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Jha P, Chaturvedi S, Bhat R, Jain N, Mishra AK. Insights of ligand binding in modeled h5-HT 1A receptor: homology modeling, docking, MM-GBSA, screening and molecular dynamics. J Biomol Struct Dyn 2022; 40:11625-11637. [PMID: 34387135 DOI: 10.1080/07391102.2021.1961865] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The pharmacologically characterized receptor subtype of the serotonin family, the 5HT1A receptor is implicated in the pathophysiology and treatment of depression and anxiety-related disorders. Being the most extensively targeted receptor for developing novel antidepressants and anxiolytics, a near-ideal theoretical model can aid in high-throughput screening of promising drug candidates. However, the design of potential drug candidates suffers owing to a lack of complete structural information. In this work, homology models of 5-HT1A receptor are generated using two distinct alignments (CW and PSTA) and model building methods (KB and EB). The developed models are validated for virtual screening using a ligand dataset of agonists and antagonists. The best-suited model was efficient in discriminating agonist/antagonist binding. Correlation plots between pKi and docking (R2agonist≥ 0.6, R2antagonist≥ 0.7) and MM-GBSA dG bind values (R2agonist≥ 0.5, R2antagonist≥ 0.7) revealed optimum corroboration between in vitro and in silico outcomes, which further suggested the usefulness of the developed model for the design of high-affinity probes for the neurological disorders.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Preeti Jha
- Department of Immunology, Genetics and Pathology, Medical Radiation Science, Rudbeck Laboratory, Uppsala, Sweden.,Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences, Defence Research and Development Organization, Delhi, India.,Department of Chemistry, Indian Institute of Technology Delhi, New Delhi, India
| | - Shubhra Chaturvedi
- Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences, Defence Research and Development Organization, Delhi, India
| | - Ruchika Bhat
- Department of Chemistry, Indian Institute of Technology Delhi, New Delhi, India.,SCFBio, Indian Institute of Technology Delhi, New Delhi, India
| | - Nidhi Jain
- Department of Chemistry, Indian Institute of Technology Delhi, New Delhi, India
| | - Anil K Mishra
- Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences, Defence Research and Development Organization, Delhi, India
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2
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Sullivan HJ, Tursi A, Moore K, Campbell A, Floyd C, Wu C. Binding Interactions of Ergotamine and Dihydroergotamine to 5-Hydroxytryptamine Receptor 1B (5-HT 1b) Using Molecular Dynamics Simulations and Dynamic Network Analysis. J Chem Inf Model 2020; 60:1749-1765. [PMID: 32078320 DOI: 10.1021/acs.jcim.9b01082] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ergotamine (ERG) and dihydroergotamine (DHE), common migraine drugs, have small structural differences but lead to clinically important distinctions in their pharmacological profiles. For example, DHE is less potent than ERG by about 10-fold at the 5-hydroxytrptamine receptor 1B (5-HT1B). Although the high-resolution crystal structures of the 5-HT1B receptor with both ligands have been solved, the high similarity between these two complex structures does not sufficiently explain their activity differences and the activation mechanism of the receptor. Hence, an examination of the dynamic motion of both drugs with the receptor is required. In this study, we ran a total of 6.0 μs molecular dynamics simulations on each system. Our simulation data show the subtle variations between the two systems in terms of the ligand-receptor interactions and receptor secondary structures. More importantly, the ligand and protein root-mean-square fluctuations (RMSFs) for the two systems were distinct, with ERG having a trend of lower RMSF values, indicating it to be bound tighter to 5-HT1B with less fluctuations. The molecular mechanism-general born surface area (MM-GBSA) binding energies illustrate this further, proving ERG has an overall stronger MM-GBSA binding energy. Analysis of several different microswitches has shown that the 5-HT1B-ERG complex is in a more active conformation state than 5-HT1B-DHE, which is further supported by the dynamic network model, with reference to mutagenesis data with the critical nodes and the first three low-energy modes from the normal mode analysis. We also identify Trp3276.48 and Phe3316.52 as key residues involved in the active state 5-HT1B for both ligands. Using the detailed dynamic information from our analysis, we made predictions for possible modifications to DHE and ERG that yielded five derivatives that might have more favorable binding energies and reduced structural fluctuations.
