters are linked to severe diseases. However, understanding of the transport mechanism, especially of human ABC exporters, is scarce. We reconstituted the human lysosomal polypeptide ABC transporter TAPL, expressed in Pichia pastoris, into lipid vesicles (liposomes) and performed explicit transport measurements. We analyzed solute transport at the single liposome level by monitoring the coincident fluorescence of solutes and proteoliposomes in the focal volume of a confocal microscope. We determined a turnover number of eight peptides per minute, which is two orders of magnitude higher than previously estimated from macroscopic measurements. Moreover, we show that TAPL translocates peptides against a large concentration gradient. Maximal filling is not limited by an electrochemical gradient but by trans-inhibition. Countertransport and reversibility studies demonstrate that peptide translocation is a strictly unidirectional process. Altogether, these data are included in a refined model of solute transport by ABC exporters.
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116
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Wang Z, Liao JL. Probing Structural Determinants of ATP-Binding Cassette Exporter Conformational Transition Using Coarse-Grained Molecular Dynamics. J Phys Chem B 2015; 119:1295-301. [DOI: 10.1021/jp509178k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Zi Wang
- Department of Chemical Physics, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui Province, People’s Republic of China, 230026
| | - Jie-Lou Liao
- Department of Chemical Physics, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui Province, People’s Republic of China, 230026
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117
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Paul VD, Lill R. Biogenesis of cytosolic and nuclear iron-sulfur proteins and their role in genome stability. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1528-39. [PMID: 25583461 DOI: 10.1016/j.bbamcr.2014.12.018] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 12/08/2014] [Accepted: 12/12/2014] [Indexed: 01/09/2023]
Abstract
Iron-sulfur (Fe-S) clusters are versatile protein cofactors that require numerous components for their synthesis and insertion into apoproteins. In eukaryotes, maturation of cytosolic and nuclear Fe-S proteins is accomplished by cooperation of the mitochondrial iron-sulfur cluster (ISC) assembly and export machineries, and the cytosolic iron-sulfur protein assembly (CIA) system. Currently, nine CIA proteins are known to specifically assist the two major steps of the biogenesis reaction. They are essential for cell viability and conserved from yeast to man. The essential character of this biosynthetic process is explained by the involvement of Fe-S proteins in central processes of life, e.g., protein translation and numerous steps of nuclear DNA metabolism such as DNA replication and repair. Malfunctioning of these latter Fe-S enzymes leads to genome instability, a hallmark of cancer. This review is focused on the maturation and biological function of cytosolic and nuclear Fe-S proteins, a topic of central interest for both basic and medical research. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
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Affiliation(s)
- Viktoria Désirée Paul
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, Robert-Koch-Straße 6, 35032 Marburg, Germany
| | - Roland Lill
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, Robert-Koch-Straße 6, 35032 Marburg, Germany; LOEWE Zentrum für Synthetische Mikrobiologie SynMikro, Hans-Meerwein-Str., 35043 Marburg, Germany.
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118
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Chufan EE, Sim HM, Ambudkar SV. Molecular basis of the polyspecificity of P-glycoprotein (ABCB1): recent biochemical and structural studies. Adv Cancer Res 2015; 125:71-96. [PMID: 25640267 DOI: 10.1016/bs.acr.2014.10.003] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
ABCB1 (P-glycoprotein/P-gp) is an ATP-binding cassette transporter well known for its association with multidrug resistance in cancer cells. Powered by the hydrolysis of ATP, it effluxes structurally diverse compounds. In this chapter, we discuss current views on the molecular basis of the substrate polyspecificity of P-gp. One of the features that accounts for this property is the structural flexibility observed in P-gp. Several X-ray crystal structures of mouse P-gp have been published recently in the absence of nucleotide, with and without bound inhibitors. All the structures are in an inward-facing conformation exhibiting different degrees of domain separation, thus revealing a highly flexible protein. Biochemical and biophysical studies also demonstrate this flexibility in mouse as well as human P-gp. Site-directed mutagenesis has revealed the existence of multiple transport-active binding sites in P-gp for a single substrate. Thus, drugs can bind at either primary or secondary sites. Biochemical, molecular modeling, and structure-activity relationship studies suggest a large, common drug-binding pocket with overlapping sites for different substrates. We propose that in addition to the structural flexibility, the molecular or chemical flexibility also contributes to the binding of substrates to multiple sites forming the basis of polyspecificity.
