1
|
Ma C, Gong C. Considerations in production of the prokaryotic ZIP family transporters for structural and functional studies. Methods Enzymol 2023; 687:1-30. [PMID: 37666628 DOI: 10.1016/bs.mie.2023.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
Zinc ions play essential roles as components of enzymes and many other important biomolecules, and are associated with numerous diseases. The uptake of Zn2+ and other metal ions require a widely distributed transporter protein family called Zrt/Irt-like Proteins (ZIP family), the majority members of which tend to have eight transmembrane helices with both N- and C- termini located on the extracellular or periplasmic side. Their small sizes and dynamic conformations bring many difficulties in their production for structural studies either by crystallography or Cryo-EM. Here, we summarize the problems that may encounter at the various steps of processing the ZIP proteins from gene to structural and functional studies, and provide some solutions and examples from our and other labs for the cloning, expression, purification, stability screening, metal ion transport assays and structural studies of prokaryotic ZIP family transporters using Escherichia coli as a heterologous host.
Collapse
Affiliation(s)
- Cheng Ma
- Protein Facility, Zhejiang University School of Medicine, Hangzhou, P.R. China; The First Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, P.R. China.
| | - Caixia Gong
- The First Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, P.R. China; Zhejiang Provincial Key Laboratory for Diagnosis and Treatment of Aging and Physic-chemical Injury Diseases, Hangzhou, P.R. China.
| |
Collapse
|
2
|
Shaheen A, Ismat F, Iqbal M, Haque A, Ul-Haq Z, Mirza O, De Zorzi R, Walz T, Rahman M. Characterization of the multidrug efflux transporter styMdtM from Salmonella enterica serovar Typhi. Proteins 2021; 89:1193-1204. [PMID: 33983672 PMCID: PMC8338744 DOI: 10.1002/prot.26141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 02/14/2021] [Accepted: 05/07/2021] [Indexed: 11/09/2022]
Abstract
Salmonellae are foodborne pathogens and the major cause of gastroenteritis in humans. Salmonellae express multidrug efflux transporters that play a key role in their drug resistance, which is becoming an increasing problem for therapeutic intervention. Despite their biomedical importance, the mechanisms underlying substrate transport by multidrug efflux transporters remain poorly understood. Here, we describe the first characterization of a multidrug transporter belonging to the major facilitator superfamily from the genus Salmonella. We show that several clinical Salmonella Typhi (S. Typhi) isolates constitutively express the styMdtM (STY4874) gene, which encodes a known multidrug-resistance (MDR) transporter. Guided by the structure of the Escherichia coli (E. coli) homolog, we studied two residues critical for substrate transport, Asp25 and Arg111. Mutation of Asp25 to glutamate did not affect the transport function of styMdtM, whereas mutation to alanine reduced its transport activity, suggesting that a negative charge at this position is critical for substrate translocation across the membrane. Substrate-affinity measurements by intrinsic fluorescence spectroscopy showed that the Asp25Ala mutant retained its capacity to bind substrate, albeit at a lower level. Mutation of Arg111 to alanine resulted in a decrease in secondary structure content of the transporter, and mutation to lysine completely destabilized the structure of the transporter. A homology model of styMdtM suggests that Arg111 is important for stabilizing the transmembrane domain by mediating necessary interactions between neighboring helices. Together, our studies provide new structural and mechanistic insights into the Salmonella MDR transporter styMdtM.
Collapse
Affiliation(s)
- Aqsa Shaheen
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
- Department of Biochemistry and Biotechnology, University of Gujrat, Hafiz Hayat Campus, Gujrat, Pakistan
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Fouzia Ismat
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | - Mazhar Iqbal
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | - Abdul Haque
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
- Akhuwat First University, 250 R.B, Bardakay, Near Abbaspur Railway Station, University Park, Faisalabad, Pakistan
| | - Zaheer Ul-Haq
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Osman Mirza
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rita De Zorzi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
- Current address: Department of Chemical and Pharmaceutical Sciences, University of Trieste, via L. Giorgieri, 1 – 34127 Trieste, Italy
| | - Thomas Walz
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
- Current address: Laboratory of Molecular Electron Microscopy, Rockefeller University, New York, NY 10065, USA
| | - Moazur Rahman
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
- School of Biological Sciences, University of the Punjab, Lahore
| |
Collapse
|
3
|
Shim J, Zhou C, Gong T, Iserlis DA, Linjawi HA, Wong M, Pan T, Tan C. Building protein networks in synthetic systems from the bottom-up. Biotechnol Adv 2021; 49:107753. [PMID: 33857631 PMCID: PMC9558565 DOI: 10.1016/j.biotechadv.2021.107753] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/18/2021] [Accepted: 04/06/2021] [Indexed: 01/01/2023]
Abstract
The recent development of synthetic biology has expanded the capability to design and construct protein networks outside of living cells from the bottom-up. The new capability has enabled us to assemble protein networks for the basic study of cellular pathways, expression of proteins outside cells, and building tissue materials. Furthermore, the integration of natural and synthetic protein networks has enabled new functions of synthetic or artificial cells. Here, we review the underlying technologies for assembling protein networks in liposomes, water-in-oil droplets, and biomaterials from the bottom-up. We cover the recent applications of protein networks in biological transduction pathways, energy self-supplying systems, cellular environmental sensors, and cell-free protein scaffolds. We also review new technologies for assembling protein networks, including multiprotein purification methods, high-throughput assay screen platforms, and controllable fusion of liposomes. Finally, we present existing challenges towards building protein networks that rival the complexity and dynamic response akin to natural systems. This review addresses the gap in our understanding of synthetic and natural protein networks. It presents a vision towards developing smart and resilient protein networks for various biomedical applications.
Collapse
Affiliation(s)
- Jiyoung Shim
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, United States of America
| | - Chuqing Zhou
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, United States of America
| | - Ting Gong
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, United States of America
| | - Dasha Aleksandra Iserlis
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, United States of America
| | - Hamad Abdullah Linjawi
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, United States of America
| | - Matthew Wong
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, United States of America
| | - Tingrui Pan
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, United States of America; Suzhou Institute for Advanced Research, University of Science and Technology, Suzhou, China.
| | - Cheemeng Tan
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, United States of America.
| |
Collapse
|
4
|
Preisler SS, Wiuf AD, Friis M, Kjaergaard L, Hurd M, Becares ER, Nurup CN, Bjoerkskov FB, Szathmáry Z, Gourdon PE, Calloe K, Klaerke DA, Gotfryd K, Pedersen PA. Saccharomyces cerevisiae as a superior host for overproduction of prokaryotic integral membrane proteins. Curr Res Struct Biol 2021; 3:51-71. [PMID: 34235486 PMCID: PMC8244417 DOI: 10.1016/j.crstbi.2021.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 01/02/2023] Open
Abstract
Integral membrane proteins (IMPs) constitute ~30% of all proteins encoded by the genome of any organism and Escherichia coli remains the first-choice host for recombinant production of prokaryotic IMPs. However, the expression levels of prokaryotic IMPs delivered by this bacterium are often low and overproduced targets often accumulate in inclusion bodies. The targets are therefore often discarded to avoid an additional and inconvenient refolding step in the purification protocol. Here we compared expression of five prokaryotic (bacterial and archaeal) IMP families in E. coli and Saccharomyces cerevisiae. We demonstrate that our S. cerevisiae-based production platform is superior in expression of four investigated IMPs, overall being able to deliver high quantities of active target proteins. Surprisingly, in case of the family of zinc transporters (Zrt/Irt-like proteins, ZIPs), S. cerevisiae rescued protein expression that was undetectable in E. coli. We also demonstrate the effect of localization of the fusion tag on expression yield and sample quality in detergent micelles. Lastly, we present a road map to achieve the most efficient expression of prokaryotic IMPs in our yeast platform. Our findings demonstrate the great potential of S. cerevisiae as host for high-throughput recombinant overproduction of bacterial and archaeal IMPs for downstream biophysical characterization. S. cerevisiae is superior to E. coli in expressing correctly folded and active IMPs. S. cerevisiae completely rescues the expression of the family of zinc transporters. Localization of the fusion tag affects expression yields and protein quality. We provide a roadmap to efficient expression of prokaryotic IMPs in S. cerevisiae.
