1
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Fukuda N. Apparent diameter and cell density of yeast strains with different ploidy. Sci Rep 2023; 13:1513. [PMID: 36707648 PMCID: PMC9883461 DOI: 10.1038/s41598-023-28800-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 01/24/2023] [Indexed: 01/28/2023] Open
Abstract
Optical density at 600 nm (OD600) measurements are routinely and quickly taken to estimate cell density in cultivation and to track cell growth. The yeast Saccharomyces cerevisiae is one of the microorganisms most used in industry, and the OD600 values are frequently adopted as the indicator of yeast cell density, according to the Beer-Lambert law. Because the OD600 value is based on turbidity measurement, the Beer-Lambert law can be applied only for microbial cultivation with low cell densities. The proportionality constants strongly depend on several parameters such as cell size. Typically, yeast strains are categorized into haploids and diploids. It is well known that cell size of diploid yeasts is larger than haploid cells. Additionally, polyploid (especially triploid and tetraploid) yeast cells are also employed in several human-activities such as bread-making and lager-brewing. As a matter of fact, there is almost no attention paid to the difference in the proportionality constants depending on the yeast ploidy. This study presents information for cell size of haploid, diploid, triploid, and tetraploid yeasts with isogenic background, and describes their proportionality constants (k) corresponding to the molar extinction coefficient (ε) in the Beer-Lambert law. Importantly, it was found that the constants are inversely proportional to apparent cell diameters estimated by flow cytometric analysis. Although each cell property highly depends on genetic and environmental factors, a set of results obtained from yeast strains with different ploidy in the current study would serve as a major reference source for researchers and technical experts.
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Affiliation(s)
- Nobuo Fukuda
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka, 563-8577, Japan.
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2
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Karki R, Rimal S, Rieth MD. Predicted N-terminal N-linked glycosylation sites may underlie membrane protein expression patterns in Saccharomyces cerevisiae. Yeast 2021; 38:497-506. [PMID: 34182612 DOI: 10.1002/yea.3657] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 06/15/2021] [Accepted: 06/17/2021] [Indexed: 12/14/2022] Open
Abstract
N-linked glycosylation is one type of posttranslational modification that proteins undergo during expression. The following describes the effects of N-linked glycosylation on high-level membrane protein expression in yeast with an emphasis on Saccharomyces cerevisiae. N-linked glycosylation is highlighted here as an important consideration when preparing membrane protein gene constructs for expression in S. cerevisiae, which continues to be used as a workhorse in both research and industrial applications. Non-native N-linked glycosylation commonly occurs during the heterologous expression of mammalian proteins in many yeast species which can have important immunological consequences when used in the production of biotherapeutic proteins or peptides. Further, non-native N-linked glycosylation can lead to improper protein folding and premature degradation, which can impede high-level expression yields and hinder downstream analysis. Multiple strategies are presented in this article, which suggest different methods that can be implemented to circumvent the unwanted consequences of N-linked glycosylation during the expression process. These considerations may have long-term benefits for high-level protein production in S. cerevisiae across a broad spectrum of expression targets with special emphasis placed on G-protein coupled receptors, one of the largest families of membrane proteins.