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Affiliation(s)
- Holli-Joi Sullivan
- College of Science and Mathematics, Rowan University, Glassboro, New Jersey 08028 United States
| | - Amanda Tursi
- College of Science and Mathematics, Rowan University, Glassboro, New Jersey 08028 United States
| | - Kelly Moore
- College of Science and Mathematics, Rowan University, Glassboro, New Jersey 08028 United States
| | - Alexandra Campbell
- College of Science and Mathematics, Rowan University, Glassboro, New Jersey 08028 United States
| | - Cecilia Floyd
- College of Science and Mathematics, Rowan University, Glassboro, New Jersey 08028 United States
| | - Chun Wu
- College of Science and Mathematics, Rowan University, Glassboro, New Jersey 08028 United States
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3
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Cao HH, Nakatsuka N, Deshayes S, Abendroth JM, Yang H, Weiss PS, Kasko AM, Andrews AM. Small-Molecule Patterning via Prefunctionalized Alkanethiols. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2018; 30:4017-4030. [PMID: 30828130 PMCID: PMC6393937 DOI: 10.1021/acs.chemmater.8b00377] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Interactions between small molecules and biomolecules are important physiologically and for biosensing, diagnostic, and therapeutic applications. To investigate these interactions, small molecules can be tethered to substrates through standard coupling chemistries. While convenient, these approaches co-opt one or more of the few small-molecule functional groups needed for biorecognition. Moreover, for multiplexing, individual probes require different surface functionalization chemistries, conditions, and/or protection/deprotection strategies. Thus, when placing multiple small-molecules on surfaces, orthogonal chemistries are needed that preserve all functional groups and are sequentially compatible. Here, we approach high-fidelity small-molecule patterning by coupling small-molecule neurotransmitter precursors, as examples, to monodisperse asymmetric oligo(ethylene glycol)alkanethiols during synthesis and prior to self-assembly on Au substrates. We use chemical lift-off lithography to singly and doubly pattern substrates. Selective antibody recognition of pre-functionalized thiols was comparable to or better than recognition of small molecules functionalized to alkanethiols after surface assembly. These findings demonstrate that synthesis and patterning approaches that circumvent sequential surface conjugation chemistries enable biomolecule recognition and afford gateways to multiplexed small-molecule functionalized substrates.
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Affiliation(s)
- Huan H. Cao
- Department of Chemistry and Biochemistry, University of
California, Los Angeles, Los Angeles, CA 90095, United States
- California NanoSystems Institute, University of California,
Los Angeles, Los Angeles, CA 90095, United States
| | - Nako Nakatsuka
- Department of Chemistry and Biochemistry, University of
California, Los Angeles, Los Angeles, CA 90095, United States
- California NanoSystems Institute, University of California,
Los Angeles, Los Angeles, CA 90095, United States
| | - Stephanie Deshayes
- Department of Bioengineering, University of California, Los
Angeles, Los Angeles, CA 90095, United States
| | - John M. Abendroth
- Department of Chemistry and Biochemistry, University of
California, Los Angeles, Los Angeles, CA 90095, United States
- California NanoSystems Institute, University of California,
Los Angeles, Los Angeles, CA 90095, United States
| | - Hongyan Yang
- Department of Psychiatry and Biobehavioral Sciences, Semel
Institute for Neuroscience and Human Behavior, and Hatos Center for
Neuropharmacology, David Geffen School of Medicine, University of California, Los
Angeles, Los Angeles, CA 90095, United States
| | - Paul S. Weiss
- Department of Chemistry and Biochemistry, University of
California, Los Angeles, Los Angeles, CA 90095, United States
- California NanoSystems Institute, University of California,
Los Angeles, Los Angeles, CA 90095, United States
- Department of Materials Science and Engineering, University
of California, Los Angeles, Los Angeles, CA 90095, United States
- Corresponding Authors, , or
| | - Andrea M. Kasko
- California NanoSystems Institute, University of California,
Los Angeles, Los Angeles, CA 90095, United States
- Department of Bioengineering, University of California, Los
Angeles, Los Angeles, CA 90095, United States
- Corresponding Authors, , or
| | - Anne M. Andrews
- Department of Chemistry and Biochemistry, University of
California, Los Angeles, Los Angeles, CA 90095, United States
- California NanoSystems Institute, University of California,
Los Angeles, Los Angeles, CA 90095, United States
- Department of Psychiatry and Biobehavioral Sciences, Semel
Institute for Neuroscience and Human Behavior, and Hatos Center for
Neuropharmacology, David Geffen School of Medicine, University of California, Los
Angeles, Los Angeles, CA 90095, United States
- Corresponding Authors, , or
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4
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Abstract
Advances in the structural biology of G-protein Coupled Receptors have resulted in a significant step forward in our understanding of how this important class of drug targets function at the molecular level. However, it has also become apparent that they are very dynamic molecules, and moreover, that the underlying dynamics is crucial in shaping the response to different ligands. Molecular dynamics simulations can provide unique insight into the dynamic properties of GPCRs in a way that is complementary to many experimental approaches. In this chapter, we describe progress in three distinct areas that are particularly difficult to study with other techniques: atomic level investigation of the conformational changes that occur when moving between the various states that GPCRs can exist in, the pathways that ligands adopt during binding/unbinding events and finally, the influence of lipids on the conformational dynamics of GPCRs.