Collapse
Affiliation(s)
- Sarah Spruce Preisler
- Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen, OE, Denmark
| | - Anders Drabaek Wiuf
- Membrane Protein Structural Biology Group, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Maersk Tower 7-9, DK 2200, Copenhagen N, Denmark
| | - Marc Friis
- Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen, OE, Denmark
| | - Lasse Kjaergaard
- Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen, OE, Denmark
| | - Molly Hurd
- University of Copenhagen, Department of Veterinary and Animal Sciences, Dyrlaegevej 100, Frederiksberg, DK, 1870, Denmark
| | - Eva Ramos Becares
- Membrane Protein Structural Biology Group, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Maersk Tower 7-9, DK 2200, Copenhagen N, Denmark
| | - Casper Normann Nurup
- Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen, OE, Denmark
| | | | - Zsófia Szathmáry
- Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen, OE, Denmark
| | - Pontus Emanuel Gourdon
- Membrane Protein Structural Biology Group, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Maersk Tower 7-9, DK 2200, Copenhagen N, Denmark
| | - Kirstine Calloe
- University of Copenhagen, Department of Veterinary and Animal Sciences, Dyrlaegevej 100, Frederiksberg, DK, 1870, Denmark
| | - Dan A Klaerke
- University of Copenhagen, Department of Veterinary and Animal Sciences, Dyrlaegevej 100, Frederiksberg, DK, 1870, Denmark
| | - Kamil Gotfryd
- Membrane Protein Structural Biology Group, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Maersk Tower 7-9, DK 2200, Copenhagen N, Denmark
| | - Per Amstrup Pedersen
- Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen, OE, Denmark
| |
Collapse
|
5
|
Membrane Protein Production and Purification from Escherichia coli and Sf9 Insect Cells. Methods Mol Biol 2021. [PMID: 33582985 DOI: 10.1007/978-1-0716-0724-4_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
A major obstacle to studying membrane proteins by biophysical techniques is the difficulty in producing sufficient amounts of materials for functional and structural studies. To overexpress the target membrane protein heterologously, especially an eukaryotic protein, a key step is to find the optimal host expression system and perform subsequent expression optimization. In this chapter, we describe protocols for screening membrane protein production using bacterial and insect cells, solubilization screening, large-scale production, and commonly used affinity chromatography purification methods. We discuss general optimization conditions, such as promoters and tags, and describe current techniques that can be used in any laboratory without specialized expensive equipment. Especially for insect cells, GFP fusions are particularly useful for localization and in-gel fluorescence detection of the proteins on SDS-PAGE. We give detailed protocols that can be used to screen the best expression and purification conditions for membrane protein study.
Collapse
|
6
|
Zafar M, Shah MA, Shehzad A, Tariq A, Habib M, Muddassar M, Shah MS, Iqbal M, Hemmatzadeh F, Rahman M. Characterization of the highly immunogenic VP2 protrusion domain as a diagnostic antigen for members of Birnaviridae family. Appl Microbiol Biotechnol 2020; 104:3391-3402. [PMID: 32088761 PMCID: PMC7222154 DOI: 10.1007/s00253-020-10458-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 01/31/2020] [Accepted: 02/10/2020] [Indexed: 11/13/2022]
Abstract
Birnaviridae is a family of viruses (birnaviruses) which consists of four genera, members of which cause diseases in fish, birds, mollusks, and insects. The genome of birnaviruses encodes the highly immunogenic VP2 capsid protein. In order to demonstrate that the VP2 protein can be exploited as a diagnostic antigen for birnaviruses, we developed a lateral flow assay based on the surface-exposed VP2 protrusion domain of a representative birnavirus, infectious bursal disease virus (IBDV) of serotype 1 which causes the highly devastating infectious bursal disease in chickens. The biophysical characterization of the purified domain reveals that the domain predominantly consists of β-sheets, exists in a trimeric form, and remains folded at high temperatures, making it suitable for diagnostic purposes. Owing to its highly immunogenic nature and excellent biophysical properties, we employed the VP2 protrusion domain in a gold nanoparticle-based lateral flow assay for rapid detection of anti-IBDV antibodies in serum samples of infected chickens. Our results indicate that the domain binds anti-IBDV antibodies with high specificity during laboratory testing and on-site testing. The lateral flow assay reported here yields comparable results in a qualitative manner as obtained through a commercial enzyme-linked immunosorbent assay (ELISA). As VP2 is a common capsid protein of birnaviruses, the lateral flow assay can be generalized for other birnaviruses, and members of Tetraviridae and Nodaviridae families which contain homologous VP2 capsid proteins.
Collapse
Affiliation(s)
- Maryam Zafar
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan.,Pakistan Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad, Pakistan.,School of Animal and Veterinary Sciences, Roseworthy Campus, The University of Adelaide, Roseworthy, South Australia,, 5371, Australia
| | - Majid Ali Shah
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan.,Pakistan Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad, Pakistan
| | - Aamir Shehzad
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan.,Pakistan Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad, Pakistan
| | - Anam Tariq
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan.,Pakistan Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad, Pakistan
| | - Mudasser Habib
- Vaccine Development Group, Animal Sciences Division, NIAB, Faisalabad, Pakistan
| | - Muhammad Muddassar
- Department of Biosciences, COMSATS-University Islamabad, Park Road, Islamabad, Pakistan
| | | | - Mazhar Iqbal
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan.,Pakistan Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad, Pakistan
| | - Farhid Hemmatzadeh
- School of Animal and Veterinary Sciences, Roseworthy Campus, The University of Adelaide, Roseworthy, South Australia,, 5371, Australia.
| | - Moazur Rahman
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan. .,Pakistan Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad, Pakistan. .,School of Animal and Veterinary Sciences, Roseworthy Campus, The University of Adelaide, Roseworthy, South Australia,, 5371, Australia.
