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O'Brien ES, Fuglestad B, Lessen HJ, Stetz MA, Lin DW, Marques BS, Gupta K, Fleming KG, Wand AJ. Membrane Proteins Have Distinct Fast Internal Motion and Residual Conformational Entropy. Angew Chem Int Ed Engl 2020; 59:11108-11114. [PMID: 32277554 PMCID: PMC7318686 DOI: 10.1002/anie.202003527] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Indexed: 12/31/2022]
Abstract
The internal motions of integral membrane proteins have largely eluded comprehensive experimental characterization. Here the fast side-chain dynamics of the α-helical sensory rhodopsin II and the β-barrel outer membrane protein W have been investigated in lipid bilayers and detergent micelles by solution NMR relaxation techniques. Despite their differing topologies, both proteins have a similar distribution of methyl-bearing side-chain motion that is largely independent of membrane mimetic. The methyl-bearing side chains of both proteins are, on average, more dynamic in the ps-ns timescale than any soluble protein characterized to date. Accordingly, both proteins retain an extraordinary residual conformational entropy in the folded state, which provides a counterbalance to the absence of the hydrophobic effect. Furthermore, the high conformational entropy could greatly influence the thermodynamics underlying membrane-protein functions, including ligand binding, allostery, and signaling.
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Affiliation(s)
- Evan S. O'Brien
- Department of Biochemistry & BiophysicsUniversity of PennsylvaniaPerelman School of MedicinePhiladelphiaPA19104USA
| | - Brian Fuglestad
- Department of Biochemistry & BiophysicsUniversity of PennsylvaniaPerelman School of MedicinePhiladelphiaPA19104USA
- Present address: Department of ChemistryVirginia Commonwealth UniversityRichmondVA23284USA
| | - Henry J. Lessen
- Department of BiophysicsJohns Hopkins UniversityBaltimoreMD21218USA
| | - Matthew A. Stetz
- Department of Biochemistry & BiophysicsUniversity of PennsylvaniaPerelman School of MedicinePhiladelphiaPA19104USA
| | - Danny W. Lin
- Department of Biochemistry & BiophysicsUniversity of PennsylvaniaPerelman School of MedicinePhiladelphiaPA19104USA
| | - Bryan S. Marques
- Department of Biochemistry & BiophysicsUniversity of PennsylvaniaPerelman School of MedicinePhiladelphiaPA19104USA
| | - Kushol Gupta
- Department of Biochemistry & BiophysicsUniversity of PennsylvaniaPerelman School of MedicinePhiladelphiaPA19104USA
| | - Karen G. Fleming
- Department of BiophysicsJohns Hopkins UniversityBaltimoreMD21218USA
| | - A. Joshua Wand
- Department of Biochemistry & BiophysicsTexas A&M UniversityCollege StationTX77843USA
- Department of Biochemistry & BiophysicsUniversity of PennsylvaniaPerelman School of MedicinePhiladelphiaPA19104USA
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2
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O'Brien ES, Fuglestad B, Lessen HJ, Stetz MA, Lin DW, Marques BS, Gupta K, Fleming KG, Wand AJ. Membrane Proteins Have Distinct Fast Internal Motion and Residual Conformational Entropy. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202003527] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Evan S. O'Brien
- Department of Biochemistry & Biophysics University of Pennsylvania Perelman School of Medicine Philadelphia PA 19104 USA
| | - Brian Fuglestad
- Department of Biochemistry & Biophysics University of Pennsylvania Perelman School of Medicine Philadelphia PA 19104 USA
- Present address: Department of Chemistry Virginia Commonwealth University Richmond VA 23284 USA
| | - Henry J. Lessen
- Department of Biophysics Johns Hopkins University Baltimore MD 21218 USA
| | - Matthew A. Stetz
- Department of Biochemistry & Biophysics University of Pennsylvania Perelman School of Medicine Philadelphia PA 19104 USA
| | - Danny W. Lin
- Department of Biochemistry & Biophysics University of Pennsylvania Perelman School of Medicine Philadelphia PA 19104 USA
| | - Bryan S. Marques
- Department of Biochemistry & Biophysics University of Pennsylvania Perelman School of Medicine Philadelphia PA 19104 USA
| | - Kushol Gupta
- Department of Biochemistry & Biophysics University of Pennsylvania Perelman School of Medicine Philadelphia PA 19104 USA
| | - Karen G. Fleming
- Department of Biophysics Johns Hopkins University Baltimore MD 21218 USA
| | - A. Joshua Wand
- Department of Biochemistry & Biophysics Texas A&M University College Station TX 77843 USA
- Department of Biochemistry & Biophysics University of Pennsylvania Perelman School of Medicine Philadelphia PA 19104 USA
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3
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Wiseman DN, Otchere A, Patel JH, Uddin R, Pollock NL, Routledge SJ, Rothnie AJ, Slack C, Poyner DR, Bill RM, Goddard AD. Expression and purification of recombinant G protein-coupled receptors: A review. Protein Expr Purif 2020; 167:105524. [PMID: 31678667 PMCID: PMC6983937 DOI: 10.1016/j.pep.2019.105524] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 10/28/2019] [Accepted: 10/29/2019] [Indexed: 01/15/2023]
Abstract
Given their extensive role in cell signalling, GPCRs are significant drug targets; despite this, many of these receptors have limited or no available prophylaxis. Novel drug design and discovery significantly rely on structure determination, of which GPCRs are typically elusive. Progress has been made thus far to produce sufficient quantity and quality of protein for downstream analysis. As such, this review highlights the systems available for recombinant GPCR expression, with consideration of their advantages and disadvantages, as well as examples of receptors successfully expressed in these systems. Additionally, an overview is given on the use of detergents and the styrene maleic acid (SMA) co-polymer for membrane solubilisation, as well as purification techniques.
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Affiliation(s)
- Daniel N Wiseman
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK.
| | - Abigail Otchere
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK.
| | - Jaimin H Patel
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK.
| | - Romez Uddin
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK.
| | | | - Sarah J Routledge
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK.
| | - Alice J Rothnie
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK.
| | - Cathy Slack
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK.
| | - David R Poyner
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK.
| | - Roslyn M Bill
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK.
| | - Alan D Goddard
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK.
