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Sarma H, Upadhyaya M, Gogoi B, Phukan M, Kashyap P, Das B, Devi R, Sharma HK. Cardiovascular Drugs: an Insight of In Silico Drug Design Tools. J Pharm Innov 2021. [DOI: 10.1007/s12247-021-09587-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Erol I, Cosut B, Durdagi S. Toward Understanding the Impact of Dimerization Interfaces in Angiotensin II Type 1 Receptor. J Chem Inf Model 2019; 59:4314-4327. [PMID: 31429557 DOI: 10.1021/acs.jcim.9b00294] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Angiotensin II type 1 receptor (AT1R) is a prototypical class A G protein-coupled receptor (GPCR) that has an important role in cardiovascular pathologies and blood pressure regulation as well as in the central nervous system. GPCRs may exist and function as monomers; however, they can assemble to form higher order structures, and as a result of oligomerization, their function and signaling profiles can be altered. In the case of AT1R, the classical Gαq/11 pathway is initiated with endogenous agonist angiotensin II binding. A variety of cardiovascular pathologies such as heart failure, diabetic nephropathy, atherosclerosis, and hypertension are associated with this pathway. Recent findings reveal that AT1R can form homodimers and activate the noncanonical (β-arrestin-mediated) pathway. Nevertheless, the exact dimerization interface and atomic details of AT1R homodimerization have not been still elucidated. Here, six different symmetrical dimer interfaces of AT1R are considered, and homodimers were constructed using other published GPCR crystal dimer interfaces as template structures. These AT1R homodimers were then inserted into the model membrane bilayers and subjected to all-atom molecular dynamics simulations. Our simulation results along with the principal component analysis and water pathway analysis suggest four different interfaces as the most plausible: symmetrical transmembrane (TM)1,2,8; TM5; TM4; and TM4,5 AT1R dimer interfaces that consist of one inactive and one active protomer. Moreover, we identified ILE2386.33 as a hub residue in the stabilization of the inactive state of AT1R.
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Affiliation(s)
- Ismail Erol
- Department of Chemistry , Gebze Technical University , Gebze 41400 , Kocaeli , Turkey
| | - Bunyemin Cosut
- Department of Chemistry , Gebze Technical University , Gebze 41400 , Kocaeli , Turkey
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Takezako T, Unal H, Karnik SS, Node K. The non-biphenyl-tetrazole angiotensin AT 1 receptor antagonist eprosartan is a unique and robust inverse agonist of the active state of the AT 1 receptor. Br J Pharmacol 2018; 175:2454-2469. [PMID: 29570771 PMCID: PMC5980637 DOI: 10.1111/bph.14213] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 02/26/2018] [Accepted: 03/06/2018] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND PURPOSE Conditions such as hypertension and renal allograft rejection are accompanied by chronic, agonist-independent, signalling by angiotensin II AT1 receptors. The current treatment paradigm for these diseases entails the preferred use of inverse agonist AT1 receptor blockers (ARBs). However, variability in the inverse agonist activities of common biphenyl-tetrazole ARBs for the active state of AT1 receptors often leads to treatment failure. Therefore, characterization of robust inverse agonist ARBs for the active state of AT1 receptors is necessary. EXPERIMENTAL APPROACH To identify the robust inverse agonist for active state of AT1 receptors and its molecular mechanism, we performed site-directed mutagenesis, competition binding assay, inositol phosphate production assay and molecular modelling for both ground-state wild-type AT1 receptors and active-state N111G mutant AT1 receptors. KEY RESULTS Although candesartan and telmisartan exhibited weaker inverse agonist activity for N111G- compared with WT-AT1 receptors, only eprosartan exhibited robust inverse agonist activity for both N111G- and WT- AT1 receptors. Specific ligand-receptor contacts for candesartan and telmisartan are altered in the active-state N111G- AT1 receptors compared with the ground-state WT-AT1 receptors, suggesting an explanation of their attenuated inverse agonist activity for the active state of AT1 receptors. In contrast, interactions between eprosartan and N111G-AT1 receptors were not significantly altered, and the inverse agonist activity of eprosartan was robust. CONCLUSIONS AND IMPLICATIONS Eprosartan may be a better therapeutic option than other ARBs. Comparative studies investigating eprosartan and other ARBs for the treatment of diseases caused by chronic, agonist-independent, AT1 receptor activation are warranted.