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Affiliation(s)
- Eduardo E Chufan
- Center for Cancer Research, Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Hong-May Sim
- Center for Cancer Research, Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Suresh V Ambudkar
- Center for Cancer Research, Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
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119
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Sun J, Zhou J, Wang Z, He W, Zhang D, Tong Q, Su X. Multi-omics based changes in response to cadmium toxicity in Bacillus licheniformis A. RSC Adv 2015. [DOI: 10.1039/c4ra15280h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cadmium (Cd), a widespread substance with high toxicity and persistence, is known to cause a broad range of adverse effects in all living organisms.
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Affiliation(s)
- Jing Sun
- School of Marine Sciences
- Ningbo University
- Ningbo 315211
- China
- College of Food Science and Technology
| | - Jun Zhou
- School of Marine Sciences
- Ningbo University
- Ningbo 315211
- China
| | - Zhonghua Wang
- School of Marine Sciences
- Ningbo University
- Ningbo 315211
- China
| | - Weina He
- School of Marine Sciences
- Ningbo University
- Ningbo 315211
- China
| | - Dijun Zhang
- School of Marine Sciences
- Ningbo University
- Ningbo 315211
- China
| | - Qianqian Tong
- School of Marine Sciences
- Ningbo University
- Ningbo 315211
- China
| | - Xiurong Su
- School of Marine Sciences
- Ningbo University
- Ningbo 315211
- China
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120
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Fang SC, Chung CL, Chen CH, Lopez-Paz C, Umen JG. Defects in a new class of sulfate/anion transporter link sulfur acclimation responses to intracellular glutathione levels and cell cycle control. PLANT PHYSIOLOGY 2014; 166:1852-68. [PMID: 25361960 PMCID: PMC4256884 DOI: 10.1104/pp.114.251009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 10/29/2014] [Indexed: 05/18/2023]
Abstract
We previously identified a mutation, suppressor of mating type locus3 15-1 (smt15-1), that partially suppresses the cell cycle defects caused by loss of the retinoblastoma tumor suppressor-related protein encoded by the MAT3 gene in Chlamydomonas reinhardtii. smt15-1 single mutants were also found to have a cell cycle defect leading to a small-cell phenotype. SMT15 belongs to a previously uncharacterized subfamily of putative membrane-localized sulfate/anion transporters that contain a sulfate transporter domain and are found in a widely distributed subset of eukaryotes and bacteria. Although we observed that smt15-1 has a defect in acclimation to sulfur-limited growth conditions, sulfur acclimation (sac) mutants, which are more severely defective for acclimation to sulfur limitation, do not have cell cycle defects and cannot suppress mat3. Moreover, we found that smt15-1, but not sac mutants, overaccumulates glutathione. In wild-type cells, glutathione fluctuated during the cell cycle, with highest levels in mid G1 phase and lower levels during S and M phases, while in smt15-1, glutathione levels remained elevated during S and M. In addition to increased total glutathione levels, smt15-1 cells had an increased reduced-to-oxidized glutathione redox ratio throughout the cell cycle. These data suggest a role for SMT15 in maintaining glutathione homeostasis that impacts the cell cycle and sulfur acclimation responses.
