1
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Reeves PJ. Expression systems for bovine rhodopsin: a review of the progress made in the Khorana laboratory. Biophys Rev 2023; 15:93-101. [PMID: 36909956 PMCID: PMC9995624 DOI: 10.1007/s12551-022-01037-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 12/11/2022] [Indexed: 01/09/2023] Open
Abstract
Here I will review the development of gene expression systems for production of bovine rhodopsin in the Khorana laboratory with particular focus on stable mammalian cell lines made using human embryonic kidney cells (HEK293S). The synthesis of a gene encoding bovine rhodopsin was completed in 1986. This gene was expertly designed with the built-in capacity for DNA duplex cassette replacement mutagenesis which made site-directed mutagenesis relatively straightforward. Intense effort was expended over several years in order to identify a gene expression system capable of producing rhodopsin in milligram amounts as required for biophysical studies. Mammalian expression systems, both transient and stable, were found to be the most favourable based on several criteria including receptor expression levels, correct folding and post translational processing, and capacity for purification of fully functional receptor. Transient expression using COS-1 cells was preferred for routine small-scale production of rhodopsin mutants, while HEK293S stable cell lines were used when milligram amounts of rhodopsin mutants were needed; for example, when conducting NMR studies.
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Affiliation(s)
- Philip J Reeves
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ Essex UK
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2
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Selikhanov G, Atamas A, Yukhimchuk D, Fufina T, Vasilieva L, Gabdulkhakov A. Stabilization of Cereibacter sphaeroides Photosynthetic Reaction Center by the Introduction of Disulfide Bonds. MEMBRANES 2023; 13:154. [PMID: 36837657 PMCID: PMC9967408 DOI: 10.3390/membranes13020154] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/19/2023] [Accepted: 01/23/2023] [Indexed: 06/18/2023]
Abstract
The photosynthetic reaction center of the purple nonsulfur bacterium Cereibacter sphaeroides is a useful model for the study of mechanisms of photoinduced electron transfer and a promising component for photo-bio-electrocatalytic systems. The basic research and technological applications of this membrane pigment-protein complex require effective approaches to increase its structural stability. In this work, a rational design approach to genetically modify the reaction centers by introducing disulfide bonds is used. This resulted in significantly increasing the thermal stability of some of the mutant pigment-protein complexes. The formation of the S-S bonds was confirmed by X-ray crystallography as well as SDS-PAGE, and the optical properties of the reaction centers were studied. The genetically modified reaction centers presented here preserved their ability for photochemical charge separation and could be of interest for basic science and biotechnology.
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Affiliation(s)
- Georgii Selikhanov
- Institute of Protein Research, Russian Academy of Sciences, Institutskaya 4, 142290 Pushchino, Moscow Region, Russia
- Federal Research Center Pushchino Scientific Center for Biological Research PSCBR, Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya 2, 142290 Pushchino, Moscow Region, Russia
| | - Anastasia Atamas
- Institute of Protein Research, Russian Academy of Sciences, Institutskaya 4, 142290 Pushchino, Moscow Region, Russia
| | - Diana Yukhimchuk
- Institute of Protein Research, Russian Academy of Sciences, Institutskaya 4, 142290 Pushchino, Moscow Region, Russia
| | - Tatiana Fufina
- Federal Research Center Pushchino Scientific Center for Biological Research PSCBR, Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya 2, 142290 Pushchino, Moscow Region, Russia
| | - Lyudmila Vasilieva
- Federal Research Center Pushchino Scientific Center for Biological Research PSCBR, Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya 2, 142290 Pushchino, Moscow Region, Russia
| | - Azat Gabdulkhakov
- Institute of Protein Research, Russian Academy of Sciences, Institutskaya 4, 142290 Pushchino, Moscow Region, Russia
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3
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Dmitrieva DA, Kotova TV, Safronova NA, Sadova AA, Dashevskii DE, Mishin AV. Protein Design Strategies for the Structural–Functional Studies of G Protein-Coupled Receptors. BIOCHEMISTRY (MOSCOW) 2023; 88:S192-S226. [PMID: 37069121 DOI: 10.1134/s0006297923140110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
G protein-coupled receptors (GPCRs) are an important family of membrane proteins responsible for many physiological functions in human body. High resolution GPCR structures are required to understand their molecular mechanisms and perform rational drug design, as GPCRs play a crucial role in a variety of diseases. That is difficult to obtain for the wild-type proteins because of their low stability. In this review, we discuss how this problem can be solved by using protein design strategies developed to obtain homogeneous stabilized GPCR samples for crystallization and cryoelectron microscopy.
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Affiliation(s)
- Daria A Dmitrieva
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia
| | - Tatiana V Kotova
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia
| | - Nadezda A Safronova
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia
| | - Alexandra A Sadova
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia
| | - Dmitrii E Dashevskii
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia
| | - Alexey V Mishin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia.
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4
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de Grip WJ, Ganapathy S. Rhodopsins: An Excitingly Versatile Protein Species for Research, Development and Creative Engineering. Front Chem 2022; 10:879609. [PMID: 35815212 PMCID: PMC9257189 DOI: 10.3389/fchem.2022.879609] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 05/16/2022] [Indexed: 01/17/2023] Open
Abstract
The first member and eponym of the rhodopsin family was identified in the 1930s as the visual pigment of the rod photoreceptor cell in the animal retina. It was found to be a membrane protein, owing its photosensitivity to the presence of a covalently bound chromophoric group. This group, derived from vitamin A, was appropriately dubbed retinal. In the 1970s a microbial counterpart of this species was discovered in an archaeon, being a membrane protein also harbouring retinal as a chromophore, and named bacteriorhodopsin. Since their discovery a photogenic panorama unfolded, where up to date new members and subspecies with a variety of light-driven functionality have been added to this family. The animal branch, meanwhile categorized as type-2 rhodopsins, turned out to form a large subclass in the superfamily of G protein-coupled receptors and are essential to multiple elements of light-dependent animal sensory physiology. The microbial branch, the type-1 rhodopsins, largely function as light-driven ion pumps or channels, but also contain sensory-active and enzyme-sustaining subspecies. In this review we will follow the development of this exciting membrane protein panorama in a representative number of highlights and will present a prospect of their extraordinary future potential.
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Affiliation(s)
- Willem J. de Grip
- Leiden Institute of Chemistry, Department of Biophysical Organic Chemistry, Leiden University, Leiden, Netherlands
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Srividya Ganapathy
- Department of Imaging Physics, Delft University of Technology, Netherlands
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5
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Sakai K, Shichida Y, Imamoto Y, Yamashita T. Creation of photocyclic vertebrate rhodopsin by single amino acid substitution. eLife 2022; 11:75979. [PMID: 35199641 PMCID: PMC8871353 DOI: 10.7554/elife.75979] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/14/2022] [Indexed: 01/27/2023] Open
Abstract
Opsins are universal photoreceptive proteins in animals and can be classified into three types based on their photoreaction properties. Upon light irradiation, vertebrate rhodopsin forms a metastable active state, which cannot revert back to the original dark state via either photoreaction or thermal reaction. By contrast, after photoreception, most opsins form a stable active state which can photoconvert back to the dark state. Moreover, we recently found a novel type of opsins whose activity is regulated by photocycling. However, the molecular mechanism underlying this diversification of opsins remains unknown. In this study, we showed that vertebrate rhodopsin acquired the photocyclic and photoreversible properties upon introduction of a single mutation at position 188. This revealed that the residue at position 188 contributes to the diversification of photoreaction properties of opsins by its regulation of the recovery from the active state to the original dark state.
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Affiliation(s)
- Kazumi Sakai
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Yoshinori Shichida
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan.,Research Organization for Science and technology, Ritsumeikan University, Kusatsu, Japan
| | - Yasushi Imamoto
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Takahiro Yamashita
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
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6
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Chandler B, Todd L, Smith SO. Magic angle spinning NMR of G protein-coupled receptors. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 128:25-43. [PMID: 35282868 PMCID: PMC10718405 DOI: 10.1016/j.pnmrs.2021.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/26/2021] [Accepted: 10/27/2021] [Indexed: 06/14/2023]
Abstract
G protein-coupled receptors (GPCRs) have a simple seven transmembrane helix architecture which has evolved to recognize a diverse number of chemical signals. The more than 800 GPCRs encoded in the human genome function as receptors for vision, smell and taste, and mediate key physiological processes. Consequently, these receptors are a major target for pharmaceuticals. Protein crystallography and electron cryo-microscopy have provided high resolution structures of many GPCRs in both active and inactive conformations. However, these structures have not sparked a surge in rational drug design, in part because GPCRs are inherently dynamic and the structural changes induced by ligand or drug binding to stabilize inactive or active conformations are often subtle rearrangements in packing or hydrogen-bonding interactions. NMR spectroscopy provides a sensitive probe of local structure and dynamics at specific sites within these receptors as well as global changes in receptor structure and dynamics. These methods can also capture intermediate states and conformations with low populations that provide insights into the activation pathways. We review the use of solid-state magic angle spinning NMR to address the structure and activation mechanisms of GPCRs. The focus is on the large and diverse class A family of receptors. We highlight three specific class A GPCRs in order to illustrate how solid-state, as well as solution-state, NMR spectroscopy can answer questions in the field involving how different GPCR classes and subfamilies are activated by their associated ligands, and how small molecule drugs can modulate GPCR activation.
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Affiliation(s)
- Bianca Chandler
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, United States.
| | - Lauren Todd
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, United States.
| | - Steven O Smith
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, United States.
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New insights into the molecular mechanism of rhodopsin retinitis pigmentosa from the biochemical and functional characterization of G90V, Y102H and I307N mutations. Cell Mol Life Sci 2022; 79:58. [PMID: 34997336 PMCID: PMC8741697 DOI: 10.1007/s00018-021-04086-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 11/29/2021] [Accepted: 12/09/2021] [Indexed: 11/17/2022]
Abstract
Mutations in the photoreceptor protein rhodopsin are known as one of the leading causes of retinal degeneration in humans. Two rhodopsin mutations, Y102H and I307N, obtained in chemically mutagenized mice, are currently the subject of increased interest as relevant models for studying the process of retinal degeneration in humans. Here, we report on the biochemical and functional characterization of the structural and functional alterations of these two rhodopsin mutants and we compare them with the G90V mutant previously analyzed, as a basis for a better understanding of in vivo studies. This mechanistic knowledge is fundamental to use it for developing novel therapeutic approaches for the treatment of inherited retinal degeneration in retinitis pigmentosa. We find that Y102H and I307N mutations affect the inactive–active equilibrium of the receptor. In this regard, the mutations reduce the stability of the inactive conformation but increase the stability of the active conformation. Furthermore, the initial rate of the functional activation of transducin, by the I307N mutant is reduced, but its kinetic profile shows an unusual increase with time suggesting a profound effect on the signal transduction process. This latter effect can be associated with a change in the flexibility of helix 7 and an indirect effect of the mutation on helix 8 and the C-terminal tail of rhodopsin, whose potential role in the functional activation of the receptor has been usually underestimated. In the case of the Y102H mutant, the observed changes can be associated with conformational alterations affecting the folding of the rhodopsin intradiscal domain, and its presumed involvement in the retinal binding process by the receptor.