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4
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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]
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5
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Kleist AB, Peterson F, Tyler RC, Gustavsson M, Handel TM, Volkman BF. Solution NMR spectroscopy of GPCRs: Residue-specific labeling strategies with a focus on 13C-methyl methionine labeling of the atypical chemokine receptor ACKR3. Methods Cell Biol 2018; 149:259-288. [PMID: 30616824 DOI: 10.1016/bs.mcb.2018.09.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The past decade has witnessed remarkable progress in the determination of G protein-coupled receptor (GPCR) structures, profoundly expanding our understanding of how GPCRs recognize ligands, become activated, and interact with intracellular signaling components. In recent years, numerous studies have used solution nuclear magnetic resonance (NMR) spectroscopy to investigate GPCRs, providing fundamental insights into GPCR conformational changes, allostery, dynamics, and other facets of GPCR function are challenging to study using other structural techniques. Despite these advantages, NMR-based studies of GPCRs are few relative to the number of published structures, due in part to the challenges and limitations of NMR for the characterization of large membrane proteins. Several studies have circumvented these challenges using a variety of isotopic labeling strategies, including side chain derivatization and metabolic incorporation of NMR-active nuclei. In this chapter, we provide an overview of different isotopic labeling strategies and describe an in-depth protocol for the expression, purification, and NMR studies of the chemokine GPCR atypical chemokine receptor 3 (ACKR3) via 13CH3-methionine incorporation. The goal of this chapter is to provide a resource to the GPCR community for those interested in pursuing NMR studies of GPCRs.
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Affiliation(s)
- Andrew B Kleist
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Francis Peterson
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Robert C Tyler
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Martin Gustavsson
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, CA, United States
| | - Tracy M Handel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, CA, United States
| | - Brian F Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, United States.
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Expression, Purification and Characterization of the Human Cannabinoid 1 Receptor. Sci Rep 2018; 8:2935. [PMID: 29440756 PMCID: PMC5811539 DOI: 10.1038/s41598-018-19749-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 01/04/2018] [Indexed: 12/12/2022] Open
Abstract
The human cannabinoid 1 receptor (hCB1) is involved in numerous physiological processes and therefore provides a wide scope of potential therapeutic opportunities to treat maladies such as obesity, cardio-metabolic disorders, substance abuse, neuropathic pain, and multiple sclerosis. Structure-based drug design using the current knowledge of the hCB1 receptor binding site is limited and requires purified active protein. Heterologous expression and purification of functional hCB1 has been the bottleneck for ligand binding structural studies using biophysical methods such as mass spectrometry, x-ray crystallography and NMR. We constructed several plasmids for in-cell or in vitro Escherichia coli (E. coli) based expression of truncated and stabilized hCB1 receptor (hΔCB1 and hΔCB1T4L) variants and evaluated their competency to bind the CP-55,940 ligand. MALDI-TOF MS analysis of in vitro expressed and purified hΔCB1T4Lhis6 variants, following trypsin digestion, generated ~80% of the receptor sequence coverage. Our data demonstrate the feasibility of a cell-free expression system as a promising part of the strategy for the elucidation of ligand binding sites of the hCB1 receptor using a "Ligand Assisted Protein Structure" (LAPS) approach.
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Fracchiolla KE, Cohen LS, Arshava B, Poms M, Zerbe O, Becker JM, Naider F. Structural characterization of triple transmembrane domain containing fragments of a yeast G protein-coupled receptor in an organic : aqueous environment by solution-state NMR spectroscopy. J Pept Sci 2015; 21:212-22. [PMID: 25645975 DOI: 10.1002/psc.2750] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 12/26/2014] [Accepted: 12/28/2014] [Indexed: 01/09/2023]
Abstract
This report summarizes recent biophysical and protein expression experiments on polypeptides containing the N-terminus, the first, second, and third transmembrane (TM) domains and the contiguous loops of the α-factor receptor Ste2p, a G protein-coupled receptor. The 131-residue polypeptide Ste2p(G31-R161), TM1-TM3, was investigated by solution NMR in trifluoroethanol/water. TM1-TM3 contains helical TM domains at the predicted locations, supported by continuous sets of medium-range NOEs. In addition, a short helix N-terminal to TM1 was detected, as well as a short helical stretch in the first extracellular loop. Two 161-residue polypeptides, [Ste2p(M1-R161), NT-TM1-TM3], that contain the entire N-terminal sequence, one with a single mutation, were directly expressed and isolated from Escherichia coli in yields as high as 30 mg/L. Based on its increased stability, the L11P mutant will be used in future experiments to determine long-range interactions. The study demonstrated that 3-TM domains of a yeast G protein-coupled receptor can be produced in isotopically labeled form suitable for solution NMR studies. The quality of spectra is superior to data recorded in micelles and allows more rapid data analysis. No tertiary contacts have been determined, and if present, they are likely transient. This observation supports earlier studies by us that secondary structure was retained in smaller fragments, both in organic solvents and in detergent micelles, but that stable tertiary contacts may only be present when the protein is imbedded in lipids.
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Affiliation(s)
- Katrina E Fracchiolla
- Department of Chemistry, The College of Staten Island, City University of New York, Staten Island, NY, 10314, USA; Department of Biochemistry, The Graduate Center, City University of New York, New York, NY, 10016, USA
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Cohen LS, Fracchiolla KE, Becker J, Naider F. Invited review GPCR structural characterization: Using fragments as building blocks to determine a complete structure. Biopolymers 2014; 102:223-43. [DOI: 10.1002/bip.22490] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 03/24/2014] [Accepted: 03/27/2014] [Indexed: 12/30/2022]
Affiliation(s)
- Leah S. Cohen
- Department of Chemistry; The College of Staten Island, City University of New York (CUNY); Staten Island NY 10314
| | - Katrina E. Fracchiolla
- Department of Chemistry; The College of Staten Island, City University of New York (CUNY); Staten Island NY 10314
| | - Jeff Becker
- Department of Microbiology; University of Tennessee; Knoxville TN 37996
| | - Fred Naider
- Department of Chemistry; The College of Staten Island, City University of New York (CUNY); Staten Island NY 10314
- Department of Biochemistry; The Graduate Center; CUNY NY 10016-4309
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9
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Wiktor M, Morin S, Sass HJ, Kebbel F, Grzesiek S. Biophysical and structural investigation of bacterially expressed and engineered CCR5, a G protein-coupled receptor. JOURNAL OF BIOMOLECULAR NMR 2013; 55:79-95. [PMID: 23229639 DOI: 10.1007/s10858-012-9688-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 11/22/2012] [Indexed: 06/01/2023]
Abstract
The chemokine receptor CCR5 belongs to the class of G protein-coupled receptors. Besides its role in leukocyte trafficking, it is also the major HIV-1 coreceptor and hence a target for HIV-1 entry inhibitors. Here, we report Escherichia coli expression and a broad range of biophysical studies on E. coli-produced CCR5. After systematic screening and optimization, we obtained 10 mg of purified, detergent-solubilized, folded CCR5 from 1L culture in a triply isotope-labeled ((2)H/(15)N/(13)C) minimal medium. Thus the material is suitable for NMR spectroscopic studies. The expected α-helical secondary structure content is confirmed by circular dichroism spectroscopy. The solubilized CCR5 is monodisperse and homogeneous as judged by transmission electron microscopy. Interactions of CCR5 with its ligands, RANTES and MIP-1β were assessed by surface plasmon resonance yielding K(D) values in the nanomolar range. Using size exclusion chromatography, stable monomeric CCR5 could be isolated. We show that cysteine residues affect both the yield and oligomer distribution of CCR5. HSQC spectra suggest that the transmembrane domains of CCR5 are in equilibrium between several conformations. In addition we present a model of CCR5 based on the crystal structure of CXCR4 as a starting point for protein engineering.