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Affiliation(s)
- Naushad Velgy
- Department of Biochemistry, Structural Bioinformatics and Computational Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - George Hedger
- Department of Biochemistry, Structural Bioinformatics and Computational Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Philip C Biggin
- Department of Biochemistry, Structural Bioinformatics and Computational Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
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5
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Warszycki D, Rueda M, Mordalski S, Kristiansen K, Satała G, Rataj K, Chilmonczyk Z, Sylte I, Abagyan R, Bojarski AJ. From Homology Models to a Set of Predictive Binding Pockets-a 5-HT 1A Receptor Case Study. J Chem Inf Model 2017; 57:311-321. [PMID: 28055203 PMCID: PMC5361891 DOI: 10.1021/acs.jcim.6b00263] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Despite its remarkable importance in the arena of drug design, serotonin 1A receptor (5-HT1A) has been elusive to the X-ray crystallography community. This lack of direct structural information not only hampers our knowledge regarding the binding modes of many popular ligands (including the endogenous neurotransmitter-serotonin), but also limits the search for more potent compounds. In this paper we shed new light on the 3D pharmacological properties of the 5-HT1A receptor by using a ligand-guided approach (ALiBERO) grounded in the Internal Coordinate Mechanics (ICM) docking platform. Starting from a homology template and set of known actives, the method introduces receptor flexibility via Normal Mode Analysis and Monte Carlo sampling, to generate a subset of pockets that display enriched discrimination of actives from inactives in retrospective docking. Here, we thoroughly investigated the repercussions of using different protein templates and the effect of compound selection on screening performance. Finally, the best resulting protein models were applied prospectively in a large virtual screening campaign, in which two new active compounds were identified that were chemically distinct from those described in the literature.
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Affiliation(s)
- Dawid Warszycki
- Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343 Kraków, Poland
| | - Manuel Rueda
- University of California, San Diego, Skaggs School of Pharmacy & Pharmaceutical Sciences, 9500 Gilman Drive, MC 0747 La Jolla, CA 92093-0747, U.S
| | - Stefan Mordalski
- Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343 Kraków, Poland
| | - Kurt Kristiansen
- Department of Medical Biology, Faculty of Health Sciences, University of Tromsø, N-9037 Tromsø, Norway
| | - Grzegorz Satała
- Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343 Kraków, Poland
| | - Krzysztof Rataj
- Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343 Kraków, Poland
| | - Zdzisław Chilmonczyk
- Department of Cell Biology, National Medicines Institute, 30/34 Chełmska Street, 00-725 Warszawa, Poland
| | - Ingebrigt Sylte
- Department of Medical Biology, Faculty of Health Sciences, University of Tromsø, N-9037 Tromsø, Norway
| | - Ruben Abagyan
- University of California, San Diego, Skaggs School of Pharmacy & Pharmaceutical Sciences, 9500 Gilman Drive, MC 0747 La Jolla, CA 92093-0747, U.S
| | - Andrzej J. Bojarski
- Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343 Kraków, Poland
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6
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7
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Fanelli F, De Benedetti PG. Update 1 of: computational modeling approaches to structure-function analysis of G protein-coupled receptors. Chem Rev 2011; 111:PR438-535. [PMID: 22165845 DOI: 10.1021/cr100437t] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Francesca Fanelli
- Dulbecco Telethon Institute, University of Modena and Reggio Emilia, via Campi 183, 41125 Modena, Italy.
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8
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Vaish A, Shuster MJ, Cheunkar S, Singh YS, Weiss PS, Andrews AM. Native serotonin membrane receptors recognize 5-hydroxytryptophan-functionalized substrates: enabling small-molecule recognition. ACS Chem Neurosci 2010; 1:495-504. [PMID: 22778841 PMCID: PMC3368647 DOI: 10.1021/cn1000205] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 03/21/2010] [Indexed: 12/27/2022] Open
Abstract
Recognition of small diffusible molecules by large biomolecules is ubiquitous in biology. To investigate these interactions, it is important to be able to immobilize small ligands on substrates; however, preserving recognition by biomolecule-binding partners under these circumstances is challenging. We have developed methods to modify substrates with serotonin, a small-molecule neurotransmitter important in brain function and psychiatric disorders. To mimic soluble serotonin, we attached its amino acid precursor, 5-hydroxytryptophan, via the ancillary carboxyl group to oligo(ethylene glycol)-terminated alkanethiols self-assembled on gold. Anti-5-hydroxytryptophan antibodies recognize these substrates, demonstrating bioavailability. Interestingly, 5-hydroxytryptophan-functionalized surfaces capture membrane-associated serotonin receptors enantiospecifically. By contrast, surfaces functionalized with serotonin itself fail to bind serotonin receptors. We infer that recognition by biomolecules evolved to distinguish small-molecule ligands in solution requires tethering of the latter via ectopic moieties. Membrane proteins, which are notoriously difficult to isolate, or other binding partners can be captured for identification, mapping, expression, and other purposes using this generalizable approach.