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8
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Campbell AC, Tanner JJ, Krause KL. Optimisation of Neuraminidase Expression for Use in Drug Discovery by Using HEK293-6E Cells. Viruses 2021; 13:v13101893. [PMID: 34696326 PMCID: PMC8538103 DOI: 10.3390/v13101893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/11/2021] [Accepted: 09/14/2021] [Indexed: 12/02/2022] Open
Abstract
Influenza virus is a highly contagious virus that causes significant human mortality and morbidity annually. The most effective drugs for treating influenza are the neuraminidase inhibitors, but resistance to these inhibitors has emerged, and additional drug discovery research on neuraminidase and other targets is needed. Traditional methods of neuraminidase production from embryonated eggs are cumbersome, while insect cell derived protein is less reflective of neuraminidase produced during human infection. Herein we describe a method for producing neuraminidase from a human cell line, HEK293-6E, and demonstrate the method by producing the neuraminidase from the 1918 H1N1 pandemic influenza strain. This method produced high levels of soluble neuraminidase expression (>3000 EU/mL), was enhanced by including a secretion signal from a viral chemokine binding protein, and does not require co-expression of additional proteins. The neuraminidase produced was of sufficient quantity and purity to support high resolution crystal structure determination. The structure solved using this protein conformed to the previously reported structure. Notably the glycosylation at three asparagine residues was superior in quality to that from insect cell derived neuraminidase. This method of production of neuraminidase should prove useful in further studies, such as the characterisation of inhibitor binding.
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Affiliation(s)
- Ashley C. Campbell
- Department of Biochemistry, University of Otago, 710 Cumberland St., Dunedin 9016, New Zealand;
| | - John J. Tanner
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA;
- Department of Chemistry, University of Missouri, Columbia, MO 65211, USA
| | - Kurt L. Krause
- Department of Biochemistry, University of Otago, 710 Cumberland St., Dunedin 9016, New Zealand;
- Maurice Wilkins Centre for Molecular Biodiscovery, Auckland 1010, New Zealand
- Correspondence:
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9
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Fanelli F, Felline A, Marigo V. Structural aspects of rod opsin and their implication in genetic diseases. Pflugers Arch 2021; 473:1339-1359. [PMID: 33728518 DOI: 10.1007/s00424-021-02546-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 02/17/2021] [Accepted: 02/22/2021] [Indexed: 01/04/2023]
Abstract
Vision in dim-light conditions is triggered by photoactivation of rhodopsin, the visual pigment of rod photoreceptor cells. Rhodopsin is made of a protein, the G protein coupled receptor (GPCR) opsin, and the chromophore 11-cis-retinal. Vertebrate rod opsin is the GPCR best characterized at the atomic level of detail. Since the release of the first crystal structure 20 years ago, a huge number of structures have been released that, in combination with valuable spectroscopic determinations, unveiled most aspects of the photobleaching process. A number of spontaneous mutations of rod opsin have been found linked to vision-impairing diseases like autosomal dominant or autosomal recessive retinitis pigmentosa (adRP or arRP, respectively) and autosomal congenital stationary night blindness (adCSNB). While adCSNB is mainly caused by constitutive activation of rod opsin, RP shows more variegate determinants affecting different aspects of rod opsin function. The vast majority of missense rod opsin mutations affects folding and trafficking and is linked to adRP, an incurable disease that awaits light on its molecular structure determinants. This review article summarizes all major structural information available on vertebrate rod opsin conformational states and the insights gained so far into the structural determinants of adCSNB and adRP linked to rod opsin mutations. Strategies to design small chaperones with therapeutic potential for selected adRP rod opsin mutants will be discussed as well.
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Affiliation(s)
- Francesca Fanelli
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125, Modena, Italy. .,Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, via Campi 287, Modena, 41125, Italy.
| | - Angelo Felline
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125, Modena, Italy
| | - Valeria Marigo
- Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, via Campi 287, Modena, 41125, Italy.,Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125, Modena, Italy
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10
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Kubatova N, Mao J, Eckert CE, Saxena K, Gande SL, Wachtveitl J, Glaubitz C, Schwalbe H. Light Dynamics of the Retinal-Disease-Relevant G90D Bovine Rhodopsin Mutant. Angew Chem Int Ed Engl 2020; 59:15656-15664. [PMID: 32602600 PMCID: PMC7496284 DOI: 10.1002/anie.202003671] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 06/25/2020] [Indexed: 12/11/2022]
Abstract
The RHO gene encodes the G-protein-coupled receptor (GPCR) rhodopsin. Numerous mutations associated with impaired visual cycle have been reported; the G90D mutation leads to a constitutively active mutant form of rhodopsin that causes CSNB disease. We report on the structural investigation of the retinal configuration and conformation in the binding pocket in the dark and light-activated state by solution and MAS-NMR spectroscopy. We found two long-lived dark states for the G90D mutant with the 11-cis retinal bound as Schiff base in both populations. The second minor population in the dark state is attributed to a slight shift in conformation of the covalently bound 11-cis retinal caused by the mutation-induced distortion on the salt bridge formation in the binding pocket. Time-resolved UV/Vis spectroscopy was used to monitor the functional dynamics of the G90D mutant rhodopsin for all relevant time scales of the photocycle. The G90D mutant retains its conformational heterogeneity during the photocycle.
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Affiliation(s)
- Nina Kubatova
- Center for Biomolecular Magnetic ResonanceGoethe University FrankfurtMax-von-Laue-Strasse 760438FrankfurtGermany
- Institute for Organic Chemistry and Chemical BiologyGoethe University FrankfurtMax-von-Laue-Strasse 760438FrankfurtGermany
| | - Jiafei Mao
- Center for Biomolecular Magnetic ResonanceGoethe University FrankfurtMax-von-Laue-Strasse 760438FrankfurtGermany
- Institute of Biophysical ChemistryGoethe University FrankfurtMax-von-Laue-Strasse 960438FrankfurtGermany
| | - Carl Elias Eckert
- Institute of Physical and Theoretical ChemistryGoethe University FrankfurtMax-von-Laue-Strasse 760438FrankfurtGermany
| | - Krishna Saxena
- Center for Biomolecular Magnetic ResonanceGoethe University FrankfurtMax-von-Laue-Strasse 760438FrankfurtGermany
- Institute for Organic Chemistry and Chemical BiologyGoethe University FrankfurtMax-von-Laue-Strasse 760438FrankfurtGermany
| | - Santosh L. Gande
- Center for Biomolecular Magnetic ResonanceGoethe University FrankfurtMax-von-Laue-Strasse 760438FrankfurtGermany
- Institute for Organic Chemistry and Chemical BiologyGoethe University FrankfurtMax-von-Laue-Strasse 760438FrankfurtGermany
| | - Josef Wachtveitl
- Institute of Physical and Theoretical ChemistryGoethe University FrankfurtMax-von-Laue-Strasse 760438FrankfurtGermany
| | - Clemens Glaubitz
- Center for Biomolecular Magnetic ResonanceGoethe University FrankfurtMax-von-Laue-Strasse 760438FrankfurtGermany
- Institute of Biophysical ChemistryGoethe University FrankfurtMax-von-Laue-Strasse 960438FrankfurtGermany
| | - Harald Schwalbe
- Center for Biomolecular Magnetic ResonanceGoethe University FrankfurtMax-von-Laue-Strasse 760438FrankfurtGermany
- Institute for Organic Chemistry and Chemical BiologyGoethe University FrankfurtMax-von-Laue-Strasse 760438FrankfurtGermany
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11
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Kubatova N, Mao J, Eckert CE, Saxena K, Gande SL, Wachtveitl J, Glaubitz C, Schwalbe H. Light Dynamics of the Retinal‐Disease‐Relevant G90D Bovine Rhodopsin Mutant. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202003671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Nina Kubatova
- Center for Biomolecular Magnetic Resonance Goethe University Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt Germany
- Institute for Organic Chemistry and Chemical Biology Goethe University Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt Germany
| | - Jiafei Mao
- Center for Biomolecular Magnetic Resonance Goethe University Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt Germany
- Institute of Biophysical Chemistry Goethe University Frankfurt Max-von-Laue-Strasse 9 60438 Frankfurt Germany
| | - Carl Elias Eckert
- Institute of Physical and Theoretical Chemistry Goethe University Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt Germany
| | - Krishna Saxena
- Center for Biomolecular Magnetic Resonance Goethe University Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt Germany
- Institute for Organic Chemistry and Chemical Biology Goethe University Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt Germany
| | - Santosh L. Gande
- Center for Biomolecular Magnetic Resonance Goethe University Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt Germany
- Institute for Organic Chemistry and Chemical Biology Goethe University Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt Germany
| | - Josef Wachtveitl
- Institute of Physical and Theoretical Chemistry Goethe University Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt Germany
| | - Clemens Glaubitz
- Center for Biomolecular Magnetic Resonance Goethe University Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt Germany
- Institute of Biophysical Chemistry Goethe University Frankfurt Max-von-Laue-Strasse 9 60438 Frankfurt Germany
| | - Harald Schwalbe
- Center for Biomolecular Magnetic Resonance Goethe University Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt Germany
- Institute for Organic Chemistry and Chemical Biology Goethe University Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt Germany
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12
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Errey JC, Fiez-Vandal C. Production of membrane proteins in industry: The example of GPCRs. Protein Expr Purif 2020; 169:105569. [DOI: 10.1016/j.pep.2020.105569] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 01/07/2020] [Accepted: 01/12/2020] [Indexed: 01/08/2023]
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13
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Pamula F, Mühle J, Blanc A, Nehmé R, Edwards PC, Tate CG, Tsai CJ. Strategic Screening and Characterization of the Visual GPCR-mini-G Protein Signaling Complex for Successful Crystallization. J Vis Exp 2020. [PMID: 32225143 PMCID: PMC7250641 DOI: 10.3791/60747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The key to determining crystal structures of membrane protein complexes is the quality of the sample prior to crystallization. In particular, the choice of detergent is critical, because it affects both the stability and monodispersity of the complex. We recently determined the crystal structure of an active state of bovine rhodopsin coupled to an engineered G protein, mini-Go, at 3.1 Å resolution. Here, we detail the procedure for optimizing the preparation of the rhodopsin–mini-Go complex. Dark-state rhodopsin was prepared in classical and neopentyl glycol (NPG) detergents, followed by complex formation with mini-Go under light exposure. The stability of the rhodopsin was assessed by ultraviolet-visible (UV-VIS) spectroscopy, which monitors the reconstitution into rhodopsin of the light-sensitive ligand, 9-cis retinal. Automated size-exclusion chromatography (SEC) was used to characterize the monodispersity of rhodopsin and the rhodopsin–mini-Go complex. SDS-polyacrylamide electrophoresis (SDS-PAGE) confirmed the formation of the complex by identifying a 1:1 molar ratio between rhodopsin and mini-Go after staining the gel with Coomassie blue. After cross-validating all this analytical data, we eliminated unsuitable detergents and continued with the best candidate detergent for large-scale preparation and crystallization. An additional problem arose from the heterogeneity of N-glycosylation. Heterologously-expressed rhodopsin was observed on SDS-PAGE to have two different N-glycosylated populations, which would probably have hindered crystallogenesis. Therefore, different deglycosylation enzymes were tested, and endoglycosidase F1 (EndoF1) produced rhodopsin with a single species of N-glycosylation. With this strategic pipeline for characterizing protein quality, preparation of the rhodopsin–mini-Go complex was optimized to deliver the crystal structure. This was only the third crystal structure of a GPCR–G protein signaling complex. This approach can also be generalized for other membrane proteins and their complexes to facilitate sample preparation and structure determination.