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Affiliation(s)
- Takanobu Takezako
- Department of Advanced Heart ResearchSaga UniversitySagaJapan
- Department of Internal MedicineNadeshiko Lady's HospitalKobeJapan
| | - Hamiyet Unal
- Department of Molecular Cardiology, Lerner Research InstituteCleveland Clinic FoundationClevelandOHUSA
| | - Sadashiva S Karnik
- Department of Molecular Cardiology, Lerner Research InstituteCleveland Clinic FoundationClevelandOHUSA
| | - Koichi Node
- Department of Cardiovascular MedicineSaga UniversitySagaJapan
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Durdagi S, Erol I, Salmas RE, Aksoydan B, Kantarcioglu I. Oligomerization and cooperativity in GPCRs from the perspective of the angiotensin AT1 and dopamine D2 receptors. Neurosci Lett 2018; 700:30-37. [PMID: 29684528 DOI: 10.1016/j.neulet.2018.04.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 04/13/2018] [Accepted: 04/16/2018] [Indexed: 12/22/2022]
Abstract
G Protein-Coupled Receptors (GPCRs) can form homo- and heterodimers or constitute higher oligomeric clusters with other heptahelical GPCRs. In this article, multiscale molecular modeling approaches as well as experimental techniques which are used to study oligomerization of GPCRs are reviewed. In particular, the effect of dimerization/oligomerization to the ligand binding affinity of individual protomers and also on the efficacy of the oligomer are discussed by including diverse examples from the literature. In addition, possible allosteric effects that may emerge upon interaction of GPCRs with membrane components, like cholesterol, is also discussed. Investigation of these above-mentioned interactions may greatly contribute to the candidate molecule screening studies and development of novel therapeutics with fewer adverse effects.
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Affiliation(s)
- Serdar Durdagi
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahcesehir University (BAU), Istanbul, Turkey; Neuroscience Program, Graduate School of Health Sciences, Bahcesehir University, Istanbul, Turkey.
| | - Ismail Erol
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahcesehir University (BAU), Istanbul, Turkey; Department of Chemistry, Gebze Technical University, Kocaeli, Turkey
| | - Ramin Ekhteiari Salmas
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahcesehir University (BAU), Istanbul, Turkey
| | - Busecan Aksoydan
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahcesehir University (BAU), Istanbul, Turkey; Neuroscience Program, Graduate School of Health Sciences, Bahcesehir University, Istanbul, Turkey
| | - Isik Kantarcioglu
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahcesehir University (BAU), Istanbul, Turkey; Bioengineering Program, Graduate School of Natural and Applied Sciences, Bahcesehir University, Istanbul, Turkey
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Takezako T, Unal H, Karnik SS, Node K. Current topics in angiotensin II type 1 receptor research: Focus on inverse agonism, receptor dimerization and biased agonism. Pharmacol Res 2017. [PMID: 28648738 DOI: 10.1016/j.phrs.2017.06.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Although the octapeptide hormone angiotensin II (Ang II) regulates cardiovascular and renal homeostasis through the Ang II type 1 receptor (AT1R), overstimulation of AT1R causes various human diseases, such as hypertension and cardiac hypertrophy. Therefore, AT1R blockers (ARBs) have been widely used as therapeutic drugs for these diseases. Recent basic research and clinical studies have resulted in the discovery of interesting phenomena associated with AT1R function. For example, ligand-independent activation of AT1R by mechanical stress and agonistic autoantibodies, as well as via receptor mutations, has been shown to decrease the inverse agonistic efficacy of ARBs, though the molecular mechanisms of such phenomena had remained elusive until recently. Furthermore, although AT1R is believed to exist as a monomer, recent studies have demonstrated that AT1R can homodimerize and heterodimerize with other G-protein coupled receptors (GPCR), altering the receptor signaling properties. Therefore, formation of both AT1R homodimers and AT1R-GPCR heterodimer may be involved in the pathogenesis of human disease states, such as atherosclerosis and preeclampsia. Finally, biased AT1R ligands that can preferentially activate the β-arrestin-mediated signaling pathway have been discovered. Such β-arrestin-biased AT1R ligands may be better therapeutic drugs for cardiovascular diseases. New findings on AT1R described herein could provide a conceptual framework for application of ARBs in the treatment of diseases, as well as for novel drug development. Since AT1R is an extensively studied member of the GPCR superfamily encoded in the human genome, this review is relevant for understanding the functions of other members of this superfamily.