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Affiliation(s)
- Su-Chiung Fang
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan County 741, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Institute of Marine Biotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (C.-L.C.); andDonald Danforth Plant Science Center, St. Louis, Missouri 63132 (C.L.-P., J.G.U.)
| | - Chin-Lin Chung
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan County 741, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Institute of Marine Biotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (C.-L.C.); andDonald Danforth Plant Science Center, St. Louis, Missouri 63132 (C.L.-P., J.G.U.)
| | - Chun-Han Chen
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan County 741, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Institute of Marine Biotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (C.-L.C.); andDonald Danforth Plant Science Center, St. Louis, Missouri 63132 (C.L.-P., J.G.U.)
| | - Cristina Lopez-Paz
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan County 741, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Institute of Marine Biotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (C.-L.C.); andDonald Danforth Plant Science Center, St. Louis, Missouri 63132 (C.L.-P., J.G.U.)
| | - James G Umen
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan County 741, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Institute of Marine Biotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (C.-L.C.); andDonald Danforth Plant Science Center, St. Louis, Missouri 63132 (C.L.-P., J.G.U.)
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121
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Mammalian iron-sulphur proteins: novel insights into biogenesis and function. Nat Rev Mol Cell Biol 2014; 16:45-55. [PMID: 25425402 DOI: 10.1038/nrm3909] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Iron-sulphur (Fe-S) clusters are inorganic cofactors that are found in nearly all species and are composed of various combinations of iron and sulphur atoms. Fe-S clusters can accept or donate single electrons to carry out oxidation and reduction reactions and to facilitate electron transport. Many details of how these complex modular structures are assembled and ligated to cellular proteins in the mitochondrial, nuclear and cytosolic compartments of mammalian cells remain unclear. Recent evidence indicates that a Leu-Tyr-Arg (LYR) tripeptide motif found in some Fe-S recipient proteins may facilitate the direct and shielded transfer of Fe-S clusters from a scaffold to client proteins. Fe-S clusters are probably an unrecognized and elusive cofactor of many known proteins.
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122
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Subnanometre-resolution electron cryomicroscopy structure of a heterodimeric ABC exporter. Nature 2014; 517:396-400. [PMID: 25363761 DOI: 10.1038/nature13872] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 09/17/2014] [Indexed: 02/07/2023]
Abstract
ATP-binding cassette (ABC) transporters translocate substrates across cell membranes, using energy harnessed from ATP binding and hydrolysis at their nucleotide-binding domains. ABC exporters are present both in prokaryotes and eukaryotes, with examples implicated in multidrug resistance of pathogens and cancer cells, as well as in many human diseases. TmrAB is a heterodimeric ABC exporter from the thermophilic Gram-negative eubacterium Thermus thermophilus; it is homologous to various multidrug transporters and contains one degenerate site with a non-catalytic residue next to the Walker B motif. Here we report a subnanometre-resolution structure of detergent-solubilized TmrAB in a nucleotide-free, inward-facing conformation by single-particle electron cryomicroscopy. The reconstructions clearly resolve characteristic features of ABC transporters, including helices in the transmembrane domain and nucleotide-binding domains. A cavity in the transmembrane domain is accessible laterally from the cytoplasmic side of the membrane as well as from the cytoplasm, indicating that the transporter lies in an inward-facing open conformation. The two nucleotide-binding domains remain in contact via their carboxy-terminal helices. Furthermore, comparison between our structure and the crystal structures of other ABC transporters suggests a possible trajectory of conformational changes that involves a sliding and rotating motion between the two nucleotide-binding domains during the transition from the inward-facing to outward-facing conformations.