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Affiliation(s)
| | | | | | | | - Paul S. Weiss
- Department of Physics
- Department of Chemistry
- Huck Institutes of the Life Sciences
- Departments of Chemistry and Biochemistry
- California NanoSystems Institute
| | - Anne M. Andrews
- Department of Chemistry
- Department of Veterinary & Biomedical Sciences
- Huck Institutes of the Life Sciences
- Department of Psychiatry
- California NanoSystems Institute
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9
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Cozzini P, Kellogg GE, Spyrakis F, Abraham DJ, Costantino G, Emerson A, Fanelli F, Gohlke H, Kuhn LA, Morris GM, Orozco M, Pertinhez TA, Rizzi M, Sotriffer CA. Target flexibility: an emerging consideration in drug discovery and design. J Med Chem 2008; 51:6237-55. [PMID: 18785728 DOI: 10.1021/jm800562d] [Citation(s) in RCA: 206] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Pietro Cozzini
- Department of General and Inorganic Chemistry, University of Parma, Via G.P. Usberti 17/A 43100, Parma,
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10
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Kołaczkowski M, Nowak M, Pawłowski M, Bojarski AJ. Receptor-based pharmacophores for serotonin 5-HT7R antagonists-implications to selectivity. J Med Chem 2007; 49:6732-41. [PMID: 17154504 DOI: 10.1021/jm060300c] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A set of 31 diversified 5-HT7 receptor antagonists was automatically docked to a conformational ensemble of rhodopsin-based 5-HT7R models (flexible docking). It was found that ergolines, aporphines, and tricyclic psychotropic agents were always docked in a pocket formed by TMHs 4-6, and besides the main ionic bond with Asp3.32, they had specific interactions with Phe6.52, Phe6.51, Trp6.48, and Ser5.42. The arylpiperidine, arylpiperazine, or beta-carboline fragment of the complex ligands occupied the same pocket, whereas the terminal amide/imide part of those compounds reached the second cavity formed by TMHs 7-3 and interacted with Phe3.28, Arg7.36, and Tyr7.43. A similar orientation of selective antagonists of the group of arylsulfonamidoalkylamines was observed, that is, the sulfonamide part was located in the second pocket. Coherent docking results allowed the generation of two receptor-based pharmacophores: first containing features necessary for high 5-HT7R affinity and the other defining selectivity for this receptor subtype. The latter model indicated the importance of specific interactions with the residues of the TMHs 7-3 pocket (especially nonconserved Arg7.36) for selectivity over other monoamine GPCRs.
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Affiliation(s)
- Marcin Kołaczkowski
- Department of Medicinal Chemistry, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.
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11
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Fanelli F, De Benedetti PG. Inactive and active states and supramolecular organization of GPCRs: insights from computational modeling. J Comput Aided Mol Des 2006; 20:449-61. [PMID: 17009093 DOI: 10.1007/s10822-006-9064-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Accepted: 08/04/2006] [Indexed: 10/24/2022]
Abstract
Herein we make an overview of the results of our computational experiments aimed at gaining insight into the molecular mechanisms of GPCR functioning either in their normal conditions or when hit by gain-of-function or loss-of-function mutations. Molecular simulations of a number of GPCRs in their wild type and mutated as well as free and ligand-bound forms were instrumental in inferring the structural features, which differentiate the mutation- and ligand-induced active from the inactive states. These features essentially reside in the interaction pattern of the E/DRY arginine and in the degree of solvent exposure of selected cytosolic domains. Indeed, the active states differ from the inactive ones in the weakening of the interactions made by the highly conserved arginine and in the increase in solvent accessibility of the cytosolic interface between helices 3 and 6. Where possible, the structural hallmarks of the active and inactive receptor states are translated into molecular descriptors useful for in silico functional screening of novel receptor mutants or ligands. Computational modeling of the supramolecular organization of GPCRs and their intracellular partners is the current challenge toward a deep understanding of their functioning mechanisms.
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Affiliation(s)
- Francesca Fanelli
- Dulbecco Telethon Institute, University of Modena and Reggio Emilia, Via Campi 183, 41100 Modena, Italy.