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Affiliation(s)
- Takanobu Takezako
- Department of Advanced Heart Research, Saga University, Saga, Japan; Medical Center for Student Health, Kobe University, Kobe, Japan.
| | - Hamiyet Unal
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Sadashiva S Karnik
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Koichi Node
- Department of Cardiovascular Medicine, Saga University, Japan
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Shimizu Y, Ogawa K, Nakayama M. Characterization of Kinetic Binding Properties of Unlabeled Ligands via a Preincubation Endpoint Binding Approach. ACTA ACUST UNITED AC 2016; 21:729-37. [PMID: 27270099 DOI: 10.1177/1087057116652065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 05/06/2016] [Indexed: 11/16/2022]
Abstract
The dissociation rates of unlabeled drugs have been well studied by kinetic binding analyses. Since kinetic assays are laborious, we developed a simple method to determine the kinetic binding parameters of unlabeled competitors by a preincubation endpoint assay. The probe binding after preincubation of a competitor can be described by a single equation as a function of time. Simulations using the equation revealed the degree of IC50 change induced by preincubation of a competitor depended on the dissociation rate koff of the competitor but not on the association rate kon To validate the model, an in vitro binding assay was performed using a smoothened receptor (SMO) and [(3)H]TAK-441, a SMO antagonist. The equilibrium dissociation constants (KI) and koff of SMO antagonists determined by globally fitting the model to the concentration-response curves obtained with and without 24 h preincubation correlated well with those determined by other methods. This approach could be useful for early-stage optimization of drug candidates by enabling determination of binding kinetics in a high-throughput manner because it does not require kinetic measurements, an intermediate washout step during the reaction, or prior determination of competitors' KI values.
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Affiliation(s)
- Yuji Shimizu
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Kazumasa Ogawa
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Masaharu Nakayama
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
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Karnik SS, Unal H, Kemp JR, Tirupula KC, Eguchi S, Vanderheyden PML, Thomas WG. International Union of Basic and Clinical Pharmacology. XCIX. Angiotensin Receptors: Interpreters of Pathophysiological Angiotensinergic Stimuli [corrected]. Pharmacol Rev 2015; 67:754-819. [PMID: 26315714 PMCID: PMC4630565 DOI: 10.1124/pr.114.010454] [Citation(s) in RCA: 207] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The renin angiotensin system (RAS) produced hormone peptides regulate many vital body functions. Dysfunctional signaling by receptors for RAS peptides leads to pathologic states. Nearly half of humanity today would likely benefit from modern drugs targeting these receptors. The receptors for RAS peptides consist of three G-protein-coupled receptors—the angiotensin II type 1 receptor (AT1 receptor), the angiotensin II type 2 receptor (AT2 receptor), the MAS receptor—and a type II trans-membrane zinc protein—the candidate angiotensin IV receptor (AngIV binding site). The prorenin receptor is a relatively new contender for consideration, but is not included here because the role of prorenin receptor as an independent endocrine mediator is presently unclear. The full spectrum of biologic characteristics of these receptors is still evolving, but there is evidence establishing unique roles of each receptor in cardiovascular, hemodynamic, neurologic, renal, and endothelial functions, as well as in cell proliferation, survival, matrix-cell interaction, and inflammation. Therapeutic agents targeted to these receptors are either in active use in clinical intervention of major common diseases or under evaluation for repurposing in many other disorders. Broad-spectrum influence these receptors produce in complex pathophysiological context in our body highlights their role as precise interpreters of distinctive angiotensinergic peptide cues. This review article summarizes findings published in the last 15 years on the structure, pharmacology, signaling, physiology, and disease states related to angiotensin receptors. We also discuss the challenges the pharmacologist presently faces in formally accepting newer members as established angiotensin receptors and emphasize necessary future developments.