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123
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Léger T, Garcia C, Ounissi M, Lelandais G, Camadro JM. The metacaspase (Mca1p) has a dual role in farnesol-induced apoptosis in Candida albicans. Mol Cell Proteomics 2014; 14:93-108. [PMID: 25348831 DOI: 10.1074/mcp.m114.041210] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Manipulating the apoptotic response of Candida albicans may help in the control of this opportunistic pathogen. The metacaspase Mca1p has been described as a key protease for apoptosis in C. albicans but little is known about its cleavage specificity and substrates. We therefore initiated a series of studies to describe its function. We used a strain disrupted for the MCA1 gene (mca1Δ/Δ) and compared its proteome to that of a wild-type isogenic strain, in the presence and absence of a known inducer of apoptosis, the quorum-sensing molecule farnesol. Label-free and TMT labeling quantitative proteomic analyses showed that both mca1 disruption and farnesol treatment significantly affected the proteome of the cells. The combination of both conditions led to an unexpected biological response: the strong overexpression of proteins implicated in the general stress. We studied sites cleaved by Mca1p using native peptidomic techniques, and a bottom-up approach involving GluC endoprotease: there appeared to be a "K/R" substrate specificity in P1 and a "D/E" specificity in P2. We also found 77 potential substrates of Mca1p, 13 of which validated using the most stringent filters, implicated in protein folding, protein aggregate resolubilization, glycolysis, and a number of mitochondrial functions. An immunoblot assay confirmed the cleavage of Ssb1p, a member of the HSP70 family of heat-shock proteins, in conditions where the metacaspase is activated. These various results indicate that Mca1p is involved in a limited and specific proteolysis program triggered by apoptosis. One of the main functions of Mca1p appears to be the degradation of several major heat-shock proteins, thereby contributing to weakening cellular defenses and amplifying the cell death process. Finally, Mca1p appears to contribute significantly to the control of mitochondria biogenesis and degradation. Consequently, Mca1p may be a link between the extrinsic and the intrinsic programmed cell death pathways in C. albicans.
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Affiliation(s)
- Thibaut Léger
- From the ‡Mass spectrometry Laboratory, Institut Jacques Monod, UMR 7592, Univ Paris Diderot, CNRS, Sorbonne Paris Cité, F-75205 Paris, France
| | - Camille Garcia
- From the ‡Mass spectrometry Laboratory, Institut Jacques Monod, UMR 7592, Univ Paris Diderot, CNRS, Sorbonne Paris Cité, F-75205 Paris, France
| | - Marwa Ounissi
- From the ‡Mass spectrometry Laboratory, Institut Jacques Monod, UMR 7592, Univ Paris Diderot, CNRS, Sorbonne Paris Cité, F-75205 Paris, France
| | - Gaëlle Lelandais
- §Mitochondria, Metals and Oxidative Stress group, Institut Jacques Monod, UMR 7592, Univ Paris Diderot, CNRS, Sorbonne Paris Cité, F-75205 Paris, France
| | - Jean-Michel Camadro
- From the ‡Mass spectrometry Laboratory, Institut Jacques Monod, UMR 7592, Univ Paris Diderot, CNRS, Sorbonne Paris Cité, F-75205 Paris, France; §Mitochondria, Metals and Oxidative Stress group, Institut Jacques Monod, UMR 7592, Univ Paris Diderot, CNRS, Sorbonne Paris Cité, F-75205 Paris, France
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Majorel C, Hannibal L, Ducousso M, Lebrun M, Jourand P. Evidence of nickel (Ni) efflux in Ni-tolerant ectomycorhizal Pisolithus albus isolated from ultramafic soil. ENVIRONMENTAL MICROBIOLOGY REPORTS 2014; 6:510-8. [PMID: 25646544 DOI: 10.1111/1758-2229.12176] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Nickel (Ni)-tolerant ectomycorrhizal Pisolithus albus was isolated from extreme ultramafic soils that are naturally rich in heavy metals. This study aimed to identify the specific molecular mechanisms associated with the response of P. albus to nickel. In presence of high concentration of nickel, P. albus Ni-tolerant isolate showed a low basal accumulation of nickel in its fungal tissues and was able to perform a metal efflux mechanism. Three genes putatively involved in metal efflux were identified from the P. albus transcriptome, and their overexpression was confirmed in the mycelium that was cultivated in vitro in the presence of nickel and in fungal tissues that were sampled in situ. Cloning these genes in yeast provided significant advantages in terms of nickel tolerance (+ 31% Ni EC50) and growth (+ 83% μ) compared with controls. Furthermore, nickel efflux was also detected in the transformed yeast cells. Protein sequence analysis indicated that the genes encoded a P-type-ATPase, an ABC transporter and a major facilitator superfamily permease (MFS). This study sheds light on a global mechanism of metal efflux by P. albus cells that supports nickel tolerance. These specific responses to nickel might contribute to the fungal adaptation in ultramafic soil.