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Affiliation(s)
- Filip Pamula
- Laboratory of Biomolecular Research, Paul Scherrer Institute; Department of Biology, ETH Zürich;
| | - Jonas Mühle
- Laboratory of Biomolecular Research, Paul Scherrer Institute
| | - Alain Blanc
- Center for Radiopharmaceutical Sciences, Paul Scherrer Institute
| | - Rony Nehmé
- Laboratory of Molecular Biology, Medical Research Council
| | | | | | - Ching-Ju Tsai
- Laboratory of Biomolecular Research, Paul Scherrer Institute;
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14
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Barreto CAV, Baptista SJ, Preto AJ, Matos-Filipe P, Mourão J, Melo R, Moreira I. Prediction and targeting of GPCR oligomer interfaces. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 169:105-149. [PMID: 31952684 DOI: 10.1016/bs.pmbts.2019.11.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
GPCR oligomerization has emerged as a hot topic in the GPCR field in the last years. Receptors that are part of these oligomers can influence each other's function, although it is not yet entirely understood how these interactions work. The existence of such a highly complex network of interactions between GPCRs generates the possibility of alternative targets for new therapeutic approaches. However, challenges still exist in the characterization of these complexes, especially at the interface level. Different experimental approaches, such as FRET or BRET, are usually combined to study GPCR oligomer interactions. Computational methods have been applied as a useful tool for retrieving information from GPCR sequences and the few X-ray-resolved oligomeric structures that are accessible, as well as for predicting new and trustworthy GPCR oligomeric interfaces. Machine-learning (ML) approaches have recently helped with some hindrances of other methods. By joining and evaluating multiple structure-, sequence- and co-evolution-based features on the same algorithm, it is possible to dilute the issues of particular structures and residues that arise from the experimental methodology into all-encompassing algorithms capable of accurately predict GPCR-GPCR interfaces. All these methods used as a single or a combined approach provide useful information about GPCR oligomerization and its role in GPCR function and dynamics. Altogether, we present experimental, computational and machine-learning methods used to study oligomers interfaces, as well as strategies that have been used to target these dynamic complexes.
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Affiliation(s)
- Carlos A V Barreto
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Salete J Baptista
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, CTN, LRS, Portugal
| | - António José Preto
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Pedro Matos-Filipe
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Joana Mourão
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Rita Melo
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, CTN, LRS, Portugal
| | - Irina Moreira
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Science and Technology Faculty, University of Coimbra, Coimbra, Portugal.
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15
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Hait S, Mallik S, Basu S, Kundu S. Finding the generalized molecular principles of protein thermal stability. Proteins 2019; 88:788-808. [PMID: 31872464 DOI: 10.1002/prot.25866] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 12/05/2019] [Accepted: 12/14/2019] [Indexed: 11/09/2022]
Abstract
Are there any generalized molecular principles of thermal adaptation? Here, integrating the concepts of structural bioinformatics, sequence analysis, and classical knot theory, we develop a robust computational framework that seeks for mechanisms of thermal adaptation by comparing orthologous mesophilic-thermophilic and mesophilic-hyperthermophilic proteins of remarkable structural and topological similarities, and still leads us to context-independent results. A comprehensive analysis of 4741 high-resolution, non-redundant X-ray crystallographic structures collected from 11 hyperthermophilic, 32 thermophilic and 53 mesophilic prokaryotes unravels at least five "nearly universal" signatures of thermal adaptation, irrespective of the enormous sequence, structure, and functional diversity of the proteins compared. A careful investigation further extracts a set of amino acid changes that can potentially enhance protein thermal stability, and remarkably, these mutations are overrepresented in protein crystallization experiments, in disorder-to-order transitions and in engineered thermostable variants of existing mesophilic proteins. These results could be helpful to find a precise, global picture of thermal adaptation.
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Affiliation(s)
- Suman Hait
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, Kolkata, India
| | - Saurav Mallik
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Sudipto Basu
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, Kolkata, India.,Center of Excellence in Systems Biology and Biomedical Engineering (TEQIP Phase-III), University of Calcutta, Kolkata, India
| | - Sudip Kundu
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, Kolkata, India.,Center of Excellence in Systems Biology and Biomedical Engineering (TEQIP Phase-III), University of Calcutta, Kolkata, India
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16
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Zhu C, Han Q, Samoshkin A, Convertino M, Linton A, Faison EM, Ji RR, Diatchenko L, Dokholyan NV. Stabilization of μ-opioid receptor facilitates its cellular translocation and signaling. Proteins 2019; 87:878-884. [PMID: 31141214 DOI: 10.1002/prot.25751] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/09/2019] [Accepted: 05/26/2019] [Indexed: 01/01/2023]
Abstract
The G protein-coupled μ-opioid receptor (μ-OR) mediates the majority of analgesia effects for morphine and other pain relievers. Despite extensive studies of its structure and activation mechanisms, the inherently low maturation efficiency of μ-OR represents a major hurdle to understanding its function. Here we computationally designed μ-OR mutants with altered stability to probe the relationship between cell-surface targeting, signal transduction, and agonist efficacy. The stabilizing mutation T315Y enhanced μ-OR trafficking to the plasma membrane and significantly promoted the morphine-mediated inhibition of downstream signaling. In contrast, the destabilizing mutation R165Y led to intracellular retention of μ-OR and reduced the response to morphine stimulation. These findings suggest that μ-OR stability is an important factor in regulating receptor signaling and provide a viable avenue to improve the efficacy of analgesics.
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Affiliation(s)
- Cheng Zhu
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Department of Pharmacology, Penn State University College of Medicine, Hershey, Pennsylvania
| | - Qingjian Han
- Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina.,Department of Neurobiology, Duke University Medical Center, Durham, North Carolina
| | - Alexander Samoshkin
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada.,School of the Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Marino Convertino
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Alexander Linton
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
| | - Edgar M Faison
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Ru-Rong Ji
- Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina.,Department of Neurobiology, Duke University Medical Center, Durham, North Carolina
| | - Luda Diatchenko
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
| | - Nikolay V Dokholyan
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Department of Pharmacology, Penn State University College of Medicine, Hershey, Pennsylvania.,Department of Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania.,Department of Biomedical Engineering, Penn State University, Pennsylvania.,Department of Chemistry, Penn State University, Pennsylvania
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17
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Wink LH, Baker DL, Cole JA, Parrill AL. A benchmark study of loop modeling methods applied to G protein-coupled receptors. J Comput Aided Mol Des 2019; 33:573-595. [PMID: 31123958 PMCID: PMC6628340 DOI: 10.1007/s10822-019-00196-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/12/2019] [Indexed: 11/25/2022]
Abstract
G protein-coupled receptors (GPCR) are important drug discovery targets. Despite progress, many GPCR structures have not yet been solved. For these targets, comparative modeling is used in virtual ligand screening to prioritize experimental efforts. However, the structure of extracellular loop 2 (ECL2) is often poorly predicted. This is significant due to involvement of ECL2 in ligand binding for many Class A GPCR. Here we examine the performance of loop modeling protocols available in the Rosetta (cyclic coordinate descent [CCD], KIC with fragments [KICF] and next generation KIC [NGK]) and Molecular Operating Environment (MOE) software suites (de novo search). ECL2 from GPCR crystal structures served as the structure prediction targets and were divided into four sets depending on loop length. Results suggest that KICF and NGK sampled and scored more loop models with sub-angstrom and near-atomic accuracy than CCD or de novo search for loops of 24 or fewer residues. None of the methods were able to sample loop conformations with near-atomic accuracy for the longest targets ranging from 25 to 32 residues based on 1000 models generated. For these long loop targets, increased conformational sampling is necessary. The strongly conserved disulfide bond between Cys3.25 and Cys45.50 in ECL2 proved an effective filter. Setting an upper limit of 5.1 Å on the S-S distance improved the lowest RMSD model included in the top 10 scored structures in Groups 1-4 on average between 0.33 and 1.27 Å. Disulfide bond formation and geometry optimization of ECL2 provided an additional incremental benefit in structure quality.
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Affiliation(s)
- Lee H Wink
- Department of Chemistry, The University of Memphis, Memphis, TN, 38152, USA
| | - Daniel L Baker
- Department of Chemistry, The University of Memphis, Memphis, TN, 38152, USA
| | - Judith A Cole
- Department of Biological Sciences, The University of Memphis, Memphis, TN, 38152, USA
| | - Abby L Parrill
- Department of Chemistry, The University of Memphis, Memphis, TN, 38152, USA.
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18
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Edward Zhou X, Melcher K, Eric Xu H. Structural biology of G protein-coupled receptor signaling complexes. Protein Sci 2019; 28:487-501. [PMID: 30311978 PMCID: PMC6371222 DOI: 10.1002/pro.3526] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 09/30/2018] [Accepted: 10/01/2018] [Indexed: 12/13/2022]
Abstract
G protein-coupled receptors (GPCRs) constitute the largest family of cell surface receptors that mediate numerous cell signaling pathways, and are targets of more than one-third of clinical drugs. Thanks to the advancement of novel structural biology technologies, high-resolution structures of GPCRs in complex with their signaling transducers, including G-protein and arrestin, have been determined. These 3D complex structures have significantly improved our understanding of the molecular mechanism of GPCR signaling and provided a structural basis for signaling-biased drug discovery targeting GPCRs. Here we summarize structural studies of GPCR signaling complexes with G protein and arrestin using rhodopsin as a model system, and highlight the key features of GPCR conformational states in biased signaling including the sequence motifs of receptor TM6 that determine selective coupling of G proteins, and the phosphorylation codes of GPCRs for arrestin recruitment. We envision the future of GPCR structural biology not only to solve more high-resolution complex structures but also to show stepwise GPCR signaling complex assembly and disassembly and dynamic process of GPCR signal transduction.