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Affiliation(s)
- Sadashiva S Karnik
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Hamiyet Unal
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Jacqueline R Kemp
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Kalyan C Tirupula
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Satoru Eguchi
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Patrick M L Vanderheyden
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Walter G Thomas
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
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Vauquelin G, Huber W, Swinney DC. Experimental Methods to Determine Binding Kinetics. THERMODYNAMICS AND KINETICS OF DRUG BINDING 2015. [DOI: 10.1002/9783527673025.ch9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Takezako T, Unal H, Karnik SS, Node K. Structure-Function Basis of Attenuated Inverse Agonism of Angiotensin II Type 1 Receptor Blockers for Active-State Angiotensin II Type 1 Receptor. Mol Pharmacol 2015; 88:488-501. [PMID: 26121982 DOI: 10.1124/mol.115.099176] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 06/29/2015] [Indexed: 01/05/2023] Open
Abstract
Ligand-independent signaling by the angiotensin II type 1 receptor (AT1R) can be activated in clinical settings by mechanical stretch and autoantibodies as well as receptor mutations. Transition of the AT1R to the activated state is known to lower inverse agonistic efficacy of clinically used AT1R blockers (ARBs). The structure-function basis for reduced efficacy of inverse agonists is a fundamental aspect that has been understudied not only in relation to the AT1R but also regarding other homologous receptors. Here, we demonstrate that the active-state transition in the AT1R indeed attenuates an inverse agonistic effect of four biphenyl-tetrazole ARBs through changes in specific ligand-receptor interactions. In the ground state, tight interactions of four ARBs with a set of residues (Ser109(TM3), Phe182(ECL2), Gln257(TM6), Tyr292(TM7), and Asn295(TM7)) results in potent inverse agonism. In the activated state, the ARB-AT1R interactions shift to a different set of residues (Val108(TM3), Ser109(TM3), Ala163(TM4), Phe182(ECL2), Lys199(TM5), Tyr292(TM7), and Asn295(TM7)), resulting in attenuated inverse agonism. Interestingly, V108I, A163T, N295A, and F182A mutations in the activated state of the AT1R shift the functional response to the ARB binding toward agonism, but in the ground state the same mutations cause inverse agonism. Our data show that the second extracellular loop is an important regulator of the functional states of the AT1R. Our findings suggest that the quest for discovering novel ARBs, and improving current ARBs, fundamentally depends on the knowledge of the unique sets of residues that mediate inverse agonistic potency in the two states of the AT1R.
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Affiliation(s)
- Takanobu Takezako
- Department of Advanced Heart Research, Saga University, Saga, Japan (T.T.); Department of Cardiovascular Medicine, Saga University, Saga, Japan (K.N.); Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio (H.U., S.S.K.); Department of Biosignal Pathophysiology, Kobe University Graduate School of Medicine, Kobe, Japan (T.T.); and Department of Basic Sciences, Faculty of Pharmacy and Betul Ziya Eren Genome and Stem Cell Center, Erciyes University, Kayseri, Turkey (H.U.)
| | - Hamiyet Unal
- Department of Advanced Heart Research, Saga University, Saga, Japan (T.T.); Department of Cardiovascular Medicine, Saga University, Saga, Japan (K.N.); Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio (H.U., S.S.K.); Department of Biosignal Pathophysiology, Kobe University Graduate School of Medicine, Kobe, Japan (T.T.); and Department of Basic Sciences, Faculty of Pharmacy and Betul Ziya Eren Genome and Stem Cell Center, Erciyes University, Kayseri, Turkey (H.U.)
| | - Sadashiva S Karnik
- Department of Advanced Heart Research, Saga University, Saga, Japan (T.T.); Department of Cardiovascular Medicine, Saga University, Saga, Japan (K.N.); Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio (H.U., S.S.K.); Department of Biosignal Pathophysiology, Kobe University Graduate School of Medicine, Kobe, Japan (T.T.); and Department of Basic Sciences, Faculty of Pharmacy and Betul Ziya Eren Genome and Stem Cell Center, Erciyes University, Kayseri, Turkey (H.U.)
| | - Koichi Node
- Department of Advanced Heart Research, Saga University, Saga, Japan (T.T.); Department of Cardiovascular Medicine, Saga University, Saga, Japan (K.N.); Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio (H.U., S.S.K.); Department of Biosignal Pathophysiology, Kobe University Graduate School of Medicine, Kobe, Japan (T.T.); and Department of Basic Sciences, Faculty of Pharmacy and Betul Ziya Eren Genome and Stem Cell Center, Erciyes University, Kayseri, Turkey (H.U.)