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Affiliation(s)
- Rashmi Karki
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Swechha Rimal
- Department of Chemistry, Southern Illinois University Edwardsville, Edwardsville, Illinois, USA
| | - Monica D Rieth
- Department of Chemistry, Southern Illinois University Edwardsville, Edwardsville, Illinois, USA
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3
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Dilworth MV, Findlay HE, Booth PJ. Detergent-free purification and reconstitution of functional human serotonin transporter (SERT) using diisobutylene maleic acid (DIBMA) copolymer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183602. [PMID: 33744253 PMCID: PMC8111416 DOI: 10.1016/j.bbamem.2021.183602] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 12/17/2022]
Abstract
Structure and function analysis of human membrane proteins in lipid bilayer environments is acutely lacking despite the fundame1ntal cellular importance of these proteins and their dominance of drug targets. An underlying reason is that detailed study usually requires a potentially destabilising detergent purification of the proteins from their host membranes prior to subsequent reconstitution in a membrane mimic; a situation that is exacerbated for human membrane proteins due to the inherent difficulties in overexpressing suitable quantities of the proteins. We advance the promising styrene maleic acid polymer (SMA) extraction approach to introduce a detergent-free method of obtaining stable, functional human membrane transporters in bilayer nanodiscs directly from yeast cells. We purify the human serotonin transporter (hSERT) following overexpression in Pichia pastoris using diisobutylene maleic acid (DIBMA) as a superior method to traditional detergents or the more established styrene maleic acid polymer. hSERT plays a pivotal role in neurotransmitter regulation being responsible for the transport of the neurotransmitter 5-hydroxytryptamine (5-HT or serotonin). It is representative of the neurotransmitter sodium symporter (NSS) family, whose importance is underscored by the numerous diseases attributed to their malfunction. We gain insight into hSERT activity through an in vitro transport assay and find that DIBMA extraction improves the thermostability and activity of hSERT over the conventional detergent method. The non-aromatic amphipathic polymer DIBMA can be successfully employed to purify human membrane proteins. DIBMA solubilisation of hSERT from yeast membranes and resultant nanodisc thermostability is comparable to SMA. DIBMA and SMA encapsulated hSERT lipid-nanodiscs exhibit higher binding activity than hSERT DDMCHS micelles. Proteoliposomes reconstituted with hSERT-DIBMALPs possess higher transport activity than comparable DDMCHS reconstitutions.
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Affiliation(s)
- Marvin V Dilworth
- Department of Chemistry, King's College London, London SE1 1DB, United Kingdom.
| | - Heather E Findlay
- Department of Chemistry, King's College London, London SE1 1DB, United Kingdom.
| | - Paula J Booth
- Department of Chemistry, King's College London, London SE1 1DB, United Kingdom.
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4
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The Specificity of Downstream Signaling for A 1 and A 2AR Does Not Depend on the C-Terminus, Despite the Importance of This Domain in Downstream Signaling Strength. Biomedicines 2020; 8:biomedicines8120603. [PMID: 33322210 PMCID: PMC7764039 DOI: 10.3390/biomedicines8120603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/07/2020] [Accepted: 12/09/2020] [Indexed: 11/17/2022] Open
Abstract
Recent efforts to determine the high-resolution crystal structures for the adenosine receptors (A1R and A2AR) have utilized modifications to the native receptors in order to facilitate receptor crystallization and structure determination. One common modification is a truncation of the unstructured C-terminus, which has been utilized for all the adenosine receptor crystal structures obtained to date. Ligand binding for this truncated receptor has been shown to be similar to full-length receptor for A2AR. However, the C-terminus has been identified as a location for protein-protein interactions that may be critical for the physiological function of these important drug targets. We show that variants with A2AR C-terminal truncations lacked cAMP-linked signaling compared to the full-length receptor constructs transfected into mammalian cells (HEK-293). In addition, we show that in a humanized yeast system, the absence of the full-length C-terminus affected downstream signaling using a yeast MAPK response-based fluorescence assay, though full-length receptors showed native-like G-protein coupling. To further study the G protein coupling, we used this humanized yeast platform to explore coupling to human-yeast G-protein chimeras in a cellular context. Although the C-terminus was essential for Gα protein-associated signaling, chimeras of A1R with a C-terminus of A2AR coupled to the A1R-specific Gα (i.e., Gαi1 versus Gαs). This surprising result suggests that the C-terminus is important in the signaling strength, but not specificity, of the Gα protein interaction. This result has further implications in drug discovery, both in enabling the experimental use of chimeras for ligand design, and in the cautious interpretation of structure-based drug design using truncated receptors.