| |
Collapse
|
7
|
Cai H, Yao H, Li T, Tang Y, Li D. High-level heterologous expression of the human transmembrane sterol Δ8,Δ7-isomerase in Pichia pastoris. Protein Expr Purif 2019; 164:105463. [DOI: 10.1016/j.pep.2019.105463] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 07/30/2019] [Indexed: 01/11/2023]
|
8
|
Pedro AQ, Queiroz JA, Passarinha LA. Smoothing membrane protein structure determination by initial upstream stage improvements. Appl Microbiol Biotechnol 2019; 103:5483-5500. [PMID: 31127356 PMCID: PMC7079970 DOI: 10.1007/s00253-019-09873-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 04/25/2019] [Accepted: 04/26/2019] [Indexed: 12/14/2022]
Abstract
Membrane proteins (MP) constitute 20–30% of all proteins encoded by the genome of various organisms and perform a wide range of essential biological functions. However, despite they represent the largest class of protein drug targets, a relatively small number high-resolution 3D structures have been obtained yet. Membrane protein biogenesis is more complex than that of the soluble proteins and its recombinant biosynthesis has been a major drawback, thus delaying their further structural characterization. Indeed, the major limitation in structure determination of MP is the low yield achieved in recombinant expression, usually coupled to low functionality, pinpointing the optimization target in recombinant MP research. Recently, the growing attention that have been dedicated to the upstream stage of MP bioprocesses allowed great advances, permitting the evolution of the number of MP solved structures. In this review, we analyse and discuss effective solutions and technical advances at the level of the upstream stage using prokaryotic and eukaryotic organisms foreseeing an increase in expression yields of correctly folded MP and that may facilitate the determination of their three-dimensional structure. A section on techniques used to protein quality control and further structure determination of MP is also included. Lastly, a critical assessment of major factors contributing for a good decision-making process related to the upstream stage of MP is presented.
Collapse
Affiliation(s)
- Augusto Quaresma Pedro
- CICS-UBI - Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, 6201-001, Covilhã, Portugal
- CICECO - Aveiro Institute of Materials, Department of Chemistry, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - João António Queiroz
- CICS-UBI - Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, 6201-001, Covilhã, Portugal
| | - Luís António Passarinha
- CICS-UBI - Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, 6201-001, Covilhã, Portugal.
- UCIBIO@REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal.
| |
Collapse
|
9
|
Production of membrane proteins for characterisation of their pheromone-sensing and antimicrobial resistance functions. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2018; 47:723-737. [PMID: 30066130 PMCID: PMC6182600 DOI: 10.1007/s00249-018-1325-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 06/08/2018] [Accepted: 07/21/2018] [Indexed: 12/15/2022]
Abstract
Despite the importance of membrane proteins in cellular processes, studies of these hydrophobic proteins present major technical challenges, including expression and purification for structural and biophysical studies. A modified strategy of that proposed previously by Saidijam et al. (2005) and others, for the routine expression of bacterial membrane proteins involved in environmental sensing and antimicrobial resistance (AMR), is proposed which results in purification of sufficient proteins for biophysical experiments. We report expression successes amongst a collection of enterococcal vancomycin resistance membrane proteins: VanTG, VanTG-M transporter domain, VanZ and the previously characterised VanS (A-type) histidine protein kinase (HPK). Using the same strategy, we report on the successful amplification and purification of intact BlpH and ComD2 HPKs of Streptococcus pneumoniae. Near-UV circular dichroism revealed both recombinant proteins bound their pheromone ligands BlpC and CSP2. Interestingly, CSP1 also interacted with ComD. Finally, we evaluate the alternative strategy for studying sensory HPKs involving isolated soluble sensory domain fragments, exemplified by successful production of VicKESD of Enterococcus faecalis VicK. Purified VicKESD possessed secondary structure post-purification. Thermal denaturation experiments using far-UV CD, a technique which can be revealing regarding ligand binding, revealed that: (a) VicKESD denaturation occurs between 15 and 50 °C; and (b) reducing conditions did not detectably affect denaturation profiles suggesting reducing conditions per se are not directly sensed by VicKESD. Our findings provide information on a modified strategy for the successful expression, production and/or storage of bacterial membrane HPKs, AMR proteins and sensory domains for their future crystallisation, and ligand binding studies.
Collapse
|
10
|
Dilworth MV, Piel MS, Bettaney KE, Ma P, Luo J, Sharples D, Poyner DR, Gross SR, Moncoq K, Henderson PJF, Miroux B, Bill RM. Microbial expression systems for membrane proteins. Methods 2018; 147:3-39. [PMID: 29656078 DOI: 10.1016/j.ymeth.2018.04.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/08/2018] [Accepted: 04/10/2018] [Indexed: 12/19/2022] Open
Abstract
Despite many high-profile successes, recombinant membrane protein production remains a technical challenge; it is still the case that many fewer membrane protein structures have been published than those of soluble proteins. However, progress is being made because empirical methods have been developed to produce the required quantity and quality of these challenging targets. This review focuses on the microbial expression systems that are a key source of recombinant prokaryotic and eukaryotic membrane proteins for structural studies. We provide an overview of the host strains, tags and promoters that, in our experience, are most likely to yield protein suitable for structural and functional characterization. We also catalogue the detergents used for solubilization and crystallization studies of these proteins. Here, we emphasize a combination of practical methods, not necessarily high-throughput, which can be implemented in any laboratory equipped for recombinant DNA technology and microbial cell culture.
Collapse
Affiliation(s)
- Marvin V Dilworth
- School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Mathilde S Piel
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, UMR 7099, CNRS, Université Paris Diderot, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Kim E Bettaney
- Astbury Centre for Structural Molecular Biology and School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Pikyee Ma
- Astbury Centre for Structural Molecular Biology and School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Ji Luo
- Astbury Centre for Structural Molecular Biology and School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - David Sharples
- Astbury Centre for Structural Molecular Biology and School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - David R Poyner
- School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Stephane R Gross
- School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Karine Moncoq
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, UMR 7099, CNRS, Université Paris Diderot, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Peter J F Henderson
- Astbury Centre for Structural Molecular Biology and School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK.
| | - Bruno Miroux
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, UMR 7099, CNRS, Université Paris Diderot, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | - Roslyn M Bill
- School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK.
| |
Collapse
|
11
|
Spherical-supported membranes as platforms for screening against membrane protein targets. Anal Biochem 2018; 549:58-65. [PMID: 29545094 PMCID: PMC5948183 DOI: 10.1016/j.ab.2018.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/09/2018] [Accepted: 03/12/2018] [Indexed: 11/23/2022]
Abstract
Screening assays performed against membrane protein targets (e.g. phage display) are hampered by issues arising from protein expression and purification, protein stability in detergent solutions and epitope concealment by detergent micelles. Here, we have studied a fast and simple method to improve screening against membrane proteins: spherical-supported bilayer lipid membranes (“SSBLM”). SSBLMs can be quickly isolated via low-speed centrifugation and redispersed in liquid solutions while presenting the target protein in a native-like lipid environment. To provide proof-of-concept, SSBLMs embedding the polytopic bacterial nucleoside transporter NupC were assembled on 100- and 200 nm silica particles. To test specific binding of antibodies, NupC was tagged with a poly-histidine epitope in one of its central loops between two transmembrane helices. Fluorescent labelling, small angle X-ray scattering (SAXS) and cryo-electron microscopy (cryo-EM) were used to monitor formation of the SSBLMs. Specific binding of an anti-his antibody and a gold-nitrilotriacetic acid (NTA) conjugate probe was confirmed with ELISAs and cryo-EM. SSBLMs for screening could be made with purified and lipid reconstituted NupC, as well as crude bacterial membrane extracts. We conclude that SSBLMs are a promising new means of presenting membrane protein targets for (biomimetic) antibody screening in a native-like lipid environment.