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Affiliation(s)
- Maciej Wiktor
- Focal Area Structural Biology and Biophysics, Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
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Potetinova Z, Tantry S, Cohen LS, Caroccia KE, Arshava B, Becker JM, Naider F. Large multiple transmembrane domain fragments of a G protein-coupled receptor: biosynthesis, purification, and biophysical studies. Biopolymers 2012; 98:485-500. [PMID: 23203693 PMCID: PMC3542537 DOI: 10.1002/bip.22122] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 06/01/2012] [Accepted: 07/02/2012] [Indexed: 01/04/2023]
Abstract
To conduct biophysical analyses on large domains of GPCRs, multimilligram quantities of highly homogeneous proteins are necessary. This communication discusses the biosynthesis of four transmembrane and five transmembrane-containing fragments of Ste2p, a GPCR recognizing the Saccharomyces cerevisiae tridecapeptide pheromone α-factor. The target fragments contained the predicted four N-terminal Ste2p[G(31) -A(198) ] (4TMN), four C-terminal Ste2p[T(155) -L(340) ] (4TMC), or five C-terminal Ste2p[I(120) -L(340) ] (5TMC) transmembrane segments of Ste2p. 4TMN was expressed as a fusion protein using a modified pMMHa vector in L-arabinose-induced Escherichia coli BL21-AI, and cleaved with cyanogen bromide. 4TMC and 5TMC were obtained by direct expression using a pET21a vector in IPTG-induced E. coli BL21(DE3) cells. 4TMC and 5TMC were biosynthesized on a preparative scale, isolated in multimilligram amounts, characterized by MS and investigated by biophysical methods. CD spectroscopy indicated the expected highly α-helical content for 4TMC and 5TMC in membrane mimetic environments. Tryptophan fluorescence showed that 5TMC integrated into the nonpolar region of 1-stearoyl-2-hydroxy-sn-glycero-3-phospho-(1'-rac-glycerol) micelles. HSQC-TROSY investigations revealed that [(15) N]-labeled 5TMC in 50% trifluoroethanol-d(2) /H(2) O/0.05%-trifluoroacetic acid was stable enough to conduct long multidimensional NMR measurements. The entire Ste2p GPCR was not readily reconstituted from the first two and last five or first three and last four transmembrane domains.
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Affiliation(s)
- Zhanna Potetinova
- Department of Chemistry, College of Staten Island, The City University of New York, Staten Island, NY 10314, USA
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Cohen LS, Arshava B, Neumoin A, Becker JM, Güntert P, Zerbe O, Naider F. Comparative NMR analysis of an 80-residue G protein-coupled receptor fragment in two membrane mimetic environments. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2674-84. [PMID: 21791199 DOI: 10.1016/j.bbamem.2011.07.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 06/17/2011] [Accepted: 07/12/2011] [Indexed: 01/09/2023]
Abstract
Fragments of integral membrane proteins have been used to study the physical chemical properties of regions of transporters and receptors. Ste2p(G31-T110) is an 80-residue polypeptide which contains a portion of the N-terminal domain, transmembrane domain 1 (TM1), intracellular loop 1, TM2 and part of extracellular loop 1 of the α-factor receptor (Ste2p) from Saccharomyces cerevisiae. The structure of this peptide was previously determined to form a helical hairpin in lyso-palmitoylphosphatidyl-glycerol micelles (LPPG) [1]. Herein, we perform a systematic comparison of the structure of this protein fragment in micelles and trifluoroethanol (TFE):water in order to understand whether spectra recorded in organic:aqueous medium can facilitate the structure determination in a micellar environment. Using uniformly labeled peptide and peptide selectively protonated on Ile, Val and Leu methyl groups in a perdeuterated background and a broad set of 3D NMR experiments we assigned 89% of the observable atoms. NOEs and chemical shift analysis were used to define the helical regions of the fragment. Together with constraints from paramagnetic spin labeling, NOEs were used to calculate a transiently folded helical hairpin structure for this peptide in TFE:water. Correlation of chemical shifts was insufficient to transfer assignments from TFE:water to LPPG spectra in the absence of further information.
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Affiliation(s)
- L S Cohen
- Department of Chemistry, The College of Staten Island, City University of New York, Staten Island, NY 10314, USA
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12
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Solution- and solid-state NMR studies of GPCRs and their ligands. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1462-75. [DOI: 10.1016/j.bbamem.2010.10.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2010] [Revised: 10/02/2010] [Accepted: 10/05/2010] [Indexed: 12/29/2022]
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Howell SC, Mittal R, Huang L, Travis B, Breyer RM, Sanders CR. CHOBIMALT: a cholesterol-based detergent. Biochemistry 2011; 49:9572-83. [PMID: 20919740 DOI: 10.1021/bi101334j] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cholesterol and its hemisuccinate and sulfate derivatives are widely used in studies of purified membrane proteins but are difficult to solubilize in aqueous solution, even in the presence of detergent micelles. Other cholesterol derivatives do not form conventional micelles and lead to viscous solutions. To address these problems, a cholesterol-based detergent, CHOBIMALT, has been synthesized and characterized. At concentrations above 3−4 μM, CHOBIMALT forms micelles without the need for elevated temperatures or sonic disruption. Diffusion and fluorescence measurements indicated that CHOBIMALT micelles are large (210±30 kDa). The ability to solubilize a functional membrane protein was explored using a G-protein coupled receptor, the human kappa opioid receptor type 1 (hKOR1). While CHOBIMALT alone was not found to be effective as a surfactant for membrane extraction, when added to classical detergent micelles CHOBIMALT was observed to dramatically enhance the thermal stability of solubilized hKOR1.