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Affiliation(s)
- X. Edward Zhou
- Center for Cancer and Cell Biology, Innovation and Integration ProgramVan Andel Research InstituteGrand RapidsMichigan
| | - Karsten Melcher
- Center for Cancer and Cell Biology, Innovation and Integration ProgramVan Andel Research InstituteGrand RapidsMichigan
| | - H. Eric Xu
- Center for Cancer and Cell Biology, Innovation and Integration ProgramVan Andel Research InstituteGrand RapidsMichigan
- Key Laboratory of Receptor Research, VARI‐SIMM Center, Center for Structure and Function of Drug TargetsShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
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19
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Abstract
Activation of G protein-coupled receptors (GPCRs) initiates conformational shifts that trigger interaction with a specific G-protein subtype from a structurally homologous set. A major unsolved problem is the mechanism by which this selectivity is achieved. Structures of GPCR–G protein complexes so far fail to reveal the origin of selectivity because they all involve one G-protein subtype (Gs). In this work, we report a structural model of the activated GPCR rhodopsin in complex with another G-protein subtype (Gi) derived from intermolecular distance mapping with DEER-EPR and refinement with modeling. Comparison of the model with structures of complexes involving Gs reveals distinct GPCR–G protein-binding modes, the differences of which suggest key features of the structural selectivity filter. More than two decades ago, the activation mechanism for the membrane-bound photoreceptor and prototypical G protein-coupled receptor (GPCR) rhodopsin was uncovered. Upon light-induced changes in ligand–receptor interaction, movement of specific transmembrane helices within the receptor opens a crevice at the cytoplasmic surface, allowing for coupling of heterotrimeric guanine nucleotide-binding proteins (G proteins). The general features of this activation mechanism are conserved across the GPCR superfamily. Nevertheless, GPCRs have selectivity for distinct G-protein family members, but the mechanism of selectivity remains elusive. Structures of GPCRs in complex with the stimulatory G protein, Gs, and an accessory nanobody to stabilize the complex have been reported, providing information on the intermolecular interactions. However, to reveal the structural selectivity filters, it will be necessary to determine GPCR–G protein structures involving other G-protein subtypes. In addition, it is important to obtain structures in the absence of a nanobody that may influence the structure. Here, we present a model for a rhodopsin–G protein complex derived from intermolecular distance constraints between the activated receptor and the inhibitory G protein, Gi, using electron paramagnetic resonance spectroscopy and spin-labeling methodologies. Molecular dynamics simulations demonstrated the overall stability of the modeled complex. In the rhodopsin–Gi complex, Gi engages rhodopsin in a manner distinct from previous GPCR–Gs structures, providing insight into specificity determinants.
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20
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Gurevich VV, Gurevich EV, Uversky VN. Arrestins: structural disorder creates rich functionality. Protein Cell 2018; 9:986-1003. [PMID: 29453740 PMCID: PMC6251804 DOI: 10.1007/s13238-017-0501-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 11/27/2017] [Indexed: 01/14/2023] Open
Abstract
Arrestins are soluble relatively small 44–46 kDa proteins that specifically bind hundreds of active phosphorylated GPCRs and dozens of non-receptor partners. There are binding partners that demonstrate preference for each of the known arrestin conformations: free, receptor-bound, and microtubule-bound. Recent evidence suggests that conformational flexibility in every functional state is the defining characteristic of arrestins. Flexibility, or plasticity, of proteins is often described as structural disorder, in contrast to the fixed conformational order observed in high-resolution crystal structures. However, protein-protein interactions often involve highly flexible elements that can assume many distinct conformations upon binding to different partners. Existing evidence suggests that arrestins are no exception to this rule: their flexibility is necessary for functional versatility. The data on arrestins and many other multi-functional proteins indicate that in many cases, “order” might be artificially imposed by highly non-physiological crystallization conditions and/or crystal packing forces. In contrast, conformational flexibility (and its extreme case, intrinsic disorder) is a more natural state of proteins, representing true biological order that underlies their physiologically relevant functions.
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Affiliation(s)
- Vsevolod V Gurevich
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA.
| | - Eugenia V Gurevich
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA.,Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow Region, Russia, 142290
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21
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Lemos A, Melo R, Preto AJ, Almeida JG, Moreira IS, Cordeiro MNDS. In Silico Studies Targeting G-protein Coupled Receptors for Drug Research Against Parkinson's Disease. Curr Neuropharmacol 2018; 16:786-848. [PMID: 29521236 PMCID: PMC6080095 DOI: 10.2174/1570159x16666180308161642] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 02/16/2018] [Accepted: 02/02/2018] [Indexed: 11/22/2022] Open
Abstract
Parkinson's Disease (PD) is a long-term neurodegenerative brain disorder that mainly affects the motor system. The causes are still unknown, and even though currently there is no cure, several therapeutic options are available to manage its symptoms. The development of novel antiparkinsonian agents and an understanding of their proper and optimal use are, indeed, highly demanding. For the last decades, L-3,4-DihydrOxyPhenylAlanine or levodopa (L-DOPA) has been the gold-standard therapy for the symptomatic treatment of motor dysfunctions associated to PD. However, the development of dyskinesias and motor fluctuations (wearing-off and on-off phenomena) associated with long-term L-DOPA replacement therapy have limited its antiparkinsonian efficacy. The investigation for non-dopaminergic therapies has been largely explored as an attempt to counteract the motor side effects associated with dopamine replacement therapy. Being one of the largest cell membrane protein families, G-Protein-Coupled Receptors (GPCRs) have become a relevant target for drug discovery focused on a wide range of therapeutic areas, including Central Nervous System (CNS) diseases. The modulation of specific GPCRs potentially implicated in PD, excluding dopamine receptors, may provide promising non-dopaminergic therapeutic alternatives for symptomatic treatment of PD. In this review, we focused on the impact of specific GPCR subclasses, including dopamine receptors, adenosine receptors, muscarinic acetylcholine receptors, metabotropic glutamate receptors, and 5-hydroxytryptamine receptors, on the pathophysiology of PD and the importance of structure- and ligand-based in silico approaches for the development of small molecules to target these receptors.
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Affiliation(s)
- Agostinho Lemos
- LAQV/REQUIMTE, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007Porto, Portugal
- GIGA Cyclotron Research Centre In Vivo Imaging, University of Liège, 4000Liège, Belgium
| | - Rita Melo
- CNC - Center for Neuroscience and Cell Biology, Faculty of Medicine, University of Coimbra, Rua Larga, 3004-517Coimbra, Portugal
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (ao km 139,7), 2695-066 Bobadela LRS, Portugal
| | - Antonio Jose Preto
- CNC - Center for Neuroscience and Cell Biology, Faculty of Medicine, University of Coimbra, Rua Larga, 3004-517Coimbra, Portugal
| | - Jose Guilherme Almeida
- CNC - Center for Neuroscience and Cell Biology, Faculty of Medicine, University of Coimbra, Rua Larga, 3004-517Coimbra, Portugal
| | - Irina Sousa Moreira
- CNC - Center for Neuroscience and Cell Biology, Faculty of Medicine, University of Coimbra, Rua Larga, 3004-517Coimbra, Portugal
- Bijvoet Center for Biomolecular Research, Faculty of Science - Chemistry, Utrecht University, Utrecht, 3584CH, The Netherlands
| | - Maria Natalia Dias Soeiro Cordeiro
- LAQV/REQUIMTE, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007Porto, Portugal
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22
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Krebs MP, Collin GB, Hicks WL, Yu M, Charette JR, Shi LY, Wang J, Naggert JK, Peachey NS, Nishina PM. Mouse models of human ocular disease for translational research. PLoS One 2017; 12:e0183837. [PMID: 28859131 PMCID: PMC5578669 DOI: 10.1371/journal.pone.0183837] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 08/12/2017] [Indexed: 01/24/2023] Open
Abstract
Mouse models provide a valuable tool for exploring pathogenic mechanisms underlying inherited human disease. Here, we describe seven mouse models identified through the Translational Vision Research Models (TVRM) program, each carrying a new allele of a gene previously linked to retinal developmental and/or degenerative disease. The mutations include four alleles of three genes linked to human nonsyndromic ocular diseases (Aipl1tvrm119, Aipl1tvrm127, Rpgrip1tvrm111, RhoTvrm334) and three alleles of genes associated with human syndromic diseases that exhibit ocular phentoypes (Alms1tvrm102, Clcn2nmf289, Fkrptvrm53). Phenotypic characterization of each model is provided in the context of existing literature, in some cases refining our current understanding of specific disease attributes. These murine models, on fixed genetic backgrounds, are available for distribution upon request and may be useful for understanding the function of the gene in the retina, the pathological mechanisms induced by its disruption, and for testing experimental approaches to treat the corresponding human ocular diseases.
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Affiliation(s)
- Mark P. Krebs
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Gayle B. Collin
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Wanda L. Hicks
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Minzhong Yu
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio, United States of America
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, United States of America
| | | | - Lan Ying Shi
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Jieping Wang
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | | | - Neal S. Peachey
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio, United States of America
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, United States of America
- Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, United States of America
| | - Patsy M. Nishina
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
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23
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Gacasan SB, Baker DL, Parrill AL. G protein-coupled receptors: the evolution of structural insight. AIMS BIOPHYSICS 2017; 4:491-527. [PMID: 29951585 DOI: 10.3934/biophy.2017.3.491] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
G protein-coupled receptors (GPCR) comprise a diverse superfamily of over 800 proteins that have gained relevance as biological targets for pharmaceutical drug design. Although these receptors have been investigated for decades, three-dimensional structures of GPCR have only recently become available. In this review, we focus on the technological advancements that have facilitated efforts to gain insights into GPCR structure. Progress in these efforts began with the initial crystal structure determination of rhodopsin (PDB: 1F88) in 2000 and has continued to the most recently published structure of the A1AR (PDB: 5UEN) in 2017. Numerous experimental developments over the past two decades have opened the door for widespread GPCR structural characterization. These efforts have resulted in the determination of three-dimensional structures for over 40 individual GPCR family members. Herein we present a comprehensive list and comparative analysis of over 180 individual GPCR structures. This includes a summary of different GPCR functional states crystallized with agonists, dual agonists, partial agonists, inverse agonists, antagonists, and allosteric modulators.