Collapse
|
12
|
Characterisation of the DAACS Family Escherichia coli Glutamate/Aspartate-Proton Symporter GltP Using Computational, Chemical, Biochemical and Biophysical Methods. J Membr Biol 2016; 250:145-162. [DOI: 10.1007/s00232-016-9942-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 12/09/2016] [Indexed: 10/20/2022]
|
13
|
Hetényi A, Hegedűs Z, Fajka-Boja R, Monostori É, Kövér KE, Martinek TA. Target-specific NMR detection of protein-ligand interactions with antibody-relayed 15N-group selective STD. JOURNAL OF BIOMOLECULAR NMR 2016; 66:227-232. [PMID: 27885546 DOI: 10.1007/s10858-016-0076-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 11/07/2016] [Indexed: 06/06/2023]
Abstract
Fragment-based drug design has been successfully applied to challenging targets where the detection of the weak protein-ligand interactions is a key element. 1H saturation transfer difference (STD) NMR spectroscopy is a powerful technique for this work but it requires pure homogeneous proteins as targets. Monoclonal antibody (mAb)-relayed 15N-GS STD spectroscopy has been developed to resolve the problem of protein mixtures and impure proteins. A 15N-labelled target-specific mAb is selectively irradiated and the saturation is relayed through the target to the ligand. Tests on the anti-Gal-1 mAb/Gal-1/lactose system showed that the approach is experimentally feasible in a reasonable time frame. This method allows detection and identification of binding molecules directly from a protein mixture in a multicomponent system.
Collapse
Affiliation(s)
- Anasztázia Hetényi
- Department of Medical Chemistry, University of Szeged, Dóm t. 8., Szeged, 6720, Hungary
| | - Zsófia Hegedűs
- SZTE-MTA Lendület Foldamer Research Group, Institute of Pharmaceutical Analysis Department, University of Szeged, Somogyi u. 4, Szeged, 6720, Hungary
| | - Roberta Fajka-Boja
- Lymphocyte Signal Transduction Laboratory, Institute of Genetics, Biological Research Center of the Hungarian Academy of Sciences, Temesvári krt. 62, Szeged, 6726, Hungary
| | - Éva Monostori
- Lymphocyte Signal Transduction Laboratory, Institute of Genetics, Biological Research Center of the Hungarian Academy of Sciences, Temesvári krt. 62, Szeged, 6726, Hungary
| | - Katalin E Kövér
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1., Debrecen, 4032, Hungary
| | - Tamás A Martinek
- SZTE-MTA Lendület Foldamer Research Group, Institute of Pharmaceutical Analysis Department, University of Szeged, Somogyi u. 4, Szeged, 6720, Hungary.
| |
Collapse
|
14
|
Pandey A, Shin K, Patterson RE, Liu XQ, Rainey JK. Current strategies for protein production and purification enabling membrane protein structural biology. Biochem Cell Biol 2016; 94:507-527. [PMID: 27010607 PMCID: PMC5752365 DOI: 10.1139/bcb-2015-0143] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Membrane proteins are still heavily under-represented in the protein data bank (PDB), owing to multiple bottlenecks. The typical low abundance of membrane proteins in their natural hosts makes it necessary to overexpress these proteins either in heterologous systems or through in vitro translation/cell-free expression. Heterologous expression of proteins, in turn, leads to multiple obstacles, owing to the unpredictability of compatibility of the target protein for expression in a given host. The highly hydrophobic and (or) amphipathic nature of membrane proteins also leads to challenges in producing a homogeneous, stable, and pure sample for structural studies. Circumventing these hurdles has become possible through the introduction of novel protein production protocols; efficient protein isolation and sample preparation methods; and, improvement in hardware and software for structural characterization. Combined, these advances have made the past 10-15 years very exciting and eventful for the field of membrane protein structural biology, with an exponential growth in the number of solved membrane protein structures. In this review, we focus on both the advances and diversity of protein production and purification methods that have allowed this growth in structural knowledge of membrane proteins through X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and cryo-electron microscopy (cryo-EM).
Collapse
Affiliation(s)
- Aditya Pandey
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Kyungsoo Shin
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Robin E. Patterson
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Xiang-Qin Liu
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Jan K. Rainey
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| |
Collapse
|
15
|
Chen Y, Li Q, Yang J, Xie H. Promoting Tag Removal of a MBP-Fused Integral Membrane Protein by TEV Protease. Appl Biochem Biotechnol 2016; 181:939-947. [PMID: 27696139 DOI: 10.1007/s12010-016-2260-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 09/19/2016] [Indexed: 11/30/2022]
Abstract
Tag removal is a prerequisite issue for structural and functional analysis of affinity-purified membrane proteins. The present study took a MBP-fused membrane protein, MrpF, as a model to investigate the tag removal by TEV protease. Influences of the linking sequence between TEV cleavage site and MrpF on protein expression and predicted secondary structure were investigated. The steric accessibility of TEV protease to cleavage site of MBP-fused MrpF was explored. It was found that reducing the size of hydrophilic group of detergents and/or extending the linking sequence between cleavage site and target protein can significantly improve the accessibility of the cleavage site and promote tag removal by TEV protease.
Collapse
Affiliation(s)
- Yanke Chen
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Qichang Li
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan, 430070, China
| | - Jun Yang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China.
| | - Hao Xie
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan, 430070, China.
| |
Collapse
|
16
|
Ma C, Hao Z, Huysmans G, Lesiuk A, Bullough P, Wang Y, Bartlam M, Phillips SE, Young JD, Goldman A, Baldwin SA, Postis VLG. A Versatile Strategy for Production of Membrane Proteins with Diverse Topologies: Application to Investigation of Bacterial Homologues of Human Divalent Metal Ion and Nucleoside Transporters. PLoS One 2015; 10:e0143010. [PMID: 26606682 PMCID: PMC4659628 DOI: 10.1371/journal.pone.0143010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 10/29/2015] [Indexed: 01/01/2023] Open
Abstract
Membrane proteins play key roles in many biological processes, from acquisition of nutrients to neurotransmission, and are targets for more than 50% of current therapeutic drugs. However, their investigation is hampered by difficulties in their production and purification on a scale suitable for structural studies. In particular, the nature and location of affinity tags introduced for the purification of recombinant membrane proteins can greatly influence their expression levels by affecting their membrane insertion. The extent of such effects typically depends on the transmembrane topologies of the proteins, which for proteins of unknown structure are usually uncertain. For example, attachment of oligohistidine tags to the periplasmic termini of membrane proteins often interferes with folding and drastically impairs expression in Escherichia coli. To circumvent this problem we have employed a novel strategy to enable the rapid production of constructs bearing a range of different affinity tags compatible with either cytoplasmic or periplasmic attachment. Tags include conventional oligohistidine tags compatible with cytoplasmic attachment and, for attachment to proteins with a periplasmic terminus, either tandem Strep-tag II sequences or oligohistidine tags fused to maltose binding protein and a signal sequence. Inclusion of cleavage sites for TEV or HRV-3C protease enables tag removal prior to crystallisation trials or a second step of purification. Together with the use of bioinformatic approaches to identify members of membrane protein families with topologies favourable to cytoplasmic tagging, this has enabled us to express and purify multiple bacterial membrane transporters. To illustrate this strategy, we describe here its use to purify bacterial homologues of human membrane proteins from the Nramp and ZIP families of divalent metal cation transporters and from the concentrative nucleoside transporter family. The proteins are expressed in E. coli in a correctly folded, functional state and can be purified in amounts suitable for structural investigations.
