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Yang LK, Tao YX. Alanine Scanning Mutagenesis of the DRYxxI Motif and Intracellular Loop 2 of Human Melanocortin-4 Receptor. Int J Mol Sci 2020; 21:ijms21207611. [PMID: 33076233 PMCID: PMC7589821 DOI: 10.3390/ijms21207611] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/10/2020] [Accepted: 10/11/2020] [Indexed: 12/15/2022] Open
Abstract
The melanocortin-4 receptor (MC4R) is a member of the G-protein-coupled receptor (GPCR) superfamily, which has been extensively studied in obesity pathogenesis due to its critical role in regulating energy homeostasis. Both the Gs-cAMP and ERK1/2 cascades are known as important intracellular signaling pathways initiated by the MC4R. The DRYxxI motif at the end of transmembrane domain 3 and the intracellular loop 2 (ICL2) are thought to be crucial for receptor function in several GPCRs. To study the functions of this domain in MC4R, we performed alanine-scanning mutagenesis on seventeen residues. We showed that one residue was critical for receptor cell surface expression. Eight residues were important for ligand binding. Mutations of three residues impaired Gs-cAMP signaling without changing the binding properties. Investigation on constitutive activities of all the mutants in the cAMP pathway revealed that six residues were involved in constraining the receptor in inactive states and five residues were important for receptor activation in the absence of an agonist. In addition, mutations of four residues impaired the ligand-stimulated ERK1/2 signaling pathway without affecting the binding properties. We also showed that some mutants were biased to the Gs-cAMP or ERK1/2 signaling pathway. In summary, we demonstrated that the DRYxxI motif and ICL2 were important for MC4R function.
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Saleh N, Kleinau G, Heyder N, Clark T, Hildebrand PW, Scheerer P. Binding, Thermodynamics, and Selectivity of a Non-peptide Antagonist to the Melanocortin-4 Receptor. Front Pharmacol 2018; 9:560. [PMID: 29910730 PMCID: PMC5992272 DOI: 10.3389/fphar.2018.00560] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 05/10/2018] [Indexed: 11/22/2022] Open
Abstract
The melanocortin-4 receptor (MC4R) is a potential drug target for treatment of obesity, anxiety, depression, and sexual dysfunction. Crystal structures for MC4R are not yet available, which has hindered successful structure-based drug design. Using microsecond-scale molecular-dynamics simulations, we have investigated selective binding of the non-peptide antagonist MCL0129 to a homology model of human MC4R (hMC4R). This approach revealed that, at the end of a multi-step binding process, MCL0129 spontaneously adopts a binding mode in which it blocks the agonistic-binding site. This binding mode was confirmed in subsequent metadynamics simulations, which gave an affinity for human hMC4R that matches the experimentally determined value. Extending our simulations of MCL0129 binding to hMC1R and hMC3R, we find that receptor subtype selectivity for hMC4R depends on few amino acids located in various structural elements of the receptor. These insights may support rational drug design targeting the melanocortin systems.
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Affiliation(s)
- Noureldin Saleh
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Institute of Medical Physics and Biophysics, Berlin, Germany.,Computational Modelling and Dynamics of Molecular Complexes, Berlin, Germany
| | - Gunnar Kleinau
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Institute of Medical Physics and Biophysics, Berlin, Germany.,Group Protein X-ray Crystallography and Signal Transduction, Berlin, Germany
| | - Nicolas Heyder
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Institute of Medical Physics and Biophysics, Berlin, Germany.,Group Protein X-ray Crystallography and Signal Transduction, Berlin, Germany
| | - Timothy Clark
- Computer-Chemie-Centrum, Department of Chemistry and Pharmacy, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Peter W Hildebrand
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Institute of Medical Physics and Biophysics, Berlin, Germany.,Computational Modelling and Dynamics of Molecular Complexes, Berlin, Germany.,Institute of Medical Physics and Biophysics, Leipzig University, Leipzig, Germany
| | - Patrick Scheerer
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Institute of Medical Physics and Biophysics, Berlin, Germany.,Group Protein X-ray Crystallography and Signal Transduction, Berlin, Germany
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Pandey A, Shin K, Patterson RE, Liu XQ, Rainey JK. Current strategies for protein production and purification enabling membrane protein structural biology. Biochem Cell Biol 2016; 94:507-527. [PMID: 27010607 PMCID: PMC5752365 DOI: 10.1139/bcb-2015-0143] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Membrane proteins are still heavily under-represented in the protein data bank (PDB), owing to multiple bottlenecks. The typical low abundance of membrane proteins in their natural hosts makes it necessary to overexpress these proteins either in heterologous systems or through in vitro translation/cell-free expression. Heterologous expression of proteins, in turn, leads to multiple obstacles, owing to the unpredictability of compatibility of the target protein for expression in a given host. The highly hydrophobic and (or) amphipathic nature of membrane proteins also leads to challenges in producing a homogeneous, stable, and pure sample for structural studies. Circumventing these hurdles has become possible through the introduction of novel protein production protocols; efficient protein isolation and sample preparation methods; and, improvement in hardware and software for structural characterization. Combined, these advances have made the past 10-15 years very exciting and eventful for the field of membrane protein structural biology, with an exponential growth in the number of solved membrane protein structures. In this review, we focus on both the advances and diversity of protein production and purification methods that have allowed this growth in structural knowledge of membrane proteins through X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and cryo-electron microscopy (cryo-EM).