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Structure of the Angiotensin receptor revealed by serial femtosecond crystallography. Cell 2015; 161:833-44. [PMID: 25913193 DOI: 10.1016/j.cell.2015.04.011] [Citation(s) in RCA: 269] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 12/30/2014] [Accepted: 03/02/2015] [Indexed: 01/01/2023]
Abstract
Angiotensin II type 1 receptor (AT(1)R) is a G protein-coupled receptor that serves as a primary regulator for blood pressure maintenance. Although several anti-hypertensive drugs have been developed as AT(1)R blockers (ARBs), the structural basis for AT(1)R ligand-binding and regulation has remained elusive, mostly due to the difficulties of growing high-quality crystals for structure determination using synchrotron radiation. By applying the recently developed method of serial femtosecond crystallography at an X-ray free-electron laser, we successfully determined the room-temperature crystal structure of the human AT(1)R in complex with its selective antagonist ZD7155 at 2.9-Å resolution. The AT(1)R-ZD7155 complex structure revealed key structural features of AT(1)R and critical interactions for ZD7155 binding. Docking simulations of the clinically used ARBs into the AT(1)R structure further elucidated both the common and distinct binding modes for these anti-hypertensive drugs. Our results thereby provide fundamental insights into AT(1)R structure-function relationship and structure-based drug design.
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Swinney DC, Beavis P, Chuang KT, Zheng Y, Lee I, Gee P, Deval J, Rotstein DM, Dioszegi M, Ravendran P, Zhang J, Sankuratri S, Kondru R, Vauquelin G. A study of the molecular mechanism of binding kinetics and long residence times of human CCR5 receptor small molecule allosteric ligands. Br J Pharmacol 2015; 171:3364-75. [PMID: 24628038 DOI: 10.1111/bph.12683] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Revised: 02/04/2014] [Accepted: 02/26/2014] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND AND PURPOSE The human CCR5 receptor is a co-receptor for HIV-1 infection and a target for anti-viral therapy. A greater understanding of the binding kinetics of small molecule allosteric ligand interactions with CCR5 will lead to a better understanding of the binding process and may help discover new molecules that avoid resistance. EXPERIMENTAL APPROACH Using [(3) H] maraviroc as a radioligand, a number of different binding protocols were employed in conjunction with simulations to determine rate constants, kinetic mechanism and mutant kinetic fingerprints for wild-type and mutant human CCR5 with maraviroc, aplaviroc and vicriviroc. KEY RESULTS Kinetic characterization of maraviroc binding to the wild-type CCR5 was consistent with a two-step kinetic mechanism that involved an initial receptor-ligand complex (RA), which transitioned to a more stable complex, R'A, with at least a 13-fold increase in affinity. The dissociation rate from R'A, k-2 , was 1.2 × 10(-3) min(-1) . The maraviroc time-dependent transition was influenced by F85L, W86A, Y108A, I198A and Y251A mutations of CCR5. CONCLUSIONS AND IMPLICATIONS The interaction between maraviroc and CCR5 proceeded according to a multi-step kinetic mechanism, whereby initial mass action binding and later reorganizations of the initial maraviroc-receptor complex lead to a complex with longer residence time. Site-directed mutagenesis identified a kinetic fingerprint of residues that affected the binding kinetics, leading to the conclusion that allosteric ligand binding to CCR5 involved the rearrangement of the binding site in a manner specific to each allosteric ligand.