Collapse
Affiliation(s)
- Cheng Ma
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Zhenyu Hao
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), College of Environmental Science and Engineering, Nankai University, Tianjin, China
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Gerard Huysmans
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Amelia Lesiuk
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Per Bullough
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom
| | - Yingying Wang
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), College of Environmental Science and Engineering, Nankai University, Tianjin, China
| | - Mark Bartlam
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
- College of Life Sciences, Nankai University, Tianjin, China
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Simon E. Phillips
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxfordshire, United Kingdom
| | - James D. Young
- Department of Physiology, University of Alberta, Edmonton, Canada
| | - Adrian Goldman
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
- College of Life Sciences, Nankai University, Tianjin, China
- Division of Biochemistry, Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Stephen A. Baldwin
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Vincent L. G. Postis
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
- Biomedicine Research Group, Faculty of Health and Social Sciences, Leeds Beckett University, Leeds, LS1 3HE, United Kingdom
- * E-mail:
| |
Collapse
|
17
|
Shaheen A, Ismat F, Iqbal M, Haque A, De Zorzi R, Mirza O, Walz T, Rahman M. Characterization of putative multidrug resistance transporters of the major facilitator-superfamily expressed in Salmonella Typhi. J Infect Chemother 2015; 21:357-62. [PMID: 25724589 DOI: 10.1016/j.jiac.2015.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 12/03/2014] [Accepted: 01/02/2015] [Indexed: 01/11/2023]
Abstract
Multidrug resistance mediated by efflux pumps is a well-known phenomenon in infectious bacteria. Although much work has been carried out to characterize multidrug efflux pumps in Gram-negative and Gram-positive bacteria, such information is still lacking for many deadly pathogens. The aim of this study was to gain insight into the substrate specificity of previously uncharacterized transporters of Salmonella Typhi to identify their role in the development of multidrug resistance. S. Typhi genes encoding putative members of the major facilitator superfamily were cloned and expressed in the drug-hypersensitive Escherichia coli strain KAM42, and tested for transport of 25 antibacterial compounds, including representative antibiotics of various classes, antiseptics, dyes and detergents. Of the 15 tested putative transporters, STY0901, STY2458 and STY4874 exhibited a drug-resistance phenotype. Among these, STY4874 conferred resistance to at least ten of the tested antimicrobials: ciprofloxacin, norfloxacin, levofloxacin, kanamycin, streptomycin, gentamycin, nalidixic acid, chloramphenicol, ethidium bromide, and acriflavine, including fluoroquinolone antibiotics, which were drugs of choice to treat S. Typhi infections. Cell-based functional studies using ethidium bromide and acriflavine showed that STY4874 functions as a H(+)-dependent exporter. These results suggest that STY4874 may be an important drug target, which can now be tested by studying the susceptibility of a STY4874-deficient S. Typhi strain to antimicrobials.
Collapse
Affiliation(s)
- Aqsa Shaheen
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Fouzia Ismat
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | - Mazhar Iqbal
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan
| | - Abdul Haque
- The University of Faisalabad, Faisalabad, Pakistan
| | - Rita De Zorzi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Osman Mirza
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Walz
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Moazur Rahman
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
| |
Collapse
|
18
|
Yamashita M, Shepherd M, Booth WI, Xie H, Postis V, Nyathi Y, Tzokov SB, Poole RK, Baldwin SA, Bullough PA. Structure and function of the bacterial heterodimeric ABC transporter CydDC: stimulation of ATPase activity by thiol and heme compounds. J Biol Chem 2014; 289:23177-23188. [PMID: 24958725 PMCID: PMC4132815 DOI: 10.1074/jbc.m114.590414] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In Escherichia coli, the biogenesis of both cytochrome bd-type quinol oxidases and periplasmic cytochromes requires the ATP-binding cassette-type cysteine/GSH transporter, CydDC. Recombinant CydDC was purified as a heterodimer and found to be an active ATPase both in soluble form with detergent and when reconstituted into a lipid environment. Two-dimensional crystals of CydDC were analyzed by electron cryomicroscopy, and the protein was shown to be made up of two non-identical domains corresponding to the putative CydD and CydC subunits, with dimensions characteristic of other ATP-binding cassette transporters. CydDC binds heme b. Detergent-solubilized CydDC appears to adopt at least two structural states, each associated with a characteristic level of bound heme. The purified protein in detergent showed a weak basal ATPase activity (approximately 100 nmol Pi/min/mg) that was stimulated ∼3-fold by various thiol compounds, suggesting that CydDC could act as a thiol transporter. The presence of heme (either intrinsic or added in the form of hemin) led to a further enhancement of thiol-stimulated ATPase activity, although a large excess of heme inhibited activity. Similar responses of the ATPase activity were observed with CydDC reconstituted into E. coli lipids. These results suggest that heme may have a regulatory role in CydDC-mediated transmembrane thiol transport.
Collapse
Affiliation(s)
- Masao Yamashita
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom and
| | - Mark Shepherd
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom and
| | - Wesley I Booth
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom and
| | - Hao Xie
- School of Biomedical Sciences, The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Vincent Postis
- School of Biomedical Sciences, The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Yvonne Nyathi
- School of Biomedical Sciences, The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Svetomir B Tzokov
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom and
| | - Robert K Poole
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom and
| | - Stephen A Baldwin
- School of Biomedical Sciences, The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Per A Bullough
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom and.
| |
Collapse
|
19
|
New insights into the substrate specificities of proton-coupled oligopeptide transporters from E. coli by a pH sensitive assay. FEBS Lett 2014; 588:560-5. [PMID: 24440353 DOI: 10.1016/j.febslet.2014.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 12/31/2013] [Accepted: 01/03/2014] [Indexed: 11/23/2022]
Abstract
Proton-coupled oligopeptide transporters (POTs) are secondary active transporters that facilitate di- and tripeptide uptake by coupling it to an inward directed proton electrochemical gradient. Here the substrate specificities of Escherichia coli POTs YdgR, YhiP and YjdL were investigated by means of a label free transport assay using the hydrophilic pH sensitive dye pyranine and POT overexpressing E. coli cells. The results confirm and extend the functional knowledge on E. coli POTs. In contrast to previous assumptions, alanine and trialanine appears to be substrates of YjdL, albeit poor compared to dipeptides. Similarly tetraalanine apparently is a substrate of both YdgR and YhiP.