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Affiliation(s)
- Aditya Pandey
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Kyungsoo Shin
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Robin E. Patterson
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Xiang-Qin Liu
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Jan K. Rainey
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
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Boulton S, Melacini G. Advances in NMR Methods To Map Allosteric Sites: From Models to Translation. Chem Rev 2016; 116:6267-304. [PMID: 27111288 DOI: 10.1021/acs.chemrev.5b00718] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The last five years have witnessed major developments in the understanding of the allosteric phenomenon, broadly defined as coupling between remote molecular sites. Such advances have been driven not only by new theoretical models and pharmacological applications of allostery, but also by progress in the experimental approaches designed to map allosteric sites and transitions. Among these techniques, NMR spectroscopy has played a major role given its unique near-atomic resolution and sensitivity to the dynamics that underlie allosteric couplings. Here, we highlight recent progress in the NMR methods tailored to investigate allostery with the goal of offering an overview of which NMR approaches are best suited for which allosterically relevant questions. The picture of the allosteric "NMR toolbox" is provided starting from one of the simplest models of allostery (i.e., the four-state thermodynamic cycle) and continuing to more complex multistate mechanisms. We also review how such an "NMR toolbox" has assisted the elucidation of the allosteric molecular basis for disease-related mutations and the discovery of novel leads for allosteric drugs. From this overview, it is clear that NMR plays a central role not only in experimentally validating transformative theories of allostery, but also in tapping the full translational potential of allosteric systems.
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Affiliation(s)
- Stephen Boulton
- Department of Chemistry and Chemical Biology Department of Biochemistry and Biomedical Sciences, McMaster University , 1280 Main St. W., Hamilton L8S 4M1, Canada
| | - Giuseppe Melacini
- Department of Chemistry and Chemical Biology Department of Biochemistry and Biomedical Sciences, McMaster University , 1280 Main St. W., Hamilton L8S 4M1, Canada
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Jiang Y, Yuan Y, Zhang X, Liang T, Guo Y, Li M, Pu X. Use of network model to explore dynamic and allosteric properties of three GPCR homodimers. RSC Adv 2016. [DOI: 10.1039/c6ra18243g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We used an elastic network model and protein structure network to study three class A GPCR homodimers.
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Affiliation(s)
- Yuanyuan Jiang
- College of Chemistry
- Sichuan University
- Chengdu
- P. R. China
| | - Yuan Yuan
- College of Management
- Southwest University for Nationalities
- Chengdu 610064
- P. R. China
| | - Xi Zhang
- College of Chemistry
- Sichuan University
- Chengdu
- P. R. China
| | - Tao Liang
- College of Chemistry
- Sichuan University
- Chengdu
- P. R. China
| | - Yanzhi Guo
- College of Chemistry
- Sichuan University
- Chengdu
- P. R. China
| | - Menglong Li
- College of Chemistry
- Sichuan University
- Chengdu
- P. R. China
| | - Xumei Pu
- College of Chemistry
- Sichuan University
- Chengdu
- P. R. China
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