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125
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Wang K, Sitsel O, Meloni G, Autzen HE, Andersson M, Klymchuk T, Nielsen AM, Rees DC, Nissen P, Gourdon P. Structure and mechanism of Zn2+-transporting P-type ATPases. Nature 2014; 514:518-22. [PMID: 25132545 PMCID: PMC4259247 DOI: 10.1038/nature13618] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 06/25/2014] [Indexed: 12/23/2022]
Abstract
Zinc is an essential micronutrient for all living organisms. It is required for signalling and proper functioning of a range of proteins involved in, for example, DNA binding and enzymatic catalysis. In prokaryotes and photosynthetic eukaryotes, Zn(2+)-transporting P-type ATPases of class IB (ZntA) are crucial for cellular redistribution and detoxification of Zn(2+) and related elements. Here we present crystal structures representing the phosphoenzyme ground state (E2P) and a dephosphorylation intermediate (E2·Pi) of ZntA from Shigella sonnei, determined at 3.2 Å and 2.7 Å resolution, respectively. The structures reveal a similar fold to Cu(+)-ATPases, with an amphipathic helix at the membrane interface. A conserved electronegative funnel connects this region to the intramembranous high-affinity ion-binding site and may promote specific uptake of cellular Zn(2+) ions by the transporter. The E2P structure displays a wide extracellular release pathway reaching the invariant residues at the high-affinity site, including C392, C394 and D714. The pathway closes in the E2·Pi state, in which D714 interacts with the conserved residue K693, which possibly stimulates Zn(2+) release as a built-in counter ion, as has been proposed for H(+)-ATPases. Indeed, transport studies in liposomes provide experimental support for ZntA activity without counter transport. These findings suggest a mechanistic link between PIB-type Zn(2+)-ATPases and PIII-type H(+)-ATPases and at the same time show structural features of the extracellular release pathway that resemble PII-type ATPases such as the sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase (SERCA) and Na(+), K(+)-ATPase. These findings considerably increase our understanding of zinc transport in cells and represent new possibilities for biotechnology and biomedicine.
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Affiliation(s)
- Kaituo Wang
- 1] Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark [2] Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark (K.W. and P.G.); Department of Experimental Medical Science, Lund University, Sölvegatan 19, SE-221 84 Lund, Sweden (P.G.). [3]
| | - Oleg Sitsel
- 1] Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark [2]
| | - Gabriele Meloni
- Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark
| | - Henriette Elisabeth Autzen
- Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark
| | - Magnus Andersson
- Science for Life Laboratory, Department of Theoretical Physics, Swedish e-Science Research Center, KTH Royal Institute of Technology, SE-171 21 Solna, Sweden
| | - Tetyana Klymchuk
- Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark
| | - Anna Marie Nielsen
- Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark
| | - Douglas C Rees
- Division of Chemistry and Chemical Engineering and Howard Hughes Medical Institute, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA
| | - Poul Nissen
- Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark
| | - Pontus Gourdon
- 1] Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark [2] Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark (K.W. and P.G.); Department of Experimental Medical Science, Lund University, Sölvegatan 19, SE-221 84 Lund, Sweden (P.G.)