Collapse
|
20
|
Ma P, Varela F, Magoch M, Silva AR, Rosário AL, Brito J, Oliveira TF, Nogly P, Pessanha M, Stelter M, Kletzin A, Henderson PJF, Archer M. An efficient strategy for small-scale screening and production of archaeal membrane transport proteins in Escherichia coli. PLoS One 2013; 8:e76913. [PMID: 24282478 PMCID: PMC3838208 DOI: 10.1371/journal.pone.0076913] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 08/28/2013] [Indexed: 11/30/2022] Open
Abstract
Background Membrane proteins play a key role in many fundamental cellular processes such as transport of nutrients, sensing of environmental signals and energy transduction, and account for over 50% of all known drug targets. Despite their importance, structural and functional characterisation of membrane proteins still remains a challenge, partially due to the difficulties in recombinant expression and purification. Therefore the need for development of efficient methods for heterologous production is essential. Methodology/Principal Findings Fifteen integral membrane transport proteins from Archaea were selected as test targets, chosen to represent two superfamilies widespread in all organisms known as the Major Facilitator Superfamily (MFS) and the 5-Helix Inverted Repeat Transporter superfamily (5HIRT). These proteins typically have eleven to twelve predicted transmembrane helices and are putative transporters for sugar, metabolite, nucleobase, vitamin or neurotransmitter. They include a wide range of examples from the following families: Metabolite-H+-symporter; Sugar Porter; Nucleobase-Cation-Symporter-1; Nucleobase-Cation-Symporter-2; and neurotransmitter-sodium-symporter. Overproduction of transporters was evaluated with three vectors (pTTQ18, pET52b, pWarf) and two Escherichia coli strains (BL21 Star and C43 (DE3)). Thirteen transporter genes were successfully expressed; only two did not express in any of the tested vector-strain combinations. Initial trials showed that seven transporters could be purified and six of these yielded quantities of ≥ 0.4 mg per litre suitable for functional and structural studies. Size-exclusion chromatography confirmed that two purified transporters were almost homogeneous while four others were shown to be non-aggregating, indicating that they are ready for up-scale production and crystallisation trials. Conclusions/Significance Here, we describe an efficient strategy for heterologous production of membrane transport proteins in E. coli. Small-volume cultures (10 mL) produced sufficient amount of proteins to assess their purity and aggregation state. The methods described in this work are simple to implement and can be easily applied to many more membrane proteins.
Collapse
Affiliation(s)
- Pikyee Ma
- Instituto de Tecnologia Quίmica e Biolόgica, Universidade Nova de Lisboa, Oeiras, Portugal
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Kang HJ, Lee C, Drew D. Breaking the barriers in membrane protein crystallography. Int J Biochem Cell Biol 2013; 45:636-44. [DOI: 10.1016/j.biocel.2012.12.018] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Revised: 12/03/2012] [Accepted: 12/21/2012] [Indexed: 10/27/2022]
|
22
|
Postis VGL, Rawlings AE, Lesiuk A, Baldwin SA. Use of Escherichia coli for the production and purification of membrane proteins. Methods Mol Biol 2013; 998:33-54. [PMID: 23529419 DOI: 10.1007/978-1-62703-351-0_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Individual types of ion channels and other membrane proteins are typically expressed only at low levels in their native membranes, rendering their isolation by conventional purification techniques difficult. The heterologous over-expression of such proteins is therefore usually a prerequisite for their purification in amounts suitable for structural and for many functional investigations. The most straightforward expression host, suitable for prokaryote membrane proteins and some proteins from eukaryotes, is the bacterium Escherichia coli. Here we describe the use of this expression system for production of functionally active polytopic membrane proteins and methods for their purification by affinity chromatography in amounts up to tens of milligrams.
Collapse
Affiliation(s)
- Vincent G L Postis
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, UK
| | | | | | | |
Collapse
|
23
|
Abstract
Urea is exploited as a nitrogen source by bacteria, and its breakdown products, ammonia and bicarbonate, are employed to counteract stomach acidity in pathogens such as Helicobacter pylori. Uptake in the latter is mediated by UreI, a UAC (urea amide channel) family member. In the present paper, we describe the structure and function of UACBc, a homologue from Bacillus cereus. The purified channel was found to be permeable not only to urea, but also to other small amides. CD and IR spectroscopy revealed a structure comprising mainly α-helices, oriented approximately perpendicular to the membrane. Consistent with this finding, site-directed fluorescent labelling indicated the presence of seven TM (transmembrane) helices, with a cytoplasmic C-terminus. In detergent, UACBc exists largely as a hexamer, as demonstrated by both cross-linking and size-exclusion chromatography. A 9 Å (1 Å=0.1 nm) resolution projection map obtained by cryo-electron microscopy of two-dimensional crystals shows that the six protomers are arranged in a planar hexameric ring. Each exhibits six density features attributable to TM helices, surrounding a putative central channel, while an additional helix is peripherally located. Bioinformatic analyses allowed individual TM regions to be tentatively assigned to the density features, with the resultant model enabling identification of residues likely to contribute to channel function.
Collapse
|
24
|
Bernaudat F, Frelet-Barrand A, Pochon N, Dementin S, Hivin P, Boutigny S, Rioux JB, Salvi D, Seigneurin-Berny D, Richaud P, Joyard J, Pignol D, Sabaty M, Desnos T, Pebay-Peyroula E, Darrouzet E, Vernet T, Rolland N. Heterologous expression of membrane proteins: choosing the appropriate host. PLoS One 2011; 6:e29191. [PMID: 22216205 PMCID: PMC3244453 DOI: 10.1371/journal.pone.0029191] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 11/22/2011] [Indexed: 11/19/2022] Open
Abstract
Background Membrane proteins are the targets of 50% of drugs, although they only represent 1% of total cellular proteins. The first major bottleneck on the route to their functional and structural characterisation is their overexpression; and simply choosing the right system can involve many months of trial and error. This work is intended as a guide to where to start when faced with heterologous expression of a membrane protein. Methodology/Principal Findings The expression of 20 membrane proteins, both peripheral and integral, in three prokaryotic (E. coli, L. lactis, R. sphaeroides) and three eukaryotic (A. thaliana, N. benthamiana, Sf9 insect cells) hosts was tested. The proteins tested were of various origins (bacteria, plants and mammals), functions (transporters, receptors, enzymes) and topologies (between 0 and 13 transmembrane segments). The Gateway system was used to clone all 20 genes into appropriate vectors for the hosts to be tested. Culture conditions were optimised for each host, and specific strategies were tested, such as the use of Mistic fusions in E. coli. 17 of the 20 proteins were produced at adequate yields for functional and, in some cases, structural studies. We have formulated general recommendations to assist with choosing an appropriate system based on our observations of protein behaviour in the different hosts. Conclusions/Significance Most of the methods presented here can be quite easily implemented in other laboratories. The results highlight certain factors that should be considered when selecting an expression host. The decision aide provided should help both newcomers and old-hands to select the best system for their favourite membrane protein.