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5
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Jain AR, Britton ZT, Markwalter CE, Robinson AS. Improved ligand-binding- and signaling-competent human NK2R yields in yeast using a chimera with the rat NK2R C-terminus enable NK2R-G protein signaling platform. Protein Eng Des Sel 2020; 32:459-469. [PMID: 32400863 DOI: 10.1093/protein/gzaa009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 03/09/2020] [Accepted: 04/16/2020] [Indexed: 02/07/2023] Open
Abstract
The tachykinin 2 receptor (NK2R) plays critical roles in gastrointestinal, respiratory and mental disorders and is a well-recognized target for therapeutic intervention. To date, therapeutics targeting NK2R have failed to meet regulatory agency approval due in large part to the limited characterization of the receptor-ligand interaction and downstream signaling. Herein, we report a protein engineering strategy to improve ligand-binding- and signaling-competent human NK2R that enables a yeast-based NK2R signaling platform by creating chimeras utilizing sequences from rat NK2R. We demonstrate that NK2R chimeras incorporating the rat NK2R C-terminus exhibited improved ligand-binding yields and downstream signaling in engineered yeast strains and mammalian cells, where observed yields were better than 4-fold over wild type. This work builds on our previous studies that suggest exchanging the C-termini of related and well-expressed family members may be a general protein engineering strategy to overcome limitations to ligand-binding and signaling-competent G protein-coupled receptor yields in yeast. We expect these efforts to result in NK2R drug candidates with better characterized signaling properties.
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Affiliation(s)
- Abhinav R Jain
- Department of Chemical and Biomolecular Engineering, Tulane University, 6823 St Charles Ave, New Orleans, LA, 70118, USA
| | - Zachary T Britton
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy St, Newark, DE, 19716, USA.,AstraZeneca, Antibody Discovery and Protein Engineering, Gaithersburg, MD 20878, USA
| | - Chester E Markwalter
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy St, Newark, DE, 19716, USA.,Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Anne S Robinson
- Department of Chemical and Biomolecular Engineering, Tulane University, 6823 St Charles Ave, New Orleans, LA, 70118, USA.,Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy St, Newark, DE, 19716, USA.,Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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6
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Jain AR, Robinson AS. Functional Expression of Adenosine A 3 Receptor in Yeast Utilizing a Chimera with the A 2AR C-Terminus. Int J Mol Sci 2020; 21:E4547. [PMID: 32604732 PMCID: PMC7352405 DOI: 10.3390/ijms21124547] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 06/21/2020] [Accepted: 06/24/2020] [Indexed: 11/26/2022] Open
Abstract
The adenosine A3 receptor (A3R) is the only adenosine receptor subtype to be overexpressed in inflammatory and cancer cells and therefore is considered a novel and promising therapeutic target for inflammatory diseases and cancer. Heterologous expression of A3R at levels to allow biophysical characterization is a major bottleneck in structure-guided drug discovery efforts. Here, we apply protein engineering using chimeric receptors to improve expression and activity in yeast. Previously we had reported improved expression and trafficking of the chimeric A1R variant using a similar approach. In this report, we constructed chimeric A3/A2AR comprising the N-terminus and transmembrane domains from A3R (residues 1-284) and the cytoplasmic C-terminus of the A2AR (residues 291-412). The chimeric receptor showed approximately 2-fold improved expression with a 2-fold decreased unfolded protein response when compared to wild type A3R. Moreover, by varying culture conditions such as initial cell density and induction temperature a further 1.7-fold increase in total receptor yields was obtained. We observed native-like coupling of the chimeric receptor to Gai-Gpa1 in engineered yeast strains, activating the downstream, modified MAPK pathway. This strategy of utilizing chimeric receptor variants in yeast thus provides an exciting opportunity to improve expression and activity of "difficult-to-express" receptors, expanding the opportunity for utilizing yeast in drug discovery.