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Affiliation(s)
- Stanley C Howell
- Department of Biochemistry, Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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Caroccia KE, Estephan R, Cohen LS, Arshava B, Hauser M, Zerbe O, Becker JM, Naider F. Expression and biophysical analysis of a triple-transmembrane domain-containing fragment from a yeast G protein-coupled receptor. Biopolymers 2011; 96:757-71. [DOI: 10.1002/bip.21614] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Park SH, Casagrande F, Das BB, Albrecht L, Chu M, Opella SJ. Local and global dynamics of the G protein-coupled receptor CXCR1. Biochemistry 2011; 50:2371-80. [PMID: 21323370 DOI: 10.1021/bi101568j] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The local and global dynamics of the chemokine receptor CXCR1 are characterized using a combination of solution NMR and solid-state NMR experiments. In isotropic bicelles (q = 0.1), only 13% of the expected number of backbone amide resonances is observed in (1)H/(15)N HSQC solution NMR spectra of uniformly (15)N-labeled samples; extensive deuteration and the use of TROSY made little difference in the 800 MHz spectra. The limited number of observed amide signals is ascribed to mobile backbone sites and assigned to specific residues in the protein; 19 of the signals are from residues at the N-terminus and 25 from residues at the C-terminus. The solution NMR spectra display no evidence of local backbone motions from residues in the transmembrane helices or interhelical loops of CXCR1. This finding is reinforced by comparisons of solid-state NMR spectra of both magnetically aligned and unoriented bilayers containing either full-length or doubly N- and C-terminal truncated CXCR1 constructs. CXCR1 undergoes rapid rotational diffusion about the normal of liquid crystalline phospholipid bilayers; reductions in the frequency span and a change to axial symmetry are observed for both carbonyl carbon and amide nitrogen chemical shift powder patterns of unoriented samples containing (13)C- and (15)N-labeled CXCR1. In contrast, when the phospholipids are in the gel phase, CXCR1 does not undergo rapid global reorientation on the 10(4) Hz time scale defined by the carbonyl carbon and amide nitrogen chemical shift powder patterns.
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Affiliation(s)
- Sang Ho Park
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0307, United States
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16
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Fan Y, Shi L, Ladizhansky V, Brown LS. Uniform isotope labeling of a eukaryotic seven-transmembrane helical protein in yeast enables high-resolution solid-state NMR studies in the lipid environment. JOURNAL OF BIOMOLECULAR NMR 2011; 49:151-161. [PMID: 21246256 DOI: 10.1007/s10858-011-9473-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 01/07/2011] [Indexed: 05/30/2023]
Abstract
Overexpression of isotope-labeled multi-spanning eukaryotic membrane proteins for structural NMR studies is often challenging. On the one hand, difficulties with achieving proper folding, membrane insertion, and native-like post-translational modifications frequently disqualify bacterial expression systems. On the other hand, eukaryotic cell cultures can be prohibitively expensive. One of the viable alternatives, successfully used for producing proteins for solution NMR studies, is yeast expression systems, particularly Pichia pastoris. We report on successful implementation and optimization of isotope labeling protocols, previously used for soluble secreted proteins, to produce homogeneous samples of a eukaryotic seven-transmembrane helical protein, rhodopsin from Leptosphaeria maculans. Even in shake-flask cultures, yields exceeded 5 mg of purified uniformly (13)C,(15)N-labeled protein per liter of culture. The protein was stable (at least several weeks at 5°C) and functionally active upon reconstitution into lipid membranes at high protein-to-lipid ratio required for solid-state NMR. The samples gave high-resolution (13)C and (15)N solid-state magic angle spinning NMR spectra, amenable to a detailed structural analysis. We believe that similar protocols can be adopted for challenging mammalian targets, which often resist characterization by other structural methods.
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Affiliation(s)
- Ying Fan
- Department of Physics, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
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17
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Petrovskaya LE, Shulga AA, Bocharova OV, Ermolyuk YS, Kryukova EA, Chupin VV, Blommers MJJ, Arseniev AS, Kirpichnikov MP. Expression of G-protein coupled receptors in Escherichia coli for structural studies. BIOCHEMISTRY (MOSCOW) 2010; 75:881-91. [PMID: 20673212 DOI: 10.1134/s0006297910070102] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
To elaborate a high-performance system for expression of genes of G-protein coupled receptors (GPCR), methods of direct and hybrid expression of 17 GPCR genes in Escherichia coli and selection of strains and bacteria cultivation conditions were investigated. It was established that expression of most of the target GPCR fused with the N-terminal fragment of OmpF or Mistic using media for autoinduction provides high output (up to 50 mg/liter).
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Affiliation(s)
- L E Petrovskaya
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.
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Tikhonova IG, Costanzi S. Unraveling the structure and function of G protein-coupled receptors through NMR spectroscopy. Curr Pharm Des 2010; 15:4003-16. [PMID: 20028318 DOI: 10.2174/138161209789824803] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
G protein-coupled receptors (GPCRs) are a large superfamily of signaling proteins expressed on the plasma membrane. They are involved in a wide range of physiological processes and, therefore, are exploited as drug targets in a multitude of therapeutic areas. In this extent, knowledge of structural and functional properties of GPCRs may greatly facilitate rational design of modulator compounds. Solution and solid-state nuclear magnetic resonance (NMR) spectroscopy represents a powerful method to gather atomistic insights into protein structure and dynamics. In spite of the difficulties inherent the solution of the structure of membrane proteins through NMR, these methods have been successfully applied, sometimes in combination with molecular modeling, to the determination of the structure of GPCR fragments, the mapping of receptor-ligand interactions, and the study of the conformational changes associated with the activation of the receptors. In this review, we provide a summary of the NMR contributions to the study of the structure and function of GPCRs, also in light of the published crystal structures.