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12
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Mamputha S, Lu ZL, Roeske RW, Millar RP, Katz AA, Flanagan CA. Conserved amino acid residues that are important for ligand binding in the type I gonadotropin-releasing hormone (GnRH) receptor are required for high potency of GnRH II at the type II GnRH receptor. Mol Endocrinol 2006; 21:281-92. [PMID: 16973761 DOI: 10.1210/me.2006-0150] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
GnRH I regulates reproduction. A second form, designated GnRH II, selectively binds type II GnRH receptors. Amino acids of the type I GnRH receptor required for binding of GnRH I (Asp2.61(98), Asn2.65(102), and Lys3.32(121)) are conserved in the type II GnRH receptor, but their roles in receptor function are unknown. We have delineated their functions using mutagenesis, signaling and binding assays, immunoblotting, and computational modeling. Mutating Asp2.61(97) to Glu or Ala, Asn2.65(101) to Ala, or Lys3.32(120) to Gln decreased potency of GnRH II-stimulated inositol phosphate production. Consistent with proposed roles in ligand recognition, mutations eliminated measurable binding of GnRH II, whereas expression of mutant receptors was not decreased. In detailed analysis of how these residues affect ligand-dependent signaling, [Trp2]-GnRH I showed lesser decreases in potency than GnRH I at the Asp2.61(97)Glu mutant. In contrast, [Trp2]-GnRH II showed the same loss of potency as GnRH II at this mutant. This suggests that Asp2.61(97) contributes to recognition of His2 of GnRH I, but not of GnRH II. GnRH II showed a large decrease in potency at the Asn2.65(101)Ala mutant compared with analogs lacking the CO group of Gly10NH2. This suggests that Asn2.65(101) recognizes Gly10NH2 of GnRH II. GnRH agonists showed large decreases in potency at the Lys3.32(120)Gln mutant, but antagonist activity was unaffected. This suggests that Lys3.32(120) recognizes agonists, but not antagonists, as in the type I receptor. These data indicate that roles of conserved residues are similar, but not identical, in the type I and II GnRH receptors.
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Affiliation(s)
- Sipho Mamputha
- Medical Research Council/University of Cape Town Research Group for Receptor Biology, Institute for Infectious Diseases and Molecular Medicine and Division of Medical Biochemistry, Cape Town, South Africa
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13
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Thiagaraj HV, Ortiz TC, Devereaux MC, Seaver B, Hall B, Parker KK. Regulation of G proteins by human 5-HT1a receptor TM3/i2 and TM5/i3 loop peptides. Neurochem Int 2006; 50:109-18. [PMID: 16973243 DOI: 10.1016/j.neuint.2006.07.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Accepted: 07/11/2006] [Indexed: 12/15/2022]
Abstract
A bioactive synthetic 11 amino acid peptide probe (P11) was constructed according to the published sequence of the human 5HT1a receptor. The probe was used to enhance understanding of cytoplasmic loop 2/G protein coupling and activation. Additionally, two peptides (P8, P9) from the cytoplasmic loop 3 region were synthesized and studied. These probes were tested in a model system of human 5HT1a receptor stably expressed in Chinese Hamster Ovary cells. In agonist inhibition studies, P11 was active in all three receptor preparations tested: whole cells, membrane bound, and solubilized. In analyses of the membrane bound receptor system, P11 demonstrated uncompetitive inhibition characteristics. When forskolin-stimulated cAMP levels were measured, P11 was inactive in this negatively coupled system. Utilizing a [35S]gamma-S-GTP incorporation assay, P11 was unable to stimulate G protein incorporation of GTP. While P8 and P9 were also broadly active as non-competitive agonist inhibitors, their characteristics differed in the signal transduction system. P8 and P9 did not significantly change forskolin-stimulated cAMP levels. However, P8 increased [35S]gamma-S-GTP incorporation, while P9 decreased incorporation. Thus, P11, a synthetic peptide from the TM3/i2 region of the receptor, provides suggestive evidence that this receptor region is involved in G protein coupling but not activation. On the other hand, P8 and P9 activities suggest that the TM5/i3 region is involved in both coupling to and regulation of G protein activity. The current evidence from these cytoplasmic loop regions is discussed in the overall context of an emerging model for human 5HT1a receptor-G protein interactions.
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Affiliation(s)
- Harish V Thiagaraj
- Department of Biomedical and Pharmaceutical Sciences (MPH I02), Skaggs School of Pharmacy, The University of Montana, 32 Campus Drive #1552, Missoula, MT 59812-1552, United States
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14
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Zlatović MV, Sukalović VV, Schneider C, Roglić GM. Interaction of arylpiperazine ligands with the hydrophobic part of the 5-HT1A receptor binding site. Bioorg Med Chem 2006; 14:2994-3001. [PMID: 16403641 DOI: 10.1016/j.bmc.2005.12.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2005] [Revised: 12/04/2005] [Accepted: 12/09/2005] [Indexed: 11/23/2022]
Abstract
A flexible docking of a series of arylpiperazine derivatives with structurally different aryl part to the binding site of a model of human 5-HT1A receptor was exercised. The influence of structure and hydrophobic properties of aryl moiety on binding affinities was discussed and a model for ligand binding in the hydrophobic part of the binding site was proposed.
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Affiliation(s)
- Mario V Zlatović
- Faculty of Chemistry, University of Belgrade, PO Box 158, 11000 Belgrade, Serbia and Montenegro.