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Affiliation(s)
- Abhinav R. Jain
- Department of Chemical and Biomolecular Engineering, Tulane University, 6823 St Charles Ave, New Orleans, LA 70118, USA;
| | - Anne S. Robinson
- Department of Chemical and Biomolecular Engineering, Tulane University, 6823 St Charles Ave, New Orleans, LA 70118, USA;
- Department of Chemical Engineering, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213, USA
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7
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Jain AR, Stradley SH, Robinson AS. The A2aR C-terminus provides improved total and active expression yields for adenosine receptor chimeras. AIChE J 2018. [DOI: 10.1002/aic.16398] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Abhinav R. Jain
- Dept. of Chemical and Biomolecular Engineering; Tulane University; New Orleans LA 70118
| | - Steven H. Stradley
- Dept. of Chemical and Biomolecular Engineering; Tulane University; New Orleans LA 70118
| | - Anne S. Robinson
- Dept. of Chemical and Biomolecular Engineering; Tulane University; New Orleans LA 70118
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8
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Schonenbach NS, Rieth MD, Han S, O'Malley MA. Adenosine A2a receptors form distinct oligomers in protein detergent complexes. FEBS Lett 2016; 590:3295-306. [PMID: 27543907 DOI: 10.1002/1873-3468.12367] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Revised: 08/10/2016] [Accepted: 08/15/2016] [Indexed: 12/12/2022]
Abstract
The human adenosine A2a receptor (A2aR) tunes its function by forming homo-oligomers and hetero-oligomers with other G protein-coupled receptors, but the biophysical characterization of these oligomeric species is limited. Here, we show that upon reconstitution into an optimized mixed micelle system, and purification via an antagonist affinity column, full-length A2aR exists as a distribution of oligomers. We isolated the dimer population from the other oligomers via size exclusion chromatography and showed that it is stable upon dilution, thus supporting the hypotheses that the A2aR dimer has a defined structure and function. This study presents a crucial enabling step to a detailed biophysical characterization of A2aR homodimers.
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Affiliation(s)
- Nicole S Schonenbach
- Department of Chemical Engineering, University of California Santa Barbara, CA, USA
| | - Monica D Rieth
- Department of Chemical Engineering, University of California Santa Barbara, CA, USA
| | - Songi Han
- Department of Chemical Engineering, University of California Santa Barbara, CA, USA.,Department of Chemistry and Biochemistry, University of California Santa Barbara, CA, USA
| | - Michelle A O'Malley
- Department of Chemical Engineering, University of California Santa Barbara, CA, USA.
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9
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Van Zyl JHD, Den Haan R, Van Zyl WH. Overexpression of native Saccharomyces cerevisiae ER-to-Golgi SNARE genes increased heterologous cellulase secretion. Appl Microbiol Biotechnol 2015; 100:505-18. [PMID: 26450509 DOI: 10.1007/s00253-015-7022-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 08/14/2015] [Accepted: 09/05/2015] [Indexed: 12/30/2022]
Abstract
Soluble N-ethylmaleimide-sensitive factor attachment receptor proteins (SNAREs) are essential components of the yeast protein-trafficking machinery and are required at the majority of membrane fusion events in the cell, where they facilitate SNARE-mediated fusion between the protein transport vesicles, the various membrane-enclosed organelles and, ultimately, the plasma membrane. We have demonstrated an increase in secretory titers for the Talaromyces emersonii Cel7A (Te-Cel7A, a cellobiohydrolase) and the Saccharomycopsis fibuligera Cel3A (Sf-Cel3A, a β-glucosidase) expressed in Saccharomyces cerevisiae through single and co-overexpression of some of the endoplasmic reticulum (ER)-to-Golgi SNAREs (BOS1, BET1, SEC22 and SED5). Overexpression of SED5 yielded the biggest improvements for both of the cellulolytic reporter proteins tested, with maximum increases in extracellular enzyme activity of 22 % for the Sf-Cel3A and 68 % for the Te-Cel7A. Co-overexpression of the ER-to-Golgi SNAREs yielded proportionately smaller increases for the Te-Cel7A (46 %), with the Sf-Cel3A yielding no improvement. Co-overexpression of the most promising exocytic SNARE components identified in literature for secretory enhancement of the cellulolytic proteins tested (SSO1 for Sf-Cel3A and SNC1 for Te-Cel7A) with the most effective ER-to-Golgi SNARE components identified in this study (SED5 for both Sf-Cel3A and Te-Cel7A) yielded variable results, with Sf-Cel3A improved by 131 % and Te-Cel7A yielding no improvement. Improvements were largely independent of gene dosage as all strains only integrated single additional SNARE gene copies, with episomal variance between the most improved strains shown to be insignificant. This study has added further credence to the notion that SNARE proteins fulfil an essential role within a larger cascade of secretory machinery components that could contribute significantly to future improvements to S. cerevisiae as protein production host.