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Affiliation(s)
- Samantha B Gacasan
- Department of Chemistry, University of Memphis, 3744 Walker Ave, Memphis, TN 38152, USA
| | - Daniel L Baker
- Department of Chemistry, University of Memphis, 3744 Walker Ave, Memphis, TN 38152, USA
| | - Abby L Parrill
- Department of Chemistry, University of Memphis, 3744 Walker Ave, Memphis, TN 38152, USA
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24
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Sandoval A, Eichler S, Madathil S, Reeves PJ, Fahmy K, Böckmann RA. The Molecular Switching Mechanism at the Conserved D(E)RY Motif in Class-A GPCRs. Biophys J 2017; 111:79-89. [PMID: 27410736 DOI: 10.1016/j.bpj.2016.06.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 05/31/2016] [Accepted: 06/08/2016] [Indexed: 10/21/2022] Open
Abstract
The disruption of ionic and H-bond interactions between the cytosolic ends of transmembrane helices TM3 and TM6 of class-A (rhodopsin-like) G protein-coupled receptors (GPCRs) is a hallmark for their activation by chemical or physical stimuli. In the bovine photoreceptor rhodopsin, this is accompanied by proton uptake at Glu(134) in the class-conserved D(E)RY motif. Studies on TM3 model peptides proposed a crucial role of the lipid bilayer in linking protonation to stabilization of an active state-like conformation. However, the molecular details of this linkage could not be resolved and have been addressed in this study by molecular dynamics (MD) simulations on TM3 model peptides in a bilayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). We show that protonation of the conserved glutamic acid alters the peptide insertion depth in the membrane, its side-chain rotamer preferences, and stabilizes the C-terminal helical structure. These factors contribute to the rise of the side-chain pKa (> 6) and to reduced polarity around the TM3 C terminus as confirmed by fluorescence spectroscopy. Helix stabilization requires the protonated carboxyl group; unexpectedly, this stabilization could not be evoked with an amide in MD simulations. Additionally, time-resolved Fourier transform infrared (FTIR) spectroscopy of TM3 model peptides revealed a different kinetics for lipid ester carbonyl hydration, suggesting that the carboxyl is linked to more extended H-bond clusters than an amide. Remarkably, this was seen as well in DOPC-reconstituted Glu(134)- and Gln(134)-containing bovine opsin mutants and demonstrates that the D(E)RY motif is a hydrated microdomain. The function of the D(E)RY motif as a proton switch is suggested to be based on the reorganization of the H-bond network at the membrane interface.
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Affiliation(s)
- Angelica Sandoval
- Computational Biology, Department of Biology, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Stefanie Eichler
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, and Technische Universität Dresden, Dresden, Germany
| | - Sineej Madathil
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Philip J Reeves
- School of Biological Sciences, University of Essex, Colchester, United Kingdom
| | - Karim Fahmy
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, and Technische Universität Dresden, Dresden, Germany.
| | - Rainer A Böckmann
- Computational Biology, Department of Biology, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany.
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25
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Devine EL, Theobald DL, Oprian DD. Relocating the Active-Site Lysine in Rhodopsin: 2. Evolutionary Intermediates. Biochemistry 2016; 55:4864-70. [PMID: 27486845 DOI: 10.1021/acs.biochem.6b00478] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The visual pigment rhodopsin is a G protein-coupled receptor that covalently binds its retinal chromophore via a Schiff base linkage to an active-site Lys residue in the seventh transmembrane helix. Although this residue is strictly conserved among all type II retinylidene proteins, we found previously that the active-site Lys in bovine rhodopsin (Lys296) can be moved to three other locations (G90K, T94K, S186K) while retaining the ability to form a pigment with retinal and to activate transducin in a light-dependent manner [ Devine et al. ( 2013 ) Proc. Natl. Acad. Sci. USA 110 , 13351 - 13355 ]. Because the active-site Lys is not functionally constrained to be in helix seven, it is possible that it could relocate within the protein, most likely via an evolutionary intermediate with two active-site Lys. Therefore, in this study we characterized potential evolutionary intermediates with two Lys in the active site. Four mutant rhodopsins were prepared in which the original Lys296 was left untouched and a second Lys residue was substituted for G90K, T94K, S186K, or F293K. All four constructs covalently bind 11-cis-retinal, form a pigment, and activate transducin in a light-dependent manner. These results demonstrate that rhodopsin can tolerate a second Lys in the retinal binding pocket and suggest that an evolutionary intermediate with two Lys could allow migration of the Schiff base Lys to a position other than the observed, highly conserved location in the seventh TM helix. From sequence-based searches, we identified two groups of natural opsins, insect UV cones and neuropsins, that contain Lys residues at two positions in their active sites and also have intriguing spectral similarities to the mutant rhodopsins studied here.
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Affiliation(s)
- Erin L Devine
- Department of Biochemistry, Brandeis University , 415 South Street, Waltham, Massachusetts 02454, United States
| | - Douglas L Theobald
- Department of Biochemistry, Brandeis University , 415 South Street, Waltham, Massachusetts 02454, United States
| | - Daniel D Oprian
- Department of Biochemistry, Brandeis University , 415 South Street, Waltham, Massachusetts 02454, United States
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Singhal A, Guo Y, Matkovic M, Schertler G, Deupi X, Yan EC, Standfuss J. Structural role of the T94I rhodopsin mutation in congenital stationary night blindness. EMBO Rep 2016; 17:1431-1440. [PMID: 27458239 DOI: 10.15252/embr.201642671] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/07/2016] [Indexed: 11/09/2022] Open
Abstract
Congenital stationary night blindness (CSNB) is an inherited and non-progressive retinal dysfunction. Here, we present the crystal structure of CSNB-causing T94I2.61 rhodopsin in the active conformation at 2.3 Å resolution. The introduced hydrophobic side chain prolongs the lifetime of the G protein activating metarhodopsin-II state by establishing a direct van der Waals contact with K2967.43, the site of retinal attachment. This is in stark contrast to the light-activated state of the CSNB-causing G90D2.57 mutation, where the charged mutation forms a salt bridge with K2967.43 To find the common denominator between these two functional modifications, we combined our structural data with a kinetic biochemical analysis and molecular dynamics simulations. Our results indicate that both the charged G90D2.57 and the hydrophobic T94I2.61 mutation alter the dark state by weakening the interaction between the Schiff base (SB) and its counterion E1133.28 We propose that this interference with the tight regulation of the dim light photoreceptor rhodopsin increases background noise in the visual system and causes the loss of night vision characteristic for CSNB patients.
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Affiliation(s)
- Ankita Singhal
- Division of Biology and Chemistry, Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland
| | - Ying Guo
- Department of Chemistry, Yale University, New Haven, CT, USA
| | - Milos Matkovic
- Division of Biology and Chemistry, Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland
| | - Gebhard Schertler
- Division of Biology and Chemistry, Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland Deparment of Biology, ETH Zurich, Zürich, Switzerland
| | - Xavier Deupi
- Division of Biology and Chemistry, Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland Condensed Matter Theory Group, Paul Scherrer Institute, Villigen, Switzerland
| | - Elsa Cy Yan
- Department of Chemistry, Yale University, New Haven, CT, USA
| | - Joerg Standfuss
- Division of Biology and Chemistry, Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland
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27
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Jones Brunette AM, Sinha A, David L, Farrens DL. Evidence that the Rhodopsin Kinase (GRK1) N-Terminus and the Transducin Gα C-Terminus Interact with the Same "Hydrophobic Patch" on Rhodopsin TM5. Biochemistry 2016; 55:3123-35. [PMID: 27078130 DOI: 10.1021/acs.biochem.6b00328] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Phosphorylation of G protein-coupled receptors (GPCRs) terminates their ability to couple with and activate G proteins by increasing their affinity for arrestins. Unfortunately, detailed information regarding how GPCRs interact with the kinases responsible for their phosphorylation is still limited. Here, we purified fully functional GPCR kinase 1 (GRK1) using a rapid method and used it to gain insights into how this important kinase interacts with the GPCR rhodopsin. Specifically, we find that GRK1 uses the same site on rhodopsin as the transducin (Gt) Gtα C-terminal tail and the arrestin "finger loop", a cleft formed in the cytoplasmic face of the receptor upon activation. Our studies also show GRK1 requires two conserved residues located in this cleft (L226 and V230) that have been shown to be required for Gt activation due to their direct interactions with hydrophobic residues on the Gα C-terminal tail. Our data and modeling studies are consistent with the idea that all three proteins (Gt, GRK1, and visual arrestin) bind, at least in part, in the same site on rhodopsin and interact with the receptor through a similar hydrophobic contact-driven mechanism.
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Affiliation(s)
- Amber M Jones Brunette
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University , Portland, Oregon 97239-3098, United States
| | - Abhinav Sinha
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University , Portland, Oregon 97239-3098, United States
| | - Larry David
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University , Portland, Oregon 97239-3098, United States
| | - David L Farrens
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University , Portland, Oregon 97239-3098, United States
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28
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Liu D, Wüthrich K. Ring current shifts in (19)F-NMR of membrane proteins. JOURNAL OF BIOMOLECULAR NMR 2016; 65:1-5. [PMID: 27240587 DOI: 10.1007/s10858-016-0022-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 02/06/2016] [Indexed: 06/05/2023]
Abstract
Fluorine-19 NMR markers are attractive reporter groups for use in studies of complex biomacromolecular systems, in particular also for studies of function-related conformational equilibria and rate processes in membrane proteins. Advantages of (19)F-NMR probes include high sensitivity of the (19)F chemical shifts to variations in the non-covalent environment. Nonetheless, in studies of G protein-coupled receptors (GPCR) we encountered situations where (19)F chemical shifts were not responsive to conformational changes that had been implicated by other methods. This prompted us to examine possible effects of aromatic ring current fields on the chemical shifts of (19)F-NMR probes used in GPCRs. Analysis of previously reported (19)F-NMR data on the β2-adrenergic receptor and mammalian rhodopsin showed that all (19)F-labeling sites which manifested conformational changes are located near aromatic residues. Although ring current effects are small when compared to other known non-covalent effects on (19)F chemical shifts, there is thus an indication that their contributions are significant when studying activation processes in GPCRs, since the observed activation-related (19)F-NMR chemical shifts are comparable in size to the calculated ring current shifts. Considering the impact of ring current shifts may thus be helpful in identifying promising indigenous or engineered labeling sites for future (19)F-NMR studies of GPCR activation, and novel information may be obtained on the nature of conformational rearrangements near the (19)F-labels. It will then also be interesting to see if the presently indicated role of ring current shifts in membrane protein studies with (19)F-NMR markers can be substantiated by a more extensive data base resulting from future studies.
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Affiliation(s)
- Dongsheng Liu
- iHuman Institute, ShanghaiTech University, 99 HaiKe Road, Shanghai, 201210, China
| | - Kurt Wüthrich
- iHuman Institute, ShanghaiTech University, 99 HaiKe Road, Shanghai, 201210, China.
- Department of Integrative Structural and Computational Biology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA.