Collapse
Affiliation(s)
- Florent Bernaudat
- Institut de Biologie Structurale Jean-Pierre Ebel, CEA, Grenoble, France.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Frelet-Barrand A, Boutigny S, Kunji ERS, Rolland N. Membrane protein expression in Lactococcus lactis. Methods Mol Biol 2010; 601:67-85. [PMID: 20099140 DOI: 10.1007/978-1-60761-344-2_5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Membrane proteins play key roles in cellular physiology, and they are important drug targets. Approximately 25% of all genes identified in sequenced genomes are known to encode membrane proteins; however, the majority have no assigned function. Although the resolution of soluble protein structure has entered the high-throughput stage, only 100 high-resolution structures of membrane proteins have been described until now. Lactococcus lactis is a gram-positive lactic bacterium that has been used traditionally in food fermentations, but it is now used widely in biotechnology for large-scale overproduction of heterologously expressed proteins. Various expression vectors based on either constitutive or inducible promoters exist. The nisin-inducible controlled gene expression (NICE) system is the most suitable for recombinant membrane protein expression allowing for fine control of gene expression based on the autoregulation mechanism of the bacteriocin nisin. Recombinant membrane proteins can be produced with affinity tags for efficient detection and purification from crude membrane protein extracts. The purpose of this chapter is to provide a detailed protocol for the expression of membrane proteins and their detection using the Strep-tag II affinity tag in L. lactis.
Collapse
Affiliation(s)
- Annie Frelet-Barrand
- Laboratoire de Physiologie Cellulaire Végétale, CNRS (UMR-5168)/CEA/INRA (UMR-1200), Université Joseph Fourier, iRTSV, CEA-Grenoble, France.
| | | | | | | |
Collapse
|
26
|
Frelet-Barrand A, Boutigny S, Moyet L, Deniaud A, Seigneurin-Berny D, Salvi D, Bernaudat F, Richaud P, Pebay-Peyroula E, Joyard J, Rolland N. Lactococcus lactis, an alternative system for functional expression of peripheral and intrinsic Arabidopsis membrane proteins. PLoS One 2010; 5:e8746. [PMID: 20098692 PMCID: PMC2808337 DOI: 10.1371/journal.pone.0008746] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 12/18/2009] [Indexed: 11/19/2022] Open
Abstract
Background Despite their functional and biotechnological importance, the study of membrane proteins remains difficult due to their hydrophobicity and their low natural abundance in cells. Furthermore, into established heterologous systems, these proteins are frequently only produced at very low levels, toxic and mis- or unfolded. Lactococcus lactis, a Gram-positive lactic bacterium, has been traditionally used in food fermentations. This expression system is also widely used in biotechnology for large-scale production of heterologous proteins. Various expression vectors, based either on constitutive or inducible promoters, are available for this system. While previously used to produce bacterial and eukaryotic membrane proteins, the ability of this system to produce plant membrane proteins was until now not tested. Methodology/Principal Findings The aim of this work was to test the expression, in Lactococcus lactis, of either peripheral or intrinsic Arabidopsis membrane proteins that could not be produced, or in too low amount, using more classical heterologous expression systems. In an effort to easily transfer genes from Gateway-based Arabidopsis cDNA libraries to the L. lactis expression vector pNZ8148, we first established a cloning strategy compatible with Gateway entry vectors. Interestingly, the six tested Arabidopsis membrane proteins could be produced, in Lactococcus lactis, at levels compatible with further biochemical analyses. We then successfully developed solubilization and purification processes for three of these proteins. Finally, we questioned the functionality of a peripheral and an intrinsic membrane protein, and demonstrated that both proteins were active when produced in this system. Conclusions/Significance Altogether, these data suggest that Lactococcus lactis might be an attractive system for the efficient and functional production of difficult plant membrane proteins.
Collapse
Affiliation(s)
- Annie Frelet-Barrand
- CNRS, Laboratoire de Physiologie Cellulaire Végétale, UMR5168, Grenoble, France
- CEA, DSV, iRTSV, LPCV, Grenoble, France
- INRA, Laboratoire de Physiologie Cellulaire Végétale, UMR1200, Grenoble, France
- Université Joseph Fourier, Laboratoire de Physiologie Cellulaire Végétale, Grenoble, France
| | - Sylvain Boutigny
- CNRS, Laboratoire de Physiologie Cellulaire Végétale, UMR5168, Grenoble, France
- CEA, DSV, iRTSV, LPCV, Grenoble, France
- INRA, Laboratoire de Physiologie Cellulaire Végétale, UMR1200, Grenoble, France
- Université Joseph Fourier, Laboratoire de Physiologie Cellulaire Végétale, Grenoble, France
| | - Lucas Moyet
- CNRS, Laboratoire de Physiologie Cellulaire Végétale, UMR5168, Grenoble, France
- CEA, DSV, iRTSV, LPCV, Grenoble, France
- INRA, Laboratoire de Physiologie Cellulaire Végétale, UMR1200, Grenoble, France
- Université Joseph Fourier, Laboratoire de Physiologie Cellulaire Végétale, Grenoble, France
| | - Aurélien Deniaud
- CEA, IBS Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
- CNRS, IBS Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
- Université Joseph Fourier, IBS Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
| | - Daphné Seigneurin-Berny
- CNRS, Laboratoire de Physiologie Cellulaire Végétale, UMR5168, Grenoble, France
- CEA, DSV, iRTSV, LPCV, Grenoble, France
- INRA, Laboratoire de Physiologie Cellulaire Végétale, UMR1200, Grenoble, France
- Université Joseph Fourier, Laboratoire de Physiologie Cellulaire Végétale, Grenoble, France
- * E-mail:
| | - Daniel Salvi
- CNRS, Laboratoire de Physiologie Cellulaire Végétale, UMR5168, Grenoble, France
- CEA, DSV, iRTSV, LPCV, Grenoble, France
- INRA, Laboratoire de Physiologie Cellulaire Végétale, UMR1200, Grenoble, France
- Université Joseph Fourier, Laboratoire de Physiologie Cellulaire Végétale, Grenoble, France
| | - Florent Bernaudat
- CEA, IBS Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
- CNRS, IBS Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
- Université Joseph Fourier, IBS Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
| | - Pierre Richaud
- CEA, DSV, iBEB, Laboratoire des Echanges Membranaires et Signalisation, St Paul les Durance, France
- CNRS, UMR 6191, St Paul les Durance, France
- Université Aix-Marseille, St Paul les Durance, France
| | - Eva Pebay-Peyroula
- CEA, IBS Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
- CNRS, IBS Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
- Université Joseph Fourier, IBS Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
| | - Jacques Joyard
- CNRS, Laboratoire de Physiologie Cellulaire Végétale, UMR5168, Grenoble, France
- CEA, DSV, iRTSV, LPCV, Grenoble, France
- INRA, Laboratoire de Physiologie Cellulaire Végétale, UMR1200, Grenoble, France
- Université Joseph Fourier, Laboratoire de Physiologie Cellulaire Végétale, Grenoble, France
| | - Norbert Rolland
- CNRS, Laboratoire de Physiologie Cellulaire Végétale, UMR5168, Grenoble, France
- CEA, DSV, iRTSV, LPCV, Grenoble, France
- INRA, Laboratoire de Physiologie Cellulaire Végétale, UMR1200, Grenoble, France
- Université Joseph Fourier, Laboratoire de Physiologie Cellulaire Végétale, Grenoble, France
| |
Collapse
|
27
|
Ernst HA, Pham A, Hald H, Kastrup JS, Rahman M, Mirza O. Ligand binding analyses of the putative peptide transporter YjdL from E. coli display a significant selectivity towards dipeptides. Biochem Biophys Res Commun 2009; 389:112-6. [PMID: 19703419 DOI: 10.1016/j.bbrc.2009.08.098] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Accepted: 08/17/2009] [Indexed: 11/19/2022]
Abstract
Proton-dependent oligopeptide transporters (POTs) are secondary active transporters that couple the inwards translocation of di- and tripeptides to inwards proton translocation. Escherichia coli contains four genes encoding the putative POT proteins YhiP, YdgR, YjdL and YbgH. We have over-expressed the previously uncharacterized YjdL and investigated the peptide specificity by means of uptake inhibition. The IC(50) value for the dipeptide Ala-Ala was measured to 22 mM while Ala-Ala-Ala was not able to inhibit uptake. In addition, IC(50) values of 0.3 mM and 1.5 mM were observed for Ala-Lys and Tyr-Ala, respectively, while the alanyl-extended tripeptides Ala-Lys-Ala, Ala-Ala-Lys, Ala-Tyr-Ala and Tyr-Ala-Ala displayed values of 8, >50, 31 and 31 mM, respectively. These results clearly indicate that unlike most POT members characterized to date, including YdgR and YhiP, YjdL shows significantly higher specificity towards dipeptides.