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Affiliation(s)
- John Henry D Van Zyl
- Department of Microbiology, Stellenbosch University, Stellenbosch, 7602, South Africa
| | - Riaan Den Haan
- Department of Biotechnology, University of the Western Cape, Bellville, 7530, South Africa
| | - Willem H Van Zyl
- Department of Microbiology, Stellenbosch University, Stellenbosch, 7602, South Africa.
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10
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Naranjo AN, Chevalier A, Cousins GD, Ayettey E, McCusker EC, Wenk C, Robinson AS. Conserved disulfide bond is not essential for the adenosine A2A receptor: Extracellular cysteines influence receptor distribution within the cell and ligand-binding recognition. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1848:603-14. [PMID: 25445670 PMCID: PMC4565196 DOI: 10.1016/j.bbamem.2014.11.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Revised: 10/22/2014] [Accepted: 11/10/2014] [Indexed: 11/16/2022]
Abstract
G protein-coupled receptors (GPCRs) are integral membrane proteins involved in cellular signaling and constitute major drug targets. Despite their importance, the relationship between structure and function of these receptors is not well understood. In this study, the role of extracellular disulfide bonds on the trafficking and ligand-binding activity of the human A2A adenosine receptor was examined. To this end, cysteine-to-alanine mutations were conducted to replace individual and both cysteines in three disulfide bonds present in the first two extracellular loops. Although none of the disulfide bonds were essential for the formation of plasma membrane-localized active GPCR, loss of the disulfide bonds led to changes in the distribution of the receptor within the cell and changes in the ligand-binding affinity. These results indicate that in contrast to many class A GPCRs, the extracellular disulfide bonds of the A2A receptor are not essential, but can modulate the ligand-binding activity, by either changing the conformation of the extracellular loops or perturbing the interactions of the transmembrane domains.
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Affiliation(s)
- Andrea N Naranjo
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, DE 19716, USA.
| | - Amy Chevalier
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, DE 19716, USA.
| | - Gregory D Cousins
- Department of Computer Science, Tulane University, 6823 St. Charles Ave, New Orleans, LA 70118, USA
| | - Esther Ayettey
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, DE 19716, USA
| | - Emily C McCusker
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, DE 19716, USA.
| | - Carola Wenk
- Department of Computer Science, Tulane University, 6823 St. Charles Ave, New Orleans, LA 70118, USA.
| | - Anne S Robinson
- Department of Chemical and Biomolecular Engineering, Tulane University, 300 Lindy Boggs Laboratory, 6823 St. Charles Ave, New Orleans, LA 70118, USA; Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, DE 19716, USA.
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11
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Blocker KM, Britton ZT, Naranjo AN, McNeely PM, Young CL, Robinson AS. Recombinant G Protein-Coupled Receptor Expression in Saccharomyces cerevisiae for Protein Characterization. Methods Enzymol 2015; 556:165-83. [DOI: 10.1016/bs.mie.2014.12.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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12
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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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13
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Tyo KEJ, Liu Z, Petranovic D, Nielsen J. Imbalance of heterologous protein folding and disulfide bond formation rates yields runaway oxidative stress. BMC Biol 2012; 10:16. [PMID: 22380681 PMCID: PMC3310788 DOI: 10.1186/1741-7007-10-16] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 03/01/2012] [Indexed: 01/17/2023] Open
Abstract
Background The protein secretory pathway must process a wide assortment of native proteins for eukaryotic cells to function. As well, recombinant protein secretion is used extensively to produce many biologics and industrial enzymes. Therefore, secretory pathway dysfunction can be highly detrimental to the cell and can drastically inhibit product titers in biochemical production. Because the secretory pathway is a highly-integrated, multi-organelle system, dysfunction can happen at many levels and dissecting the root cause can be challenging. In this study, we apply a systems biology approach to analyze secretory pathway dysfunctions resulting from heterologous production of a small protein (insulin precursor) or a larger protein (α-amylase). Results HAC1-dependent and independent dysfunctions and cellular responses were apparent across multiple datasets. In particular, processes involving (a) degradation of protein/recycling amino acids, (b) overall transcription/translation repression, and (c) oxidative stress were broadly associated with secretory stress. Conclusions Apparent runaway oxidative stress due to radical production observed here and elsewhere can be explained by a futile cycle of disulfide formation and breaking that consumes reduced glutathione and produces reactive oxygen species. The futile cycle is dominating when protein folding rates are low relative to disulfide bond formation rates. While not strictly conclusive with the present data, this insight does provide a molecular interpretation to an, until now, largely empirical understanding of optimizing heterologous protein secretion. This molecular insight has direct implications on engineering a broad range of recombinant proteins for secretion and provides potential hypotheses for the root causes of several secretory-associated diseases.