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Affiliation(s)
- David C Swinney
- Roche Palo Alto, Palo Alto, CA, USA; Institute for Rare and Neglected Diseases Drug Discovery, Mountain View, CA, USA
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Reassessment of the unique mode of binding between angiotensin II type 1 receptor and their blockers. PLoS One 2013; 8:e79914. [PMID: 24260317 PMCID: PMC3832659 DOI: 10.1371/journal.pone.0079914] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 09/25/2013] [Indexed: 11/30/2022] Open
Abstract
While the molecular structures of angiotensin II (Ang II) type 1 (AT1) receptor blockers (ARBs) are very similar, they are also slightly different. Although each ARB has been shown to exhibit a unique mode of binding to AT1 receptor, different positions of the AT1 receptor have been analyzed and computational modeling has been performed using different crystal structures for the receptor as a template and different kinds of software. Therefore, we systematically analyzed the critical positions of the AT1 receptor, Tyr113, Tyr184, Lys199, His256 and Gln257 using a mutagenesis study, and subsequently performed computational modeling of the binding of ARBs to AT1 receptor using CXCR4 receptor as a new template and a single version of software. The interactions between Tyr113 in the AT1 receptor and the hydroxyl group of olmesartan, between Lys199 and carboxyl or tetrazole groups, and between His256 or Gln257 and the tetrazole group were studied. The common structure, a tetrazole group, of most ARBs similarly bind to Lys199, His256 and Gln257 of AT1 receptor. Lys199 in the AT1 receptor binds to the carboxyl group of EXP3174, candesartan and azilsartan, whereas oxygen in the amidecarbonyl group of valsartan may bind to Lys199. The benzimidazole portion of telmisartan may bind to a lipophilic pocket that includes Tyr113. On the other hand, the n-butyl group of irbesartan may bind to Tyr113. In conclusion, we confirmed that the slightly different structures of ARBs may be critical for binding to AT1 receptor and for the formation of unique modes of binding.
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Matsoukas MT, Cordomí A, Ríos S, Pardo L, Tselios T. Ligand binding determinants for angiotensin II type 1 receptor from computer simulations. J Chem Inf Model 2013; 53:2874-83. [PMID: 24090110 DOI: 10.1021/ci400400m] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The ligand binding determinants for the angiotensin II type 1 receptor (AT1R), a G protein-coupled receptor (GPCR), have been characterized by means of computer simulations. As a first step, a pharmacophore model of various known AT1R ligands exhibiting a wide range of binding affinities was generated. Second, a structural model of AT1R was built making use of the growing set of crystal structures of GPCRs, which was further used for the docking of the AT1R ligands based on the devised pharmacophore model. Next, ligand-receptor-lipid bilayer systems were studied by means of molecular dynamics (MD) simulations. Overall, the present study has permitted, combining the pharmacophore model with binding free energy calculations obtained from the MD simulations, to propose the molecular mechanisms by which sartans interact with AT1R.
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Matsoukas MT, Potamitis C, Plotas P, Androutsou ME, Agelis G, Matsoukas J, Zoumpoulakis P. Insights into AT1 receptor activation through AngII binding studies. J Chem Inf Model 2013; 53:2798-811. [PMID: 24053563 DOI: 10.1021/ci4003014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This study investigates the binding of angiotensin II (AngII) to the angiotensin II type 1 receptor (AT1R), taking into consideration several known activation elements that have been observed for G-protein-coupled receptors (GPCRs). In order to determine the crucial interactions of AngII upon binding, several MD simulations were implemented using AngII conformations derived from experimental data (NMR ROEs) and in silico flexible docking methodologies. An additional goal was to simulate the induced activation mechanism and examine the already known structural rearrangements of GPCRs upon activation. Performing MD simulations to the AT1R - AngII - lipids complex, a series of dynamic changes in the topology of AngII and the intracellular part of the receptor were observed. Overall, the present study proposes a complete binding profile of AngII to the AT1R, as well as the key transitional elements of the receptor and the agonist peptide upon activation through NMR and in silico studies.
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Affiliation(s)
- Minos-Timotheos Matsoukas
- Laboratori de Medicina Computacional, Unitat de Bioestadıstica, Facultat de Medicina, Universitat Autonoma de Barcelona , E-08193, Bellaterra, Barcelona, Spain
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15
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Fillion D, Cabana J, Guillemette G, Leduc R, Lavigne P, Escher E. Structure of the human angiotensin II type 1 (AT1) receptor bound to angiotensin II from multiple chemoselective photoprobe contacts reveals a unique peptide binding mode. J Biol Chem 2013; 288:8187-8197. [PMID: 23386604 DOI: 10.1074/jbc.m112.442053] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Breakthroughs in G protein-coupled receptor structure determination based on crystallography have been mainly obtained from receptors occupied in their transmembrane domain core by low molecular weight ligands, and we have only recently begun to elucidate how the extracellular surface of G protein-coupled receptors (GPCRs) allows for the