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15
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Nowak M, Kołaczkowski M, Pawłowski M, Bojarski AJ. Homology modeling of the serotonin 5-HT1A receptor using automated docking of bioactive compounds with defined geometry. J Med Chem 2006; 49:205-14. [PMID: 16392805 DOI: 10.1021/jm050826h] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper describes a rhodopsin-based model of 5-HT(1A) serotonin receptor. The flexibility of the receptor was considered by using large number of models for ligand dockings. Rearrangements of the heptahelical bundle were introduced, which resulted in the improvement of correlation between computational results and experimental data. The model was validated by automated docking of conformationally restricted arylpiperazines. Specific interactions, responsible for the recognition of arylpiperazine derivatives, were identified. An ionic bond was formed between the protonated amine of ligands and Asp3.32. The aromatic moiety and its substituents specifically interacted with Phe6.52 and Ser5.42, respectively, while the carbonyl groups of imide part of ligands formed hydrogen bonds with Asn7.39 and Tyr7.43. The model reproduced the binding affinity of the test group of ligands (correlation r = 0.8 between pK(i) and docking score). It also gave the enrichment in virtual screening-like experiment (100 compounds), in which 34 high-affinity compounds were found among 50 top-scored ligands.
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Affiliation(s)
- Mateusz Nowak
- Department of Medicinal Chemistry, Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343 Kraków, Poland.
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16
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Favre N, Fanelli F, Missotten M, Nichols A, Wilson J, di Tiani M, Rommel C, Scheer A. The DRY motif as a molecular switch of the human oxytocin receptor. Biochemistry 2005; 44:9990-10008. [PMID: 16042376 DOI: 10.1021/bi0509853] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The human oxytocin receptor is known to exhibit promiscuous activity by coupling to both Galpha(q) and Galpha(i) G proteins to activate distinct signaling pathways. A single-amino acid substitution within the highly conserved E/DRY motif at the cytosolic extension of helix 3 [i.e., D136(3.49)N] increased the rate of both basal and agonist-stimulated inositol phosphate (IP(3)) accumulation of the receptor. Furthermore, like for a typical constitutively active receptor, the partial agonist arginine vasopressin behaved as a full agonist for the D136(3.49)N mutant. Subsequently, both oxytocin and arginine vasopressin showed an increased potency in stimulating IP3 accumulation as compared to the wild-type receptor. Very interestingly, our experiments provide strong evidence that the D136(3.49)N mutant inhibits receptor signaling via Galpha(i)-mediated pathways while increasing the activity through the Galpha(q)-mediated pathways. Molecular simulations of the free and OT-bound forms of wild-type OTR and of the D136(3.49)N constitutively active mutant suggest that the receptor portions close to the E/DRY and NPxxY motifs are particularly susceptible to undergoing structural modification in response to activating mutations and agonist binding. Furthermore, computational modeling suggests that the OT-bound form of wild-type OTR is able to explore more states than the OT-bound form of the D136(3.49)N constitutively active mutant, consistent with its G protein promiscuity. Taken together, these observations emphasize the important role of the E/DRY motif not only in receptor activation but also in the promiscuity of G protein coupling. Knowledge of the mechanism of selective G protein coupling could aid drug discovery efforts to identify signaling specific therapies.
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Affiliation(s)
- Nicolas Favre
- Serono Pharmaceutical Research Institute, 14, Ch. des Aulx, 1228 Plan-les-Ouates, Geneva, Switzerland
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17
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Fanelli F, De Benedetti PG. Computational Modeling Approaches to Structure−Function Analysis of G Protein-Coupled Receptors. Chem Rev 2005; 105:3297-351. [PMID: 16159154 DOI: 10.1021/cr000095n] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Francesca Fanelli
- Dulbecco Telethon Institute and Department of Chemistry, University of Modena and Reggio Emilia, via Campi 183, 41100 Modena, Italy.
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18
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Fiorino F, Perissutti E, Severino B, Santagada V, Cirillo D, Terracciano S, Massarelli P, Bruni G, Collavoli E, Renner C, Caliendo G. New 5-Hydroxytryptamine1A Receptor Ligands Containing a Norbornene Nucleus: Synthesis and in Vitro Pharmacological Evaluation. J Med Chem 2005; 48:5495-503. [PMID: 16107148 DOI: 10.1021/jm050246k] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
New arylpiperazine derivatives were prepared to identify highly selective and potent ligands for the 5-hydroxytryptamine 1A (5-HT(1A)) receptor as potential pharmacological tools in studies of central nervous system (CNS) disorders. The combination of structural elements (heterocyclic nucleus, oxyalkyl chain, and arylpiperazine) known to introduce 5-HT(1A) receptor affinity and the proper selection of substituents led to compounds with higher receptor specificity and affinity. In binding studies, several molecules showed affinity in the nanomolar and subnanomolar ranges at 5-HT(1A) and moderate to no affinity for other relevant receptors (5-HT(2A), 5-HT(2C), D(1), D(2), alpha(1), and alpha(2)). The 4-[3-[4-(o-methoxyphenyl)piperazin-1-yl]propoxy]-4-aza-tricyclo[5.2.1.02,6]dec-8-ene-3,5-dione, with K(i) = 0.021 nM, was the most active and selective derivative for the 5-HT(1A) receptor with respect to other serotonin receptors, whereas the most selective derivative for dopaminergic and adrenergic receptors was a CF(3)-substituted arylpiperazine. As a general trend, compounds with a piperazinylpropoxy chain showed a preferential affinity for the 5-HT(1A) receptor, suggesting that the alkyl chain length represents a critical structural feature in determining 5-HT(1A) receptor affinity and selectivity, as confirmed by the molecular modeling invoked for explaining the differential binding affinities of the new arylpiperazines.