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Schaedler TA, Thornton JD, Kruse I, Schwarzländer M, Meyer AJ, van Veen HW, Balk J. A conserved mitochondrial ATP-binding cassette transporter exports glutathione polysulfide for cytosolic metal cofactor assembly. J Biol Chem 2014; 289:23264-74. [PMID: 25006243 PMCID: PMC4156053 DOI: 10.1074/jbc.m114.553438] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
An ATP-binding cassette transporter located in the inner mitochondrial membrane is involved in iron-sulfur cluster and molybdenum cofactor assembly in the cytosol, but the transported substrate is unknown. ATM3 (ABCB25) from Arabidopsis thaliana and its functional orthologue Atm1 from Saccharomyces cerevisiae were expressed in Lactococcus lactis and studied in inside-out membrane vesicles and in purified form. Both proteins selectively transported glutathione disulfide (GSSG) but not reduced glutathione in agreement with a 3-fold stimulation of ATPase activity by GSSG. By contrast, Fe2+ alone or in combination with glutathione did not stimulate ATPase activity. Arabidopsis atm3 mutants were hypersensitive to an inhibitor of glutathione biosynthesis and accumulated GSSG in the mitochondria. The growth phenotype of atm3-1 was strongly enhanced by depletion of the mitochondrion-localized, GSH-dependent persulfide oxygenase ETHE1, suggesting that the physiological substrate of ATM3 contains persulfide in addition to glutathione. Consistent with this idea, a transportomics approach using mass spectrometry showed that glutathione trisulfide (GS-S-SG) was transported by Atm1. We propose that mitochondria export glutathione polysulfide, containing glutathione and persulfide, for iron-sulfur cluster assembly in the cytosol.
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Affiliation(s)
- Theresia A Schaedler
- From the John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom, the Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - Jeremy D Thornton
- From the John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | - Inga Kruse
- From the John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom, the School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Markus Schwarzländer
- the Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | - Andreas J Meyer
- the Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | - Hendrik W van Veen
- the Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, United Kingdom, and
| | - Janneke Balk
- From the John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom, the School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
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ABC transporters in adaptive immunity. Biochim Biophys Acta Gen Subj 2014; 1850:449-60. [PMID: 24923865 DOI: 10.1016/j.bbagen.2014.05.022] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Revised: 05/24/2014] [Accepted: 05/29/2014] [Indexed: 12/12/2022]
Abstract
BACKGROUND ABC transporters ubiquitously found in all kingdoms of life move a broad range of solutes across membranes. Crystal structures of four distinct types of ABC transport systems have been solved, shedding light on different conformational states within the transport process. Briefly, ATP-dependent flipping between inward- and outward-facing conformations allows directional transport of various solutes. SCOPE OF REVIEW The heterodimeric transporter associated with antigen processing TAP1/2 (ABCB2/3) is a crucial element of the adaptive immune system. The ABC transport complex shuttles proteasomal degradation products into the endoplasmic reticulum. These antigenic peptides are loaded onto major histocompatibility complex class I molecules and presented on the cell surface. We detail the functional modules of TAP, its ATPase and transport cycle, and its interaction with and modulation by other cellular components. In particular, we emphasize how viral factors inhibit TAP activity and thereby prevent detection of the infected host cell by cytotoxic T-cells. MAJOR CONCLUSIONS Merging functional details on TAP with structural insights from related ABC transporters refines the understanding of solute transport. Although human ABC transporters are extremely diverse, they still may employ conceptually related transport mechanisms. Appropriately, we delineate a working model of the transport cycle and how viral factors arrest TAP in distinct conformations. GENERAL SIGNIFICANCE Deciphering the transport cycle of human ABC proteins is the major issue in the field. The defined peptidic substrate, various inhibitory viral factors, and its role in adaptive immunity provide unique tools for the investigation of TAP, making it an ideal model system for ABC transporters in general. This article is part of a Special Issue entitled Structural biochemistry and biophysics of membrane proteins.