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Affiliation(s)
- Keith E J Tyo
- Department of Chemical and Biological Engineering, Chalmers University of Technology, Kemivägen 10, SE-41296 Göteborg, Sweden
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14
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O'Malley MA, Helgeson ME, Wagner NJ, Robinson AS. Toward rational design of protein detergent complexes: determinants of mixed micelles that are critical for the in vitro stabilization of a G-protein coupled receptor. Biophys J 2012; 101:1938-48. [PMID: 22004748 DOI: 10.1016/j.bpj.2011.09.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Revised: 09/06/2011] [Accepted: 09/12/2011] [Indexed: 01/02/2023] Open
Abstract
Although reconstitution of membrane proteins within protein detergent complexes is often used to enable their structural or biophysical characterization, it is unclear how one should rationally choose the appropriate micellar environment to preserve native protein folding. Here, we investigated model mixed micelles consisting of a nonionic glucosylated alkane surfactant from the maltoside and thiomaltoside families, bile salt surfactant, and the steryl derivative cholesteryl hemisuccinate. We correlated several key attributes of these micelles with the in vitro ligand-binding activity of hA(2)aR in these systems. Through small-angle neutron scattering and radioligand-binding analysis, we found several key aspects of mixed micellar systems that preserve the activity of hA(2)aR, including a critical amount of cholesteryl hemisuccinate per micelle, and an optimal hydrophobic thickness of the micelle that is analogous to the thickness of native mammalian bilayers. These features are closely linked to the headgroup chemistry of the surfactant and the hydrocarbon chain length, which influence both the morphology and composition of resulting micelles. This study should serve as a general guide for selecting the appropriate mixed surfactant systems to stabilize membrane proteins for biophysical analysis.
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Affiliation(s)
- Michelle A O'Malley
- Department of Chemical Engineering, University of Delaware, Newark, Delaware, USA
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15
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Berger C, Montag C, Berndt S, Huster D. Optimization of Escherichia coli cultivation methods for high yield neuropeptide Y receptor type 2 production. Protein Expr Purif 2011; 76:25-35. [DOI: 10.1016/j.pep.2010.10.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Revised: 10/20/2010] [Accepted: 10/27/2010] [Indexed: 12/11/2022]
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16
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Berger C, Ho JTC, Kimura T, Hess S, Gawrisch K, Yeliseev A. Preparation of stable isotope-labeled peripheral cannabinoid receptor CB2 by bacterial fermentation. Protein Expr Purif 2010; 70:236-47. [PMID: 20044006 DOI: 10.1016/j.pep.2009.12.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 12/18/2009] [Accepted: 12/23/2009] [Indexed: 12/23/2022]
Abstract
We developed a bacterial fermentation protocol for production of a stable isotope-labeled cannabinoid receptor CB2 for subsequent structural studies of this protein by nuclear magnetic resonance spectroscopy. The human peripheral cannabinoid receptor was expressed in Escherichia coli as a fusion with maltose binding protein and two affinity tags. The fermentation was performed in defined media comprised of mineral salts, glucose and (15)N(2)-L-tryptophan to afford incorporation of the labeled amino acid into the protein. Medium, growth and expression conditions were optimized so that the fermentation process produced about 2mg of purified, labeled CB2/L of culture medium. By performing a mass spectroscopic characterization of the purified CB2, we determined that one of the two (15)N atoms in tryptophan was incorporated into the recombinant protein. NMR analysis of (15)N chemical shifts strongly suggests that the (15)N atoms are located in Trp-indole rings. Importantly, analysis of the peptides derived from the CNBr cleavage of the purified protein confirmed a minimum of 95% incorporation of the labeled tryptophan into the CB2 sequence. The labeled CB2, purified and reconstituted into liposomes at a protein-to-lipid molar ratio of 1:500, was functional as confirmed by activation of cognate G proteins in an in vitro coupled assay. To our knowledge, this is the first reported production of a biologically active, stable isotope-labeled G protein-coupled receptor by bacterial fermentation.