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MESH Headings
- Animals
- Binding Sites
- Brain/metabolism
- Heterocyclic Compounds, 3-Ring/chemical synthesis
- Heterocyclic Compounds, 3-Ring/chemistry
- Heterocyclic Compounds, 3-Ring/pharmacology
- In Vitro Techniques
- Male
- Models, Molecular
- Norbornanes/chemical synthesis
- Norbornanes/chemistry
- Norbornanes/pharmacology
- Piperazines/chemical synthesis
- Piperazines/chemistry
- Piperazines/pharmacology
- Radioligand Assay
- Rats
- Rats, Sprague-Dawley
- Receptor, Serotonin, 5-HT1A/chemistry
- Receptor, Serotonin, 5-HT1A/metabolism
- Receptor, Serotonin, 5-HT2A/metabolism
- Receptor, Serotonin, 5-HT2C/metabolism
- Receptors, Adrenergic, alpha-1/metabolism
- Receptors, Adrenergic, alpha-2/metabolism
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D2/metabolism
- Structure-Activity Relationship
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Affiliation(s)
- Ferdinando Fiorino
- Dipartimento di Chimica Farmaceutica e Tossicologica, Università di Napoli "Federico II", Via D. Montesano 49, 80131 Napoli, Italy
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19
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Ambrosio C, Molinari P, Fanelli F, Chuman Y, Sbraccia M, Ugur O, Costa T. Different structural requirements for the constitutive and the agonist-induced activities of the beta2-adrenergic receptor. J Biol Chem 2005; 280:23464-74. [PMID: 15845544 DOI: 10.1074/jbc.m502901200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We converted Ser-207, located in helix 5 of the beta2-adrenergic receptor, into all other natural amino acids. To quantify receptor activation as a receptor number-independent parameter and directly related to G(s) activation, we expressed the mutants in a G alpha(s)-tethered form. GTP exchange in such constructs is restricted to the fused alpha-subunit and is a linear function of the receptor concentration. Except S207R, all other mutants were expressed to a suitable level for investigation. All mutations reduced the binding affinities of the catechol agonists, epinephrine and isoproterenol, and the extent of reduction was unrelated to the residue ability to form hydrogen bonds. Instead, both enhancements and reductions of affinity were observed for the partial agonist halostachin and the antagonist pindolol. The mutations also enhanced and diminished ligand-induced receptor activation, but the effects were strictly ligand-specific. Polar residues such as Asp and His exalted the activation by full agonists but suppressed that induced by the partial agonists halostachin and dichloroisoproterenol. In contrast, hydrophobic residues such as Ile and Val augmented partial agonist activation. Only Ile and Lys produced a significant increase of constitutive activity. The effects on binding and activity were not correlated, nor did such parameters show any clear correlation with up to 78 descriptors of amino acid physicochemical properties. Our data question the idea that Ser-207 is exposed to the polar crevice in the unbound receptor. They also suggest that the active receptor form induced by a full agonist might be substantially different from that caused by constitutive activation.
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Affiliation(s)
- Caterina Ambrosio
- Department of Pharmacology, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy
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20
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Recent Advances in Selective Serotonergic Agents. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2005. [DOI: 10.1016/s0065-7743(05)40002-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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21
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Leonardi A, Barlocco D, Montesano F, Cignarella G, Motta G, Testa R, Poggesi E, Seeber M, De Benedetti PG, Fanelli F. Synthesis, screening, and molecular modeling of new potent and selective antagonists at the alpha 1d adrenergic receptor. J Med Chem 2004; 47:1900-18. [PMID: 15055991 DOI: 10.1021/jm030944+] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the present study, more than 75 compounds structurally related to BMY 7378 have been designed and synthesized. Structural variations of each part of the reference molecule have been introduced, obtaining highly selective ligands for the alpha(1d) adrenergic receptor. The molecular determinants for selectivity at this receptor are essentially held by the phenyl substituent in the phenylpiperazine moiety. The integration of an extensive SAR analysis with docking simulations using the rhodopsin-based models of the three alpha(1)-AR subtypes and of the 5-HT(1A) receptor provides significant insights into the characterization of the receptor binding sites as well as into the molecular determinants of ligand selectivity at the alpha(1d)-AR and the 5-HT(1A) receptors. The results of multiple copies simultaneous search (MCSS) on the substituted phenylpiperazines together with those of manual docking of compounds BMY 7378 and 69 into the putative binding sites of the alpha(1a)-AR, alpha(1b)-AR, alpha(1d)-AR, and the 5-HT(1A) receptors suggest that the phenylpiperazine moiety would dock into a site formed by amino acids in helices 3, 4, 5, 6 and extracellular loop 2 (E2), whereas the spirocyclic ring of the ligand docks into a site formed by amino acids of helices 1, 2, 3, and 7. This docking mode is consistent with the SAR data produced in this work. Furthermore, the binding site of the imide moiety does not allow for the simultaneous involvement of the two carbonyl oxygen atoms in H-bonding interactions, consistent with the SAR data, in particular with the results obtained with the lactam derivative 128. The results of docking simulations also suggest that the second and third extracellular loops may act as selectivity filters for the substituted phenylpiperazines. The most potent and selective compounds for alpha(1d) adrenergic receptor, i.e., 69 (Rec 26D/038) and 128 (Rec 26D/073), are characterized by the presence of the 2,5-dichlorophenylpiperazine moiety.