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29
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Fernández-Sampedro MA, Invergo BM, Ramon E, Bertranpetit J, Garriga P. Functional role of positively selected amino acid substitutions in mammalian rhodopsin evolution. Sci Rep 2016; 6:21570. [PMID: 26865329 PMCID: PMC4749998 DOI: 10.1038/srep21570] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 01/27/2016] [Indexed: 12/22/2022] Open
Abstract
Visual rhodopsins are membrane proteins that function as light photoreceptors in the vertebrate retina. Specific amino acids have been positively selected in visual pigments during mammal evolution, which, as products of adaptive selection, would be at the base of important functional innovations. We have analyzed the top candidates for positive selection at the specific amino acids and the corresponding reverse changes (F13M, Q225R and A346S) in order to unravel the structural and functional consequences of these important sites in rhodopsin evolution. We have constructed, expressed and immunopurified the corresponding mutated pigments and analyzed their molecular phenotypes. We find that position 13 is very important for the folding of the receptor and also for proper protein glycosylation. Position 225 appears to be important for the function of the protein affecting the G-protein activation process, and position 346 would also regulate functionality of the receptor by enhancing G-protein activation and presumably affecting protein phosphorylation by rhodopsin kinase. Our results represent a link between the evolutionary analysis, which pinpoints the specific amino acid positions in the adaptive process, and the structural and functional analysis, closer to the phenotype, making biochemical sense of specific selected genetic sequences in rhodopsin evolution.
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Affiliation(s)
- Miguel A Fernández-Sampedro
- Grup de Biotecnologia Molecular i Industrial, Centre de Biotecnologia Molecular, Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, Edifici Gaia, Rambla de Sant Nebridi 22, 08222 Terrassa, Catalonia, Spain
| | - Brandon M Invergo
- IBE - Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), CEXS-UPF-PRBB, Barcelona, Catalonia, Spain
| | - Eva Ramon
- Grup de Biotecnologia Molecular i Industrial, Centre de Biotecnologia Molecular, Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, Edifici Gaia, Rambla de Sant Nebridi 22, 08222 Terrassa, Catalonia, Spain
| | - Jaume Bertranpetit
- IBE - Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), CEXS-UPF-PRBB, Barcelona, Catalonia, Spain
| | - Pere Garriga
- Grup de Biotecnologia Molecular i Industrial, Centre de Biotecnologia Molecular, Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, Edifici Gaia, Rambla de Sant Nebridi 22, 08222 Terrassa, Catalonia, Spain
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Andréll J, Edwards PC, Zhang F, Daly M, Tate CG. Generation of Tetracycline-Inducible Mammalian Cell Lines by Flow Cytometry for Improved Overproduction of Membrane Proteins. Methods Mol Biol 2016; 1432:63-78. [PMID: 27485330 DOI: 10.1007/978-1-4939-3637-3_5] [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] [Indexed: 12/12/2022]
Abstract
Overexpression of mammalian membrane proteins in mammalian cells is an effective strategy to produce sufficient protein for biophysical analyses and structural studies, because the cells generally express proteins in a correctly folded state. However, obtaining high levels of expression suitable for protein purification on a milligram scale can be challenging. As membrane protein overexpression often has a negative impact on cell viability, it is usual to make stable cell lines where the protein of interest is expressed from an inducible promoter. Here we describe a methodology for optimizing the inducible production of any membrane protein fused to GFP through the isolation of clonal cell lines. Flow cytometry is used to sort uninduced cells and the most fluorescent 5 % of the cell population are used to make clonal cell lines.
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Affiliation(s)
- Juni Andréll
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Patricia C Edwards
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Fan Zhang
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Maria Daly
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Christopher G Tate
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
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31
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Mattle D, Singhal A, Schmid G, Dawson R, Standfuss J. Mammalian expression, purification, and crystallization of rhodopsin variants. Methods Mol Biol 2015; 1271:39-54. [PMID: 25697515 DOI: 10.1007/978-1-4939-2330-4_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
After 25 years of intensive research, the understanding of how photoreceptors in the eye perceive light and convert it into nerve signals has largely advanced. Central to this is the structural and mechanistic exploration of the G protein-coupled receptor rhodopsin acting as a dim-light sensing pigment in the retina. Investigation of rhodopsin by X-ray crystallographic, electron microscopic, and biochemical means depends on the ability to produce and isolate pure rhodopsin protein. Robust and well-defined protocols permit the production and crystallization of rhodopsin variants to investigate the inactive ground, the fully activated metarhodopsin II state, or disease-causing rhodopsin mutations. This chapter details how we express and purify biologically active variants of rhodopsin from HEK293S GnTI(-) cells in a quality and quantity suitable for biochemical assays, crystallization, and structure determination.
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Affiliation(s)
- Daniel Mattle
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, CH-5232, Switzerland
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32
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How Can Mutations Thermostabilize G-Protein-Coupled Receptors? Trends Pharmacol Sci 2015; 37:37-46. [PMID: 26547284 DOI: 10.1016/j.tips.2015.09.005] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 09/14/2015] [Accepted: 09/21/2015] [Indexed: 01/04/2023]
Abstract
Structures of over 30 different G-protein-coupled receptors (GPCRs) have advanced our understanding of cell signaling and have provided a foundation for structure-guided drug design. This exciting progress has required the development of three complementary methods to facilitate GPCR crystallization, one of which is the thermostabilization of receptors by systematic mutagenesis. However, the reason why a particular mutation, or combination of mutations, stabilizes the receptor is not always evident from a static crystal structure. Molecular dynamics (MD) simulations have been used to identify and estimate the energetic factors that affect thermostability through comparing the dynamics of the thermostabilized receptors with structure-based models of the wild-type receptor. The data indicate that receptors are stabilized through a combination of factors, including an increase in receptor rigidity, a decrease in collective motion, reduced stress at specific residues, and the presence of ordered water molecules. Predicting thermostabilizing mutations computationally represents a major challenge for the field.
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33
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The leukotriene B 4 receptor BLT1 is stabilized by transmembrane helix capping mutations. Biochem Biophys Rep 2015; 4:243-249. [PMID: 29124210 PMCID: PMC5668910 DOI: 10.1016/j.bbrep.2015.09.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 09/12/2015] [Accepted: 09/14/2015] [Indexed: 11/29/2022] Open
Abstract
In this study, we introduced structure-based rational mutations in the guinea pig leukotriene B4 receptor (gpBLT1) in order to enhance the stabilization of the protein. Elements thought to be unfavorable for the stability of gpBLT1 were extracted based on the stabilization elements established in soluble proteins, determined crystal structures of G-protein-coupled receptors (GPCRs), and multiple sequence alignment. The two unfavorable residues His832.67 and Lys883.21, located at helix capping sites, were replaced with Gly (His83Gly2.67 and Lys88Gly3.21). The modified protein containing His83Gly2.67/Lys88Gly3.21 was highly expressed, solubilized, and purified and exhibited improved thermal stability by 4 °C in comparison with that of the original gpBLT1 construct. Owing to the double mutation, the expression level increased by 6-fold (Bmax=311 pmol/mg) in the membrane fraction of Pichia pastoris. The ligand binding affinity was similar to that of the original gpBLT1 without the mutations. Similar unfavorable residues have been observed at helix capping sites in many other GPCRs; therefore, the replacement of such residues with more favorable residues will improve stabilization of the GPCR structure for the crystallization. Point mutations were rationally designed to stabilize LTB4 receptor (BLT1). The stability of mutant His83Gly2.67/Lys88Gly3.21 improved by 5 °C. BLT1 expression by P. pastoris was increased 6-fold. Mutations were designed to replace unfavorable residues at the helix capping site. This method would be useful for the stabilization of the other membrane proteins.
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34
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Membrane protein structural biology using X-ray free electron lasers. Curr Opin Struct Biol 2015; 33:115-25. [DOI: 10.1016/j.sbi.2015.08.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 08/13/2015] [Accepted: 08/13/2015] [Indexed: 11/20/2022]
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35
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Abstract
G-protein-coupled receptors (GPCRs) signal primarily through G proteins or arrestins. Arrestin binding to GPCRs blocks G protein interaction and redirects signalling to numerous G-protein-independent pathways. Here we report the crystal structure of a constitutively active form of human rhodopsin bound to a pre-activated form of the mouse visual arrestin, determined by serial femtosecond X-ray laser crystallography. Together with extensive biochemical and mutagenesis data, the structure reveals an overall architecture of the rhodopsin-arrestin assembly in which rhodopsin uses distinct structural elements, including transmembrane helix 7 and helix 8, to recruit arrestin. Correspondingly, arrestin adopts the pre-activated conformation, with a ∼20° rotation between the amino and carboxy domains, which opens up a cleft in arrestin to accommodate a short helix formed by the second intracellular loop of rhodopsin. This structure provides a basis for understanding GPCR-mediated arrestin-biased signalling and demonstrates the power of X-ray lasers for advancing the frontiers of structural biology.
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36
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Piscitelli CL, Kean J, de Graaf C, Deupi X. A Molecular Pharmacologist's Guide to G Protein-Coupled Receptor Crystallography. Mol Pharmacol 2015; 88:536-51. [PMID: 26152196 DOI: 10.1124/mol.115.099663] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/07/2015] [Indexed: 12/14/2022] Open
Abstract
G protein-coupled receptor (GPCR) structural biology has progressed dramatically in the last decade. There are now over 120 GPCR crystal structures deposited in the Protein Data Bank of 32 different receptors from families scattered across the phylogenetic tree, including class B, C, and Frizzled GPCRs. These structures have been obtained in combination with a wide variety of ligands and captured in a range of conformational states. This surge in structural knowledge has enlightened research into the molecular recognition of biologically active molecules, the mechanisms of receptor activation, the dynamics of functional selectivity, and fueled structure-based drug design efforts for GPCRs. Here we summarize the innovations in both protein engineering/molecular biology and crystallography techniques that have led to these advances in GPCR structural biology and discuss how they may influence the resulting structural models. We also provide a brief molecular pharmacologist's guide to GPCR X-ray crystallography, outlining some key aspects in the process of structure determination, with the goal to encourage noncrystallographers to interrogate structures at the molecular level. Finally, we show how chemogenomics approaches can be used to marry the wealth of existing receptor pharmacology data with the expanding repertoire of structures, providing a deeper understanding of the mechanistic details of GPCR function.