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128
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Srinivasan V, Pierik AJ, Lill R. Crystal structures of nucleotide-free and glutathione-bound mitochondrial ABC transporter Atm1. Science 2014; 343:1137-40. [PMID: 24604199 DOI: 10.1126/science.1246729] [Citation(s) in RCA: 168] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The yeast mitochondrial ABC transporter Atm1, in concert with glutathione, functions in the export of a substrate required for cytosolic-nuclear iron-sulfur protein biogenesis and cellular iron regulation. Defects in the human ortholog ABCB7 cause the sideroblastic anemia XLSA/A. Here, we report the crystal structures of free and glutathione-bound Atm1 in inward-facing, open conformations at 3.06- and 3.38-angstrom resolution, respectively. The glutathione binding site includes a residue mutated in XLSA/A and is located close to the inner membrane surface in a large cavity. The two nucleotide-free adenosine 5'-triphosphate binding domains do not interact yet are kept in close vicinity through tight interaction of the two C-terminal α-helices of the Atm1 dimer. The resulting protein stabilization may be a common structural feature of all ABC exporters.
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Affiliation(s)
- Vasundara Srinivasan
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Strasse 6, 35032 Marburg, Germany
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No laughing matter: the unmaking of the greenhouse gas dinitrogen monoxide by nitrous oxide reductase. Met Ions Life Sci 2014; 14:177-210. [PMID: 25416395 DOI: 10.1007/978-94-017-9269-1_8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The gas nitrous oxide (N₂O) is generated in a variety of abiotic, biotic, and anthropogenic processes and it has recently been under scrutiny for its role as a greenhouse gas. A single enzyme, nitrous oxide reductase, is known to reduce N₂O to uncritical N₂, in a two-electron reduction process that is catalyzed at two unusual metal centers containing copper. Nitrous oxide reductase is a bacterial metalloprotein from the metabolic pathway of denitrification, and it forms a 130 kDa homodimer in which the two metal sites CuA and CuZ from opposing monomers are brought into close contact to form the active site of the enzyme. CuA is a binuclear, valence-delocalized cluster that accepts and transfers a single electron. The CuA site of nitrous oxide reductase is highly similar to that of respiratory heme-copper oxidases, but in the denitrification enzyme the site additionally undergoes a conformational change on a ligand that is suggested to function as a gate for electron transfer from an external donor protein. CuZ, the tetranuclear active center of nitrous oxide reductase, is isolated under mild and anoxic conditions as a unique [4Cu:2S] cluster. It is easily desulfurylated to yield a [4Cu:S] state termed CuZ (*) that is functionally distinct. The CuZ form of the cluster is catalytically active, while CuZ (*) is inactive as isolated in the [3Cu(1+):1Cu(2+)] state. However, only CuZ (*) can be reduced to an all-cuprous state by sodium dithionite, yielding a form that shows higher activities than CuZ. As the possibility of a similar reductive activation in the periplasm is unconfirmed, the mechanism and the actual functional state of the enzyme remain under debate. Using enzyme from anoxic preparations with CuZ in the [4Cu:2S] state, N2O was shown to bind between the CuA and CuZ sites, suggesting direct electron transfer from CuA to the substrate after its activation by CuZ.
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130
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Walden PM, McMahon RM, Archbold JK. Membrane Protein Structures for Rational Antimicrobial Drug Design. Aust J Chem 2014. [DOI: 10.1071/ch14333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Antibiotic resistance is a major global health threat. Bacteria have developed novel resistance mechanisms to many of the latest generations of antibiotics and there is an urgent need to develop new therapies to combat these infections. Infections that are caused by multi-drug resistant Gram-negative bacteria result in poor prognosis, prolonged illness, and greater costs for health care. Recent research has pointed to several key bacterial membrane proteins as potential targets for drug and vaccine development. However, determination of the structures of these membrane proteins is not a trivial task. Here we review recent breakthroughs of the structural determination of bacterial membrane proteins and their potential for the future rational design of novel antimicrobial therapies.
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