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Affiliation(s)
- Irina G Tikhonova
- Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, DHHS, Bethesda, MD 20892, USA
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19
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Kim HJ, Howell SC, Van Horn WD, Jeon YH, Sanders CR. Recent Advances in the Application of Solution NMR Spectroscopy to Multi-Span Integral Membrane Proteins. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2009; 55:335-360. [PMID: 20161395 PMCID: PMC2782866 DOI: 10.1016/j.pnmrs.2009.07.002] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Affiliation(s)
- Hak Jun Kim
- Korea Polar Research Institute, Korea Ocean Research and Development Institute, Incheon, 406-840, Korea
| | - Stanley C. Howell
- Department of Biochemistry, Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232-8725, USA
| | - Wade D. Van Horn
- Department of Biochemistry, Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232-8725, USA
| | - Young Ho Jeon
- Center for Magnetic Resonance, Korea Basic Research Institute, Daejon, 305-333, Korea
| | - Charles R. Sanders
- Department of Biochemistry, Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232-8725, USA
- Corresponding Author: ; phone: 615-936-3756; fax: 615-936-2211
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Structure, dynamics and mapping of membrane-binding residues of micelle-bound antimicrobial peptides by natural abundance (13)C NMR spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1798:114-21. [PMID: 19682427 DOI: 10.1016/j.bbamem.2009.07.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 06/08/2009] [Accepted: 07/30/2009] [Indexed: 12/23/2022]
Abstract
Worldwide bacterial resistance to traditional antibiotics has drawn much research attention to naturally occurring antimicrobial peptides (AMPs) owing to their potential as alternative antimicrobials. Structural studies of AMPs are essential for an in-depth understanding of their activity, mechanism of action, and in guiding peptide design. Two-dimensional solution proton NMR spectroscopy has been the major tool. In this article, we describe the applications of natural abundance (13)C NMR spectroscopy that provides complementary information to 2D (1)H NMR. The correlation of (13)Calpha secondary shifts with both 3D structure and heteronuclear (15)N NOE values indicates that natural abundance carbon chemical shifts are useful probes for backbone structure and dynamics of membrane peptides. Using human LL-37-derived peptides (GF-17, KR-12, and RI-10), as well as amphibian antimicrobial and anticancer peptide aurein 1.2 and its analog LLAA, as models, we show that the cross peak intensity plots of 2D (1)H-(13)Calpha HSQC spectra versus residue number present a wave-like pattern (HSQC wave) where key hydrophobic residues of micelle-bound peptides are located in the troughs with weaker intensities, probably due to fast exchange between the free and bound forms. In all the cases, the identification of aromatic phenylalanines as a key membrane-binding residue is consistent with previous intermolecular Phe-lipid NOE observations. Furthermore, mutation of one of the key hydrophobic residues of KR-12 to Ala significantly reduced the antibacterial activity of the peptide mutants. These results illustrate that natural abundance heteronuclear-correlated NMR spectroscopy can be utilized to probe backbone structure and dynamics, and perhaps to map key membrane-binding residues of peptides in complex with micelles. (1)H-(13)Calpha HSQC wave, along with other NMR waves such as dipolar wave and chemical shift wave, offers novel insights into peptide-membrane interactions from different angles.
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21
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Dahmane T, Damian M, Mary S, Popot JL, Banères JL. Amphipol-assisted in vitro folding of G protein-coupled receptors. Biochemistry 2009; 48:6516-21. [PMID: 19534448 DOI: 10.1021/bi801729z] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
G protein-coupled receptors (GPCRs) regulate numerous physiological functions. The primary difficulty presented by their study in vitro is to obtain them in sufficient amounts under a functional and stable form. Escherichia coli is a host of choice for producing recombinant proteins for structural studies. However, the insertion of GPCRs into its plasma membrane usually results in bacterial death. An alternative approach consists of targeting recombinant receptors to inclusion bodies, where they accumulate without affecting bacterial growth, and then folding them in vitro. This approach, however, stumbles over the very low folding yields typically achieved, whether in detergent solutions or in detergent-lipid mixtures. Here, we show that synthetic polymers known as amphipols provide a highly efficient medium for folding GPCRs. Using a generic protocol, we have folded four class A GPCRs to their functional state, as evidenced by the binding of their respective ligands. This strategy thus appears to have the potential to be generalized to a large number of GPCRs. These data are also of interest from a more fundamental point of view: they indicate that the structural information stored in the sequence of these four receptors allows them to reach their correct three-dimensional structure in an environment that bears no similarity, beyond the amphiphilic character, to lipid bilayers.
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Affiliation(s)
- Tassadite Dahmane
- UMR 7099, CNRS and Université Paris-7, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005 Paris, France
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22
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Zou C, Naider F, Zerbe O. Biosynthesis and NMR-studies of a double transmembrane domain from the Y4 receptor, a human GPCR. JOURNAL OF BIOMOLECULAR NMR 2008; 42:257-269. [PMID: 18937032 DOI: 10.1007/s10858-008-9281-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 09/24/2008] [Accepted: 09/26/2008] [Indexed: 05/26/2023]
Abstract
The human Y4 receptor, a class A G-protein coupled receptor (GPCR) primarily targeted by the pancreatic polypeptide (PP), is involved in a large number of physiologically important functions. This paper investigates a Y4 receptor fragment (N-TM1-TM2) comprising the N-terminal domain, the first two transmembrane (TM) helices and the first extracellular loop followed by a (His)(6) tag, and addresses synthetic problems encountered when recombinantly producing such fragments from GPCRs in Escherichia coli. Rigorous purification and usage of the optimized detergent mixture 28 mM dodecylphosphocholine (DPC)/118 mM% 1-palmitoyl-2-hydroxy-sn-glycero-3-[phospho-rac-(1-glycerol)] (LPPG) resulted in high quality TROSY spectra indicating protein conformational homogeneity. Almost complete assignment of the backbone, including all TM residue resonances was obtained. Data on internal backbone dynamics revealed a high secondary structure content for N-TM1-TM2. Secondary chemical shifts and sequential amide proton nuclear Overhauser effects defined the TM helices. Interestingly, the properties of the N-terminal domain of this large fragment are highly similar to those determined on the isolated N-terminal domain in the presence of DPC micelles.
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Affiliation(s)
- Chao Zou
- Institute of Organic Chemistry, University of Zurich, Switzerland
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23
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Link AJ, Skretas G, Strauch EM, Chari NS, Georgiou G. Efficient production of membrane-integrated and detergent-soluble G protein-coupled receptors in Escherichia coli. Protein Sci 2008; 17:1857-63. [PMID: 18593817 PMCID: PMC2548370 DOI: 10.1110/ps.035980.108] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 06/19/2008] [Accepted: 06/20/2008] [Indexed: 10/21/2022]
Abstract
G protein-coupled receptors (GPCRs) are notoriously difficult to express, particularly in microbial systems. Using GPCR fusions with the green fluorescent protein (GFP), we conducted studies to identify bacterial host effector genes that result in a general and significant enhancement in the amount of membrane-integrated human GPCRs that can be produced in Escherichia coli. We show that coexpression of the membrane-bound AAA+ protease FtsH greatly enhances the expression yield of four different class I GPCRs, irrespective of the presence of GFP. Using this new expression system, we produced 0.5 and 2 mg/L of detergent-solubilized and purified full-length central cannabinoid receptor (CB1) and bradykinin receptor 2 (BR2) in shake flask cultures, respectively, two proteins that had previously eluded expression in microbial systems.