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Affiliation(s)
- Chayne L Piscitelli
- Laboratory of Biomolecular Research, Department of Biology and Chemistry (C.L.P., X.D.), and Condensed Matter Theory Group, Department of Research with Neutrons and Muons (X.D.), Paul Scherrer Institute, Villigen, Switzerland; Heptares Therapeutics Ltd., Welwyn Garden City, United Kingdom (J.K.); and Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems, VU University of Amsterdam, Amsterdam, The Netherlands (C.G.)
| | - James Kean
- Laboratory of Biomolecular Research, Department of Biology and Chemistry (C.L.P., X.D.), and Condensed Matter Theory Group, Department of Research with Neutrons and Muons (X.D.), Paul Scherrer Institute, Villigen, Switzerland; Heptares Therapeutics Ltd., Welwyn Garden City, United Kingdom (J.K.); and Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems, VU University of Amsterdam, Amsterdam, The Netherlands (C.G.)
| | - Chris de Graaf
- Laboratory of Biomolecular Research, Department of Biology and Chemistry (C.L.P., X.D.), and Condensed Matter Theory Group, Department of Research with Neutrons and Muons (X.D.), Paul Scherrer Institute, Villigen, Switzerland; Heptares Therapeutics Ltd., Welwyn Garden City, United Kingdom (J.K.); and Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems, VU University of Amsterdam, Amsterdam, The Netherlands (C.G.)
| | - Xavier Deupi
- Laboratory of Biomolecular Research, Department of Biology and Chemistry (C.L.P., X.D.), and Condensed Matter Theory Group, Department of Research with Neutrons and Muons (X.D.), Paul Scherrer Institute, Villigen, Switzerland; Heptares Therapeutics Ltd., Welwyn Garden City, United Kingdom (J.K.); and Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems, VU University of Amsterdam, Amsterdam, The Netherlands (C.G.)
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37
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Panneels V, Wu W, Tsai CJ, Nogly P, Rheinberger J, Jaeger K, Cicchetti G, Gati C, Kick LM, Sala L, Capitani G, Milne C, Padeste C, Pedrini B, Li XD, Standfuss J, Abela R, Schertler G. Time-resolved structural studies with serial crystallography: A new light on retinal proteins. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2015; 2:041718. [PMID: 26798817 PMCID: PMC4711639 DOI: 10.1063/1.4922774] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 06/03/2015] [Indexed: 05/19/2023]
Abstract
Structural information of the different conformational states of the two prototypical light-sensitive membrane proteins, bacteriorhodopsin and rhodopsin, has been obtained in the past by X-ray cryo-crystallography and cryo-electron microscopy. However, these methods do not allow for the structure determination of most intermediate conformations. Recently, the potential of X-Ray Free Electron Lasers (X-FELs) for tracking the dynamics of light-triggered processes by pump-probe serial femtosecond crystallography has been demonstrated using 3D-micron-sized crystals. In addition, X-FELs provide new opportunities for protein 2D-crystal diffraction, which would allow to observe the course of conformational changes of membrane proteins in a close-to-physiological lipid bilayer environment. Here, we describe the strategies towards structural dynamic studies of retinal proteins at room temperature, using injector or fixed-target based serial femtosecond crystallography at X-FELs. Thanks to recent progress especially in sample delivery methods, serial crystallography is now also feasible at synchrotron X-ray sources, thus expanding the possibilities for time-resolved structure determination.
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Affiliation(s)
- Valérie Panneels
- Laboratory of Biomolecular Research, Paul Scherrer Institute , 5232 Villigen PSI, Switzerland
| | - Wenting Wu
- Laboratory of Biomolecular Research, Paul Scherrer Institute , 5232 Villigen PSI, Switzerland
| | - Ching-Ju Tsai
- Laboratory of Biomolecular Research, Paul Scherrer Institute , 5232 Villigen PSI, Switzerland
| | - Przemek Nogly
- Laboratory of Biomolecular Research, Paul Scherrer Institute , 5232 Villigen PSI, Switzerland
| | - Jan Rheinberger
- Laboratory of Biomolecular Research, Paul Scherrer Institute , 5232 Villigen PSI, Switzerland
| | - Kathrin Jaeger
- Laboratory of Biomolecular Research, Paul Scherrer Institute , 5232 Villigen PSI, Switzerland
| | - Gregor Cicchetti
- Laboratory of Biomolecular Research, Paul Scherrer Institute , 5232 Villigen PSI, Switzerland
| | | | - Leonhard M Kick
- Laboratory of Biomolecular Research, Paul Scherrer Institute , 5232 Villigen PSI, Switzerland
| | - Leonardo Sala
- Scientific Computing, Paul Scherrer Institute , 5232 Villigen PSI, Switzerland
| | - Guido Capitani
- Laboratory of Biomolecular Research, Paul Scherrer Institute , 5232 Villigen PSI, Switzerland
| | - Chris Milne
- SwissFEL Paul Scherrer Institute , 5232 Villigen PSI, Switzerland
| | - Celestino Padeste
- Lab for Micro- and Nanotechnology, Paul Scherrer Institute , 5232 Villigen PSI, Switzerland
| | - Bill Pedrini
- SwissFEL Paul Scherrer Institute , 5232 Villigen PSI, Switzerland
| | - Xiao-Dan Li
- Laboratory of Biomolecular Research, Paul Scherrer Institute , 5232 Villigen PSI, Switzerland
| | - Jörg Standfuss
- Laboratory of Biomolecular Research, Paul Scherrer Institute , 5232 Villigen PSI, Switzerland
| | - Rafael Abela
- SwissFEL Paul Scherrer Institute , 5232 Villigen PSI, Switzerland
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38
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Heydenreich FM, Vuckovic Z, Matkovic M, Veprintsev DB. Stabilization of G protein-coupled receptors by point mutations. Front Pharmacol 2015; 6:82. [PMID: 25941489 PMCID: PMC4403299 DOI: 10.3389/fphar.2015.00082] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 03/31/2015] [Indexed: 11/13/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are flexible integral membrane proteins involved in transmembrane signaling. Their involvement in many physiological processes makes them interesting targets for drug development. Determination of the structure of these receptors will help to design more specific drugs, however, their structural characterization has so far been hampered by the low expression and their inherent instability in detergents which made protein engineering indispensable for structural and biophysical characterization. Several approaches to stabilize the receptors in a particular conformation have led to breakthroughs in GPCR structure determination. These include truncations of the flexible regions, stabilization by antibodies and nanobodies, fusion partners, high affinity and covalently bound ligands as well as conformational stabilization by mutagenesis. In this review we focus on stabilization of GPCRs by insertion of point mutations, which lead to increased conformational and thermal stability as well as improved expression levels. We summarize existing mutagenesis strategies with different coverage of GPCR sequence space and depth of information, design and transferability of mutations and the molecular basis for stabilization. We also discuss whether mutations alter the structure and pharmacological properties of GPCRs.
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Affiliation(s)
- Franziska M Heydenreich
- Laboratory of Biomolecular Research, Paul Scherrer Institut Villigen, Switzerland ; Department of Biology, ETH Zürich Zürich, Switzerland
| | - Ziva Vuckovic
- Laboratory of Biomolecular Research, Paul Scherrer Institut Villigen, Switzerland ; Department of Biology, ETH Zürich Zürich, Switzerland
| | - Milos Matkovic
- Laboratory of Biomolecular Research, Paul Scherrer Institut Villigen, Switzerland ; Department of Biology, ETH Zürich Zürich, Switzerland
| | - Dmitry B Veprintsev
- Laboratory of Biomolecular Research, Paul Scherrer Institut Villigen, Switzerland ; Department of Biology, ETH Zürich Zürich, Switzerland
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39
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Lin CY, Huang Z, Wen W, Wu A, Wang C, Niu L. Enhancing Protein Expression in HEK-293 Cells by Lowering Culture Temperature. PLoS One 2015; 10:e0123562. [PMID: 25893827 PMCID: PMC4404257 DOI: 10.1371/journal.pone.0123562] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 03/05/2015] [Indexed: 11/30/2022] Open
Abstract
Animal cells and cell lines, such as HEK-293 cells, are commonly cultured at 37°C. These cells are often used to express recombinant proteins. Having a higher expression level or a higher protein yield is generally desirable. As we demonstrate in this study, dropping culture temperature to 33°C, but not lower, 24 hours after transient transfection in HEK-293S cells will give rise to ~1.5-fold higher expression of green fluorescent protein (GFP) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. By following the time course of the GFP-expressing cells growing at 37°C and 33°C from 24 hours after transfection (including 19 hours recovery at 37°C in the normal growth medium), we found that a mild hypothermia (i.e., 33°C) reduces the growth rate of HEK-293S cells, while increasing cellular productivity of recombinant proteins. As a result, green cells remain undivided in a longer period of time. Not surprisingly, the property of a recombinant protein expressed in the cells grown at 33°C is unaffected, as shown by the use of AMPA receptors. We further demonstrate with the use of PC12 cells that this method may be especially useful when a recombinant protein is difficult to express using a chemical-based, transient transfection method.
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Affiliation(s)
- Chi-Yen Lin
- Department of Chemistry, and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York, 12222, United States of America
| | - Zhen Huang
- Department of Chemistry, and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York, 12222, United States of America
| | - Wei Wen
- Department of Chemistry, and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York, 12222, United States of America
| | - Andrew Wu
- Department of Chemistry, and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York, 12222, United States of America
| | - Congzhou Wang
- Department of Chemistry, and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York, 12222, United States of America
| | - Li Niu
- Department of Chemistry, and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York, 12222, United States of America
- * E-mail:
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40
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Milić D, Veprintsev DB. Large-scale production and protein engineering of G protein-coupled receptors for structural studies. Front Pharmacol 2015; 6:66. [PMID: 25873898 PMCID: PMC4379943 DOI: 10.3389/fphar.2015.00066] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Accepted: 03/13/2015] [Indexed: 01/26/2023] Open
Abstract
Structural studies of G protein-coupled receptors (GPCRs) gave insights into molecular mechanisms of their action and contributed significantly to molecular pharmacology. This is primarily due to technical advances in protein engineering, production and crystallization of these important receptor targets. On the other hand, NMR spectroscopy of GPCRs, which can provide information about their dynamics, still remains challenging due to difficulties in preparation of isotopically labeled receptors and their low long-term stabilities. In this review, we discuss methods used for expression and purification of GPCRs for crystallographic and NMR studies. We also summarize protein engineering methods that played a crucial role in obtaining GPCR crystal structures.
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Affiliation(s)
- Dalibor Milić
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen Switzerland
| | - Dmitry B Veprintsev
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen Switzerland ; Department of Biology, Eidgenössische Technische Hochschule Zürich, Zürich Switzerland
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41
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Malmerberg E, M Bovee-Geurts PH, Katona G, Deupi X, Arnlund D, Wickstrand C, Johansson LC, Westenhoff S, Nazarenko E, Schertler GFX, Menzel A, de Grip WJ, Neutze R. Conformational activation of visual rhodopsin in native disc membranes. Sci Signal 2015; 8:ra26. [PMID: 25759477 DOI: 10.1126/scisignal.2005646] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Rhodopsin is the G protein-coupled receptor (GPCR) that serves as a dim-light receptor for vision in vertebrates. We probed light-induced conformational changes in rhodopsin in its native membrane environment at room temperature using time-resolved wide-angle x-ray scattering. We observed a rapid conformational transition that is consistent with an outward tilt of the cytoplasmic portion of transmembrane helix 6 concomitant with an inward movement of the cytoplasmic portion of transmembrane helix 5. These movements were considerably larger than those reported from the basis of crystal structures of activated rhodopsin, implying that light activation of rhodopsin involves a more extended conformational change than was previously suggested.