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MESH Headings
- Adrenergic alpha-1 Receptor Antagonists
- Adrenergic alpha-Antagonists/chemical synthesis
- Adrenergic alpha-Antagonists/chemistry
- Adrenergic alpha-Antagonists/pharmacology
- Amino Acid Sequence
- Animals
- Binding Sites
- CHO Cells
- Cricetinae
- Guinea Pigs
- HeLa Cells
- Humans
- Imides/chemical synthesis
- Imides/chemistry
- Imides/pharmacology
- In Vitro Techniques
- Ligands
- Male
- Models, Molecular
- Molecular Sequence Data
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Protein Structure, Tertiary
- Radioligand Assay
- Rats
- Rats, Sprague-Dawley
- Receptor, Serotonin, 5-HT1A/metabolism
- Receptors, Adrenergic, alpha-1/chemistry
- Receptors, Adrenergic, alpha-1/metabolism
- Sequence Alignment
- Serotonin 5-HT1 Receptor Antagonists
- Spiro Compounds/chemical synthesis
- Spiro Compounds/chemistry
- Spiro Compounds/pharmacology
- Structure-Activity Relationship
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Affiliation(s)
- Amedeo Leonardi
- Pharmaceutical R & D Division, Recordati s.p.a., Via Civitali 1, 20148 Milan, Italy.
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22
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Vitale RM, Pedone C, De Benedetti PG, Fanelli F. Structural features of the inactive and active states of the melanin-concentrating hormone receptors: Insights from molecular simulations. Proteins 2004; 56:430-48. [PMID: 15229878 DOI: 10.1002/prot.20125] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Comparative molecular dynamics simulations of both subtypes 1 and 2 of the melanin-concentrating hormone receptor (MCHR1 and MCHR2, respectively) in their free and hormone-bound forms have been carried out. The hormone has been used in its full-length and truncated forms, as well as in 16 mutated forms. Moreover, MCHR1 has been simulated in complex with T-226296, a novel orally active and selective antagonist. The comparative analysis of an extended number of receptor configurations suggests that the differences between inactive (i.e., free and antagonist-bound) and active (i.e., agonist-bound) states of MCHRs involve the receptor portions close to the E/DRY and NPxxY motifs, with prominence to the cytosolic extensions of helices 2, 3, 6, and 7. In fact, the active forms of these receptors share the release of selected intramolecular interactions found in the inactive forms, such as that between R3.50 of the E/DRY motif and D2.40, and that between Y7.53 of the NPxxY motif and F7.60. Another feature of the active forms of both MCHRs is the approach of "helix 8" to the cytosolic extension of helix 3. These features of the active forms are concurrent with the opening of a cleft at the cytosolic end of the helix bundle. For both MCHRs, the agonist-induced chemical information transfer from the extracellular to the cytosolic domains is mediated by a cluster of aromatic amino acids in helix 6, following the ligand interaction with selected amino acids in the extracellular half of the receptor.
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MESH Headings
- Amino Acid Motifs
- Amino Acid Sequence
- Binding Sites
- Biphenyl Compounds/metabolism
- Chemical Phenomena
- Chemistry, Physical
- Computer Simulation
- Hydrogen Bonding
- Hypothalamic Hormones/chemistry
- Hypothalamic Hormones/metabolism
- Ligands
- Melanins/chemistry
- Melanins/metabolism
- Models, Chemical
- Molecular Sequence Data
- Naphthalenes/metabolism
- Peptide Fragments/chemistry
- Pituitary Hormones/chemistry
- Pituitary Hormones/metabolism
- Protein Conformation
- Protein Structure, Secondary
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Pituitary Hormone/antagonists & inhibitors
- Receptors, Pituitary Hormone/chemistry
- Receptors, Pituitary Hormone/metabolism
- Receptors, Somatostatin/chemistry
- Rhodopsin/chemistry
- Sequence Deletion
- Sequence Homology, Amino Acid
- Thermodynamics
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Affiliation(s)
- Rosa Maria Vitale
- Department of Chemistry, University of Modena and Reggio Emilia, Modena, Italy
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