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MESH Headings
- ATP-Dependent Proteases/biosynthesis
- ATP-Dependent Proteases/genetics
- Cell Membrane/chemistry
- Cell Membrane/metabolism
- Detergents/chemistry
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Escherichia coli Proteins/biosynthesis
- Escherichia coli Proteins/genetics
- Green Fluorescent Proteins/biosynthesis
- Humans
- Protein Engineering
- Receptor, Bradykinin B2/biosynthesis
- Receptor, Bradykinin B2/chemistry
- Receptor, Bradykinin B2/isolation & purification
- Receptor, Cannabinoid, CB1/biosynthesis
- Receptor, Cannabinoid, CB1/chemistry
- Receptor, Cannabinoid, CB1/isolation & purification
- Receptors, G-Protein-Coupled/biosynthesis
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/isolation & purification
- Recombinant Fusion Proteins/biosynthesis
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/isolation & purification
- Solubility
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Affiliation(s)
- A James Link
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
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24
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Curtis-Fisk J, Spencer RM, Weliky DP. Isotopically labeled expression in E. coli, purification, and refolding of the full ectodomain of the influenza virus membrane fusion protein. Protein Expr Purif 2008; 61:212-9. [PMID: 18640277 DOI: 10.1016/j.pep.2008.06.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2008] [Revised: 06/17/2008] [Accepted: 06/17/2008] [Indexed: 11/29/2022]
Abstract
This paper describes methods to produce an isotopically labeled 23 kDa viral membrane protein with purified yield of 20 mg/L of Escherichia coli shake flask culture. This yield is sufficient for NMR structural studies and the protein production methods are simple, straightforward, and rapid and likely applicable to other recombinant membrane proteins expressed in E. coli. The target FHA2 protein is the full ectodomain construct of the influenza virus hemagglutinin protein which catalyzes fusion between the viral and the cellular endosomal membranes during infection. The high yield of FHA2 was achieved by: (1) initial growth in rich medium to A(600) approximately 8 followed by a switch to minimal medium and induction of protein expression; and (2) obtaining protein both from purification of the detergent-soluble lysate and from solubilization, purification, and refolding of inclusion bodies. The high cell density was achieved after optimization of pH, oxygenation, and carbon source and concentration, and the refolding protocol was optimized using circular dichroism spectroscopy. For a single residue of membrane-associated FHA2 that was obtained from purification and refolding of inclusion bodies, native conformation was verified by the (13)CO chemical shifts measured using solid-state nuclear magnetic resonance spectroscopy.
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Affiliation(s)
- Jaime Curtis-Fisk
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
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25
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Cohen LS, Arshava B, Estephan R, Englander J, Kim H, Hauser M, Zerbe O, Ceruso M, Becker JM, Naider F. Expression and biophysical analysis of two double-transmembrane domain-containing fragments from a yeast G protein-coupled receptor. Biopolymers 2008; 90:117-30. [DOI: 10.1002/bip.20950] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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26
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Musial-Siwek M, Kendall DA, Yeagle PL. Solution NMR of signal peptidase, a membrane protein. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1778:937-44. [PMID: 18177734 DOI: 10.1016/j.bbamem.2007.11.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Revised: 10/09/2007] [Accepted: 11/26/2007] [Indexed: 11/16/2022]
Abstract
Useful solution nuclear magnetic resonance (NMR) data can be obtained from full-length, enzymatically active type I signal peptidase (SPase I), an integral membrane protein, in detergent micelles. Signal peptidase has two transmembrane segments, a short cytoplasmic loop, and a 27-kD C-terminal catalytic domain. It is a critical component of protein transport systems, recognizing and cleaving amino-terminal signal peptides from preproteins during the final stage of their export. Its structure and interactions with the substrate are of considerable interest, but no three-dimensional structure of the whole protein has been reported. The structural analysis of intact membrane proteins has been challenging and only recently has significant progress been achieved using NMR to determine membrane protein structure. Here we employ NMR spectroscopy to study the structure of the full-length SPase I in dodecylphosphocholine detergent micelles. HSQC-TROSY spectra showed resonances corresponding to approximately 3/4 of the 324 residues in the protein. Some sequential assignments were obtained from the 3D HNCACB, 3D HNCA, and 3D HN(CO) TROSY spectra of uniformly 2H, 13C, 15N-labeled full-length SPase I. The assigned residues suggest that the observed spectrum is dominated by resonances arising from extramembraneous portions of the protein and that the transmembrane domain is largely absent from the spectra. Our work elucidates some of the challenges of solution NMR of large membrane proteins in detergent micelles as well as the future promise of these kinds of studies.
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Affiliation(s)
- Monika Musial-Siwek
- Department of Molecular and Cell Biology, The University of Connecticut, Storrs, CT 06269, USA
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27
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Tian C, Vanoye CG, Kang C, Welch RC, Kim HJ, George AL, Sanders CR. Preparation, functional characterization, and NMR studies of human KCNE1, a voltage-gated potassium channel accessory subunit associated with deafness and long QT syndrome. Biochemistry 2007; 46:11459-72. [PMID: 17892302 PMCID: PMC2565491 DOI: 10.1021/bi700705j] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
KCNE1, also known as minK, is a member of the KCNE family of membrane proteins that modulate the function of KCNQ1 and certain other voltage-gated potassium channels (KV). Mutations in human KCNE1 cause congenital deafness and congenital long QT syndrome, an inherited predisposition to potentially life-threatening cardiac arrhythmias. Although its modulation of KCNQ1 function has been extensively characterized, many questions remain regarding KCNE1's structure and location within the channel complex. In this study, KCNE1 was overexpressed in Escherichia coli and purified. Micellar solutions of the protein were then microinjected into Xenopus oocytes expressing KCNQ1 channels, followed by electrophysiological recordings aimed at testing whether recombinant KCNE1 can co-assemble with the channel. Nativelike modulation of channel properties was observed following injection of KCNE1 in lyso-myristoylphosphatidylglycerol (LMPG) micelles, indicating that KCNE1 is not irreversibly misfolded and that LMPG is able to act as a vehicle for delivering membrane proteins into the membranes of viable cells. 1H-15N TROSY NMR experiments indicated that LMPG micelles are well-suited for structural studies of KCNE1, leading to assignment of its backbone resonances and to relaxation studies. The chemical shift data confirmed that KCNE1's secondary structure includes several alpha-helices and demonstrated that its distal C-terminus is disordered. Surprisingly, for KCNE1 in LMPG micelles, there appears to be a break in alpha-helicity at sites 59-61, near the middle of the transmembrane segment, a feature that is accompanied by increased local backbone mobility. Given that this segment overlaps with sites 57-59, which are known to play a critical role in modulating KCNQ1 channel activation kinetics, this unusual structural feature likely has considerable functional relevance.