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Affiliation(s)
- Erik Malmerberg
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden
| | - Petra H M Bovee-Geurts
- Department of Biochemistry, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, Netherlands
| | - Gergely Katona
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden
| | - Xavier Deupi
- Condensed Matter Theory Group, Paul Scherrer Institute, CH-5232 Villigen, Switzerland. Laboratory of Biomolecular Research, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - David Arnlund
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden
| | - Cecilia Wickstrand
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden
| | - Linda C Johansson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden
| | - Sebastian Westenhoff
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden
| | - Elena Nazarenko
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden
| | - Gebhard F X Schertler
- Laboratory of Biomolecular Research, Paul Scherrer Institute, CH-5232 Villigen, Switzerland. Department of Biology, ETH Zürich, Wolfgang-Pauli-Str. 27, 8093 Zürich, Switzerland
| | - Andreas Menzel
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - Willem J de Grip
- Department of Biochemistry, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, Netherlands
| | - Richard Neutze
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden.
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42
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Photoactivation-induced instability of rhodopsin mutants T4K and T17M in rod outer segments underlies retinal degeneration in X. laevis transgenic models of retinitis pigmentosa. J Neurosci 2015; 34:13336-48. [PMID: 25274813 DOI: 10.1523/jneurosci.1655-14.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Retinitis pigmentosa (RP) is an inherited neurodegenerative disease involving progressive vision loss, and is often linked to mutations in the rhodopsin gene. Mutations that abolish N-terminal glycosylation of rhodopsin (T4K and T17M) cause sector RP in which the inferior retina preferentially degenerates, possibly due to greater light exposure of this region. Transgenic animal models expressing rhodopsin glycosylation mutants also exhibit light exacerbated retinal degeneration (RD). In this study, we used transgenic Xenopus laevis to investigate the pathogenic mechanism connecting light exposure and RD in photoreceptors expressing T4K or T17M rhodopsin. We demonstrate that increasing the thermal stability of these rhodopsins via a novel disulfide bond resulted in significantly less RD. Furthermore, T4K or T17M rhodopsins that were constitutively inactive (due to lack of the chromophore-binding site or dietary deprivation of the chromophore precursor vitamin A) induced less toxicity. In contrast, variants in the active conformation accumulated in the ER and caused RD even in the absence of light. In vitro, T4K and T17M rhodopsins showed reduced ability to regenerate pigment after light exposure. Finally, although multiple amino acid substitutions of T4 abolished glycosylation at N2 but were not toxic, similar substitutions of T17 were not tolerated, suggesting that the carbohydrate moiety at N15 is critical for cell viability. Our results identify a novel pathogenic mechanism in which the glycosylation-deficient rhodopsins are destabilized by light activation. These results have important implications for proposed RP therapies, such as vitamin A supplementation, which may be ineffective or even detrimental for certain RP genotypes.
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43
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Methodological advances: the unsung heroes of the GPCR structural revolution. Nat Rev Mol Cell Biol 2015; 16:69-81. [DOI: 10.1038/nrm3933] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Abstract
Rhodopsin is a key light-sensitive protein expressed exclusively in rod photoreceptor cells of the retina. Failure to express this transmembrane protein causes a lack of rod outer segment formation and progressive retinal degeneration, including the loss of cone photoreceptor cells. Molecular studies of rhodopsin have paved the way to understanding a large family of cell-surface membrane proteins called G protein-coupled receptors (GPCRs). Work started on rhodopsin over 100 years ago still continues today with substantial progress made every year. These activities underscore the importance of rhodopsin as a prototypical GPCR and receptor required for visual perception-the fundamental process of translating light energy into a biochemical cascade of events culminating in vision.
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Affiliation(s)
- Lukas Hofmann
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH, 44106, USA
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45
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Xiao S, Shiloach J, Grisshammer R. Construction of recombinant HEK293 cell lines for the expression of the neurotensin receptor NTSR1. Methods Mol Biol 2015; 1272:51-64. [PMID: 25563176 DOI: 10.1007/978-1-4939-2336-6_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
G protein-coupled receptors (GPCRs) are associated with a wide array of diseases and are targets of most of the medicines sold worldwide. Despite their clinical importance, only 25 unique GPCR structures have been determined as of April 2014. The first step for structural studies is to establish the expression of correctly folded, functional receptors in recombinant host cells at quantities to allow subsequent purification and crystallization trials. Here we describe the T-REx™-inducible expression system to construct and select a stable HEK293 cell line for high-level expression of functional neurotensin receptor type I (NTSR1). We also present the protocols used for the adaptation of the cells into suspension culture, as well as the optimization of the induction parameters for NTSR1 expression, which led to 1 mg of purified NTSR1 per liter suspension culture in bioreactors.
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Affiliation(s)
- Su Xiao
- Biotechnology Core Laboratory, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
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46
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Seiradake E, Zhao Y, Lu W, Aricescu AR, Jones EY. Production of cell surface and secreted glycoproteins in mammalian cells. Methods Mol Biol 2015; 1261:115-27. [PMID: 25502196 DOI: 10.1007/978-1-4939-2230-7_6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Mammalian protein expression systems are becoming increasingly popular for the production of eukaryotic secreted and cell surface proteins. Here we describe methods to produce recombinant proteins in adherent or suspension human embryonic kidney cell cultures, using transient transfection or stable cell lines. The protocols are easy to scale up and cost-efficient, making them suitable for protein crystallization projects and other applications that require high protein yields.
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Affiliation(s)
- Elena Seiradake
- The Division of Structural Biology, The Henry Wellcome Building for Genomic Medicine, Roosevelt Drive, Oxford, OX3 7BN, UK
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47
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Schonenbach NS, Hussain S, O'Malley MA. Structure and function of G protein‐coupled receptor oligomers: implications for drug discovery. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2014; 7:408-27. [DOI: 10.1002/wnan.1319] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 09/26/2014] [Accepted: 10/11/2014] [Indexed: 12/21/2022]
Affiliation(s)
- Nicole S. Schonenbach
- Department of Chemical EngineeringUniversity of California Santa BarbaraSanta BarbaraCAUSA
| | - Sunyia Hussain
- Department of Chemical EngineeringUniversity of California Santa BarbaraSanta BarbaraCAUSA
| | - Michelle A. O'Malley
- Department of Chemical EngineeringUniversity of California Santa BarbaraSanta BarbaraCAUSA
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48
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Nucleotide bound to rab11a controls localization in rod cells but not interaction with rhodopsin. J Neurosci 2014; 34:14854-63. [PMID: 25378153 DOI: 10.1523/jneurosci.1943-14.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Precise vectorial transport of rhodopsin is essential for rod photoreceptor health and function. Mutations that truncate or extend the C terminus of rhodopsin disrupt this transport, and lead to retinal degeneration and blindness in human patients and in mouse models. Here we show that such mutations disrupt the binding of rhodopsin to the small GTPase rab11a. The rhodopsin-rab11a interaction is a direct binding interaction that does not depend on the nucleotide binding state of rab11a. Expression of EGFP-rab11a fusion proteins in Xenopus laevis photoreceptors revealed that the nucleotide binding status of rab11a affects its subcellular localization, with GTP-locked mutants concentrated in the inner segment and GDP-locked mutants concentrated in the outer segment. shRNA-mediated knockdown of rab11a in rods led to shortened outer segments and retinal degeneration. Together, our results show the critical importance of direct rhodopsin-rab11a interactions for the formation and maintenance of vertebrate photoreceptors.
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49
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Scott CE, Abrol R, Ahn KH, Kendall DA, Goddard WA. Molecular basis for dramatic changes in cannabinoid CB1 G protein-coupled receptor activation upon single and double point mutations. Protein Sci 2014. [PMID: 23184890 DOI: 10.1002/pro.2192] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
There is considerable interest in determining the activation mechanism of G protein-coupled receptors (GPCRs), one of the most important types of proteins for intercellular signaling. Recently, it was demonstrated for the cannabinoid CB1 GPCR, that a single mutation T210A could make CB1 completely inactive whereas T210I makes it essentially constitutively active. To obtain an understanding of this dramatic dependence of activity on mutation, we used first-principles-based methods to predict the ensemble of low-energy seven-helix conformations for the wild-type (WT) and mutants (T210A and T210I). We find that the transmembrane (TM) helix packings depend markedly on these mutations, leading for T210A to both TM3+TM6 and TM2+TM6 salt-bridge couplings in the cytoplasmic face that explains the inactivity of this mutant. In contrast T210I has no such couplings across the receptor explaining the ease in activating this mutant. WT has just the TM3+TM6 coupling, known to be broken upon GPCR activation. To test this hypothesis on activity, we predicted double mutants that would convert the inactive mutant to normal activity and then confirmed this experimentally. This CB1 activation mechanism, or one similar to it, is expected to play a role in other constitutively active GPCRs as well.
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Affiliation(s)
- Caitlin E Scott
- Division of Chemistry and Chemical Engineering, Materials and Process Simulation Center, MC 139-74, California Institute of Technology, Pasadena, California 91125, USA
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50
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Miyaguchi K. Direct imaging electron microscopy (EM) methods in modern structural biology: overview and comparison with X-ray crystallography and single-particle cryo-EM reconstruction in the studies of large macromolecules. Biol Cell 2014; 106:323-45. [PMID: 25040059 DOI: 10.1111/boc.201300081] [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: 11/27/2013] [Accepted: 07/01/2014] [Indexed: 11/28/2022]
Abstract
Determining the structure of macromolecules is important for understanding their function. The fine structure of large macromolecules is currently studied primarily by X-ray crystallography and single-particle cryo-electron microscopy (EM) reconstruction. Before the development of these techniques, macromolecular structure was often examined by negative-staining, rotary-shadowing and freeze-etching EM, which are categorised here as 'direct imaging EM methods'. In this review, the results are summarised by each of the above techniques and compared with respect to four macromolecules: the ryanodine receptor, cadherin, rhodopsin and the ribosome-translocon complex (RTC). The results of structural analysis of the ryanodine receptor and cadherin are consistent between each technique. The results obtained for rhodopsin vary to some extent within each technique and between the different techniques. Finally, the results for RTC are inconsistent between direct imaging EM and other analytical techniques, especially with respect to the space within RTC, the reasons for which are discussed. Then, the role of direct imaging EM methods in modern structural biology is discussed. Direct imaging methods should support and verify the results obtained by other analytical methods capable of solving three-dimensional molecular architecture, and they should still be used as a primary tool for studying macromolecule structure in vivo.
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Affiliation(s)
- Katsuyuki Miyaguchi
- Shinsapporokeiaikai Hospital, 5-5-35 Ooyachihigashi, Atsubetsuku, Sapporo, 004-0041, Japan
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