Collapse
Affiliation(s)
- Heidi A Ernst
- Biostructural Research, Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | | | | | | | | | | |
Collapse
|
28
|
Probing metal ion substrate-binding to theE. coliZitB exporter in native membranes by solid state NMR. Mol Membr Biol 2009; 25:683-90. [DOI: 10.1080/09687680802495267] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
29
|
Roach PCJ, Postis VLG, Deacon SE, Wright GSA, Ingram JC, Xia X, McPherson MJ, Baldwin SA. Large-scale preparation of bacterial cell membranes by tangential flow filtration. Mol Membr Biol 2009; 25:609-16. [DOI: 10.1080/09687680802530451] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
30
|
Deacon SE, Roach PCJ, Postis VLG, Wright GSA, Xia X, Phillips SEV, Knox JP, Henderson PJF, McPherson MJ, Baldwin SA. Reliable scale-up of membrane protein over-expression by bacterial auto-induction: from microwell plates to pilot scale fermentations. Mol Membr Biol 2009; 25:588-98. [PMID: 19023695 DOI: 10.1080/09687680802511774] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The production of well-ordered crystals of membrane proteins for structural investigation by X-ray diffraction typically requires extensive crystallization trials and may involve the screening of multiple detergents, lipids and other additives. Purification of sufficient amounts of protein for such trials is hampered by the fact that even when over-expressed, membrane proteins represent only a small percentage of the total protein content of bacteria. Fermentation-scale cultures of cells are therefore usually required. To maximize the efficiency and reduce the cost of such cultures, in the UK Membrane Protein Structure Initiative we have systematically investigated the use of auto-induction as an alternative to induction of expression with isopropyl-beta-D-thiogalactoside. We report here the benefits of first optimizing expression on a multiwell plate scale by systematically varying the concentrations of glucose, glycerol, lactose and succinate present in the auto-induction medium. For subsequent scale-up, comparison of isopropyl-beta-D-thiogalactoside induction in shake-flasks with auto-induction in shake-flasks and in 1L fermenters without and with control of pH and aeration revealed that highest yields of target protein were obtained using the latter culture conditions. However, analysis of the time-course of expression highlighted the importance of choosing the correct time for harvest. The high yields of target protein that can be obtained in a single batch by auto-induction, performed on a 30 l scale in a fermenter, obviate batch-to-batch variations that can add an unwanted variable to crystallization screening experiments. The approach described should therefore be of great utility for membrane protein production for structural studies.
Collapse
Affiliation(s)
- Sarah E Deacon
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Xia X, Postis VLG, Rahman M, Wright GSA, Roach PCJ, Deacon SE, Ingram JC, Henderson PJF, Findlay JBC, Phillips SEV, McPherson MJ, Baldwin SA. Investigation of the structure and function of a Shewanella oneidensis arsenical-resistance family transporter. Mol Membr Biol 2009; 25:691-705. [PMID: 19039703 DOI: 10.1080/09687680802535930] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The toxic metalloid arsenic is an abundant element and most organisms possess transport systems involved in its detoxification. One such family of arsenite transporters, the ACR3 family, is widespread in fungi and bacteria. To gain a better understanding of the molecular mechanism of arsenic transport, we report here the expression and characterization of a family member, So_ACR3, from the bacterium Shewanella oneidensis MR-1. Surprisingly, expression of this transporter in the arsenic-hypersensitive Escherichia coli strain AW3110 conferred resistance to arsenate, but not to arsenite. Purification of a C-terminally His-tagged form of the protein allowed the binding of putative permeants to be directly tested: arsenate but not arsenite quenched its intrinsic fluorescence in a concentration-dependent fashion. Fourier transform infrared spectroscopy showed that the purified protein was predominantly alpha-helical. A mutant bearing a single cysteine residue at position 3 retained the ability to confer arsenate resistance, and was accessible to membrane impermeant thiol reagents in intact cells. In conjunction with successful C-terminal tagging with oligohistidine, this finding is consistent with the experimentally-determined topology of the homologous human apical sodium-dependent bile acid transporter, namely 7 transmembrane helices and a periplasmic N-terminus, although the presence of additional transmembrane segments cannot be excluded. Mutation to alanine of the conserved residue proline 190, in the fourth putative transmembrane region, abrogated the ability of the transporter to confer arsenic resistance, but did not prevent arsenate binding. An apparently increased thermal stability is consistent with the mutant being unable to undergo the conformational transitions required for permeant translocation.
Collapse
Affiliation(s)
- Xiaobing Xia
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Courville P, Urbankova E, Rensing C, Chaloupka R, Quick M, Cellier MFM. Solute carrier 11 cation symport requires distinct residues in transmembrane helices 1 and 6. J Biol Chem 2008; 283:9651-8. [PMID: 18227061 DOI: 10.1074/jbc.m709906200] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ubiquitous solute carriers 11 (SLC11) contribute to metal-ion homeostasis by importing Me(2+) and H(+) into the cytoplasm. To identify residues mediating cation symport, Escherichia coli proton-dependent manganese transporter (MntH) was mutated at five SLC11-specific transmembrane (TM) sites; each mutant activity was compared with wild-type MntH, and the biochemical results were tested by homology threading. Cd(2+) and H(+) uptake kinetics were analyzed in whole cells as a function of pH and temperature, and right-side out membrane vesicles were used to detail energy requirements and to probe site accessibility by Cys replacement and thiol modification. This approach revealed that TM segment 1 (TMS1) residue Asp(34) couples H(+) and Me(2+) symport and contributes to MntH forward transport electrogenicity, whereas the TMS6 His(211) residue mediates pH-dependent Me(2+) uptake; MntH Asn(37), Asn(250), and Asn(401) in TMS1, TMS7, and TMS11 participate in transporter cycling and/or helix packing interactions. These biochemical results fit the LeuT/SLC6 structural fold, which suggests that conserved peptide motifs Asp(34)-Pro-Gly (TMS1) and Met-Pro-His(211) (TMS6) form antiparallel "TM helix/extended peptide" boundaries, lining a "pore" cavity and enabling H(+)-dependent Me(2+) import.
Collapse
Affiliation(s)
- Pascal Courville
- INRS-Institut Armand-Frappier, 531 Boulevard des prairies, Laval, Québec, Canada
| | | | | | | | | | | |
Collapse
|