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Affiliation(s)
| | | | | | | | | | | | - Charles R. Sanders
- To whom correspondence should be addressed: E-mail: ; phone: 615−936−3756; fax: 615−936−2211
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28
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Kerman A, Ananthanarayanan VS. Conformation of a double-membrane-spanning fragment of a G protein-coupled receptor: Effects of hydrophobic environment and pH. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:1199-210. [PMID: 17337264 DOI: 10.1016/j.bbamem.2007.01.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Revised: 01/17/2007] [Accepted: 01/22/2007] [Indexed: 11/23/2022]
Abstract
Overcoming the problems associated with the expression, purification and in vitro handling of membrane proteins requires an understanding of the factors governing the folding and stability of such proteins in detergent solutions. As a sequel to our earlier report (Biochim. Biophys. Acta 1747(2005), 133-140), we describe an improved purification procedure and a detailed structural analysis of a fragment of the mu-opioid receptor ('TM2-3') that comprises the second and third transmembrane segments and the extracellular loop that connects them. Circular dichroism (CD) spectroscopy of TM2-3 in 2,2,2-trifluoroethanol gave a helical content similar to that predicted by published homology models, while spectra acquired in several detergents showed significantly lower helical contents. This indicates that this part of the mu-opioid receptor has an intrinsic propensity to be highly helical in membrane-like environments, but that in detergent solutions, this helical structure is not fully formed. Proteolysis of TM2-3 with trypsin showed that the helical portions of TM2 and TM3 are both shorter than their predicted lengths, indicating that helix-helix interactions in the full-length receptor are apparently important for stabilizing their conformation. Lengthening the alkyl chain of the detergent led to a small but significant increase in the helicity of TM2-3, suggesting that hydrophobic mismatch could play an important role in the stabilization of transmembrane helices by detergents. Protonation of aspartic acid residues in detergent-solubilized TM2-3 also caused a significant increase in helicity. Our results thus suggest that detergent alkyl chain-length and pH may influence membrane protein stability by modulating the stability of individual transmembrane segments.
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Affiliation(s)
- Aaron Kerman
- Department of Biochemistry and Biomedical Sciences, McMaster University, Health Sciences Centre, Room 4H25, 1200 Main St. W., Hamilton, Ontario, Canada L8N 3Z5
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29
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Neumoin A, Arshava B, Becker J, Zerbe O, Naider F. NMR studies in dodecylphosphocholine of a fragment containing the seventh transmembrane helix of a G-protein-coupled receptor from Saccharomyces cerevisiae. Biophys J 2007; 93:467-82. [PMID: 17449670 PMCID: PMC1896227 DOI: 10.1529/biophysj.106.103770] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The structure and dynamics of a large segment of Ste2p, the G-protein-coupled alpha-factor receptor from yeast, were studied in dodecylphosphocholine (DPC) micelles using solution NMR spectroscopy. We investigated the 73-residue peptide EL3-TM7-CT40 consisting of the third extracellular loop 3 (EL3), the seventh transmembrane helix (TM7), and 40 residues from the cytosolic C-terminal domain (CT40). The structure reveals the presence of an alpha-helix in the segment encompassing residues 10-30, which is perturbed around the internal Pro-24 residue. Root mean-square deviation values of individually superimposed helical segments 10-20 and 25-30 were 0.91 +/- 0.33 A and 0.76 +/- 0.37 A, respectively. 15N-relaxation and residual dipolar coupling data support a rather stable fold for the TM7 part of EL3-TM7-CT40, whereas the EL3 and CT40 segments are more flexible. Spin-label data indicate that the TM7 helix integrates into DPC micelles but is flexible around the internal Pro-24 site, exposing residues 22-26 to solution and reveal a second site of interaction with the micelle within a region comprising residues 43-58, which forms part of a less well-defined nascent helix. These findings are discussed in light of previous studies in organic-aqueous solvent systems.
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Affiliation(s)
- Alexey Neumoin
- Institute of Organic Chemistry, University of Zurich, Zurich, Switzerland
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30
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Synthesis of a Double Transmembrane Domain Fragment of Ste2p by Native Chemical Ligation. Int J Pept Res Ther 2007. [DOI: 10.1007/s10989-006-9076-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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32
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Korepanova A, Moore JD, Nguyen HB, Hua Y, Cross TA, Gao F. Expression of membrane proteins from Mycobacterium tuberculosis in Escherichia coli as fusions with maltose binding protein. Protein Expr Purif 2006; 53:24-30. [PMID: 17275326 PMCID: PMC2684689 DOI: 10.1016/j.pep.2006.11.022] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2006] [Revised: 11/22/2006] [Accepted: 11/22/2006] [Indexed: 10/23/2022]
Abstract
Sixteen of 22 low molecular weight integral membrane proteins from Mycobacterium tuberculosis with previously poor or undetectable levels of expression were expressed in Escherichia coli as fusions with both the maltose binding protein (MBP) and a His(8)-tag. Sixty-eight percent of targeted proteins were expressed in high yield (>30 mg/L) in soluble and/or inclusion body form. Thrombin cleavage of the MBP fusion protein was successful for 10 of 13 proteins expressed as soluble proteins and for three proteins expressed only as inclusion bodies. The use of autoinduction growth media increased yields over Luria-Bertani (LB) growth media in 75% of the expressed proteins. Expressing integral membrane proteins with yields suitable for structural studies from a set of previously low and non-expressing proteins proved highly successful upon attachment of the maltose binding protein as a fusion tag.
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Affiliation(s)
- A Korepanova
- Abbott Laboratories, Dept. R46Y, Bldg. AP10-LL8, 100 Abbott Park Road, Abbott Park, IL 60064-6098, USA
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33
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Sanders CR, Sönnichsen F. Solution NMR of membrane proteins: practice and challenges. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2006; 44 Spec No:S24-40. [PMID: 16826539 DOI: 10.1002/mrc.1816] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
This review focuses upon the application of solution NMR methods to multispan integral membrane proteins, particularly with respect to determination of global folds by this approach. Practical methods are described along with the special difficulties that confront the application of solution NMR to proteins that dwell in the netherworld of the lipid bilayer.
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Affiliation(s)
- Charles R Sanders
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232-8725, USA.
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34
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Sankararamakrishnan R. Recognition of GPCRs by Peptide Ligands and Membrane Compartments theory: Structural Studies of Endogenous Peptide Hormones in Membrane Environment. Biosci Rep 2006; 26:131-58. [PMID: 16773462 DOI: 10.1007/s10540-006-9014-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
One of the largest family of cell surface proteins, G-protein coupled receptors (GPCRs) regulate virtually all known physiological processes in mammals. With seven transmembrane segments, they respond to diverse range of extracellular stimuli and represent a major class of drug targets. Peptidergic GPCRs use endogenous peptides as ligands. To understand the mechanism of GPCR activation and rational drug design, knowledge of three-dimensional structure of receptor–ligand complex is important. The endogenous peptide hormones are often short, flexible and completely disordered in aqueous solution. According to “Membrane Compartments Theory”, the flexible peptide binds to the membrane in the first step before it recognizes its receptor and the membrane-induced conformation is postulated to bind to the receptor in the second step. Structures of several peptide hormones have been determined in membrane-mimetic medium. In these studies, micelles, reverse micelles and bicelles have been used to mimic the cell membrane environment. Recently, conformations of two peptide hormones have also been studied in receptor-bound form. Membrane environment induces stable secondary structures in flexible peptide ligands and membrane-induced peptide structures have been correlated with their bioactivity. Results of site-directed mutagenesis, spectroscopy and other experimental studies along with the conformations determined in membrane medium have been used to interpret the role of individual residues in the peptide ligand. Structural differences of membrane-bound peptides that belong to the same family but differ in selectivity are likely to explain the mechanism of receptor selectivity and specificity of the ligands. Knowledge of peptide 3D structures in membrane environment has potential applications in rational drug design.
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35
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Park SH, Prytulla S, De Angelis AA, Brown JM, Kiefer H, Opella SJ. High-resolution NMR spectroscopy of a GPCR in aligned bicelles. J Am Chem Soc 2006; 128:7402-3. [PMID: 16756269 PMCID: PMC3236030 DOI: 10.1021/ja0606632] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Solid-state NMR spectra with single-site resolution of CXCR1, a G protein-coupled receptor (GPCR), were obtained in magnetically aligned phospholipid bicelles. These results demonstrate that GPCRs in phospholipid bilayers are suitable samples for structure determination by solid-state NMR. The spectra also enable studies of drug-receptor interactions.
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Affiliation(s)
- Sang Ho Park
- Department of Chemistry and Biochemistry. University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0307, USA
| | - Stefan Prytulla
- m-phasys GmbH, Vor dem Kreuzberg 17, Tubingen 72070, Germany
| | - Anna A. De Angelis
- Department of Chemistry and Biochemistry. University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0307, USA
| | | | - Hans Kiefer
- m-phasys GmbH, Vor dem Kreuzberg 17, Tubingen 72070, Germany
| | - Stanley J. Opella
- Department of Chemistry and Biochemistry. University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0307, USA
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36
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Todokoro Y, Yumen I, Fukushima K, Kang SW, Park JS, Kohno T, Wakamatsu K, Akutsu H, Fujiwara T. Structure of tightly membrane-bound mastoparan-X, a G-protein-activating peptide, determined by solid-state NMR. Biophys J 2006; 91:1368-79. [PMID: 16714348 PMCID: PMC1518647 DOI: 10.1529/biophysj.106.082735] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The structure of mastoparan-X (MP-X), a G-protein activating peptide from wasp venom, in the state tightly bound to anionic phospholipid bilayers was determined by solid-state NMR spectroscopy. Carbon-13 and nitrogen-15 NMR signals of uniformly labeled MP-X were completely assigned by multidimensional intraresidue C-C, N-CalphaCbeta, and N-Calpha-C', and interresidue Calpha-CalphaCbeta, N-CalphaCbeta, and N-C'-Calpha correlation experiments. The backbone torsion angles were predicted from the chemical shifts of 13C', 13Calpha, 13Cbeta, and 15N signals with the aid of protein NMR database programs. In addition, two 13C-13C and three 13C-15N distances between backbone nuclei were precisely measured by rotational resonance and REDOR experiments, respectively. The backbone structure of MP-X was determined from the 26 dihedral angle restraints and five distances with an average root-mean-square deviation of 0.6 A. Peptide MP-X in the bilayer-bound state formed an amphiphilic alpha-helix for residues Trp3-Leu14 and adopted an extended conformation for Asn2. This membrane-bound conformation is discussed in relation to the peptide's activities to form pores in membranes and to activate G-proteins. This study demonstrates the power of multidimensional solid-state NMR of uniformly isotope-labeled molecules and distance measurements for determining the structures of peptides bound to lipid membranes.
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Affiliation(s)
- Yasuto Todokoro
- Institute for Protein Research, Osaka University, Suita, Japan
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Sánta-Csutor A, Mucsi Z, Finta Z, Gönczi C, Halász J, Csikós É, Hermecz I. Kinetic and Theoretical Studies of a Facile, One-Pot Preparation of a Spirocyclohexylindolinone Derivative. European J Org Chem 2006. [DOI: 10.1002/ejoc.200500798] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Zheng H, Zhao J, Sheng W, Xie XQ. A transmembrane helix-bundle from G-protein coupled receptor CB2: Biosynthesis, purification, and NMR characterization. Biopolymers 2006; 83:46-61. [PMID: 16634087 DOI: 10.1002/bip.20526] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The cannabinoid receptor subtype 2 (CB2) is a member of the G-protein coupled receptor (GPCR) superfamily. As the relationship between structure and function for this receptor remains poorly understood, the present study was undertaken to characterize the structure of a segment including the first and second transmembrane helix (TM1 and TM2) domains of CB2. To accomplish this, a transmembrane double-helix bundle from this region was expressed, purified, and characterized by NMR. Milligrams of this hydrophobic fragment of the receptor were biosynthesized using a fusion protein overexpression strategy and purified by affinity chromatography combined with reverse phase HPLC. Chemical and enzymatic cleavage methods were implemented to remove the fusion tag. The resultant recombinant protein samples were analyzed and confirmed by HPLC, mass spectrometry, and circular dichroism (CD). The CD analyses of HPLC-purified protein in solution and in DPC micelle preparations suggested predominant alpha-helical structures under both conditions. The 13C/15N double-labeled protein CB2(27-101) was further verified and analyzed by NMR spectroscopy. Sequential assignment was accomplished for more than 80% of residues. The 15N HSQC NMR results show a clear chemical shift dispersion of the amide nitrogen-proton correlation indicative of a pure double-labeled polypeptide molecule. The results suggest that this method is capable of generating transmembrane helical bundles from GPCRs in quantity and purity sufficient for NMR and other biophysical studies. Therefore, the biosynthesis of GPCR transmembrane helix bundles represents a satisfactory alternative strategy to obtain and assemble NMR structures from recombinant "building blocks."
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Affiliation(s)
- HaiAn Zheng
- Department of Pharmaceutical and Pharmacological Sciences, College of Pharmacy, University of Houston, Houston, TX, 77204-5037, USA
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Schwalbe H, Stilz HU, Kessler H. Editorial: NMR Spectroscopy of Biomacromolecules in Drug Discovery and Beyond. Chembiochem 2005. [DOI: 10.1002/cbic.200590029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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