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Affiliation(s)
- Christian Berger
- Institute for Biochemistry and Biotechnology, Martin-Luther University, Halle-Wittenberg, Kurt-Mothes-Str., 3, 06120 Halle, Germany
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Koth CMM, Payandeh J. Strategies for the cloning and expression of membrane proteins. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2009; 76:43-86. [PMID: 20663478 DOI: 10.1016/s1876-1623(08)76002-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Despite the determination of thousands of high-resolution structures of soluble proteins, many features of integral membrane proteins render them difficult targets for the structural biologist. Among these, the most important challenge is in expressing sufficient quantities of active protein to support downstream purification and structure determination efforts. Over 190 unique membrane protein structures have now been solved, and noticeable trends in successful expression strategies are beginning to emerge. A number of groups have also explored high-throughput (HTP) methods for membrane protein expression, with varying degrees of success. Here we review the current state of expressing membrane proteins for functional and structural studies. We first survey successful methods that have already yielded levels of membrane protein expression sufficient for structure determination. HTP methods are also examined since these aim to explore large numbers of targets and can predict reasonable starting points for many membrane proteins. Since HTP techniques may fail, particularly for certain classes of eukaryotic targets, detailed strategies for the expression of two prominent classes of eukaryotic protein families, G-protein-coupled receptors and ion channels, are also summarized.
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Affiliation(s)
- Christopher M M Koth
- Department of Structural Biology, Genentech, South San Francisco, California 94080, USA
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Huang D, Gore PR, Shusta EV. Increasing yeast secretion of heterologous proteins by regulating expression rates and post-secretory loss. Biotechnol Bioeng 2008; 101:1264-75. [DOI: 10.1002/bit.22019] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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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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Hamilton BS, Brede Y, Tolbert TJ. Expression and characterization of human glycosylated interleukin-1 receptor antagonist in Pichia pastoris. Protein Expr Purif 2008; 59:64-8. [DOI: 10.1016/j.pep.2008.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Revised: 01/07/2008] [Accepted: 01/10/2008] [Indexed: 01/14/2023]
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McCusker EC, Bane SE, O'Malley MA, Robinson AS. Heterologous GPCR expression: a bottleneck to obtaining crystal structures. Biotechnol Prog 2007; 23:540-7. [PMID: 17397185 DOI: 10.1021/bp060349b] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
G protein-coupled receptors (GPCRs) are an important, medically relevant class of integral membrane proteins. Laboratories throughout all disciplines of science devote time and energy into developing practical methods for the discovery, isolation, and characterization of these proteins. Since the crystal structure of rhodopsin was solved 6 years ago, the race to determine high-resolution structures of more GPCRs has gained momentum. Since certain GPCRs are currently produced at sufficient levels for X-ray crystallography trials, it is speculated that heterologous expression of GPCRs may no longer be a bottleneck in obtaining crystal structures. This Review focuses on the current approaches in heterologous expression of GPCRs and explores the problems associated with obtaining crystal structures from GPCRs expressed in different systems. Although milligram amounts of certain GPCRs are attainable, the majority of GPCRs are still either produced at very low levels or not at all. Developing reliable expression techniques for GPCRs is still a major priority for the structural characterization of GPCRs.
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Affiliation(s)
- Emily C McCusker
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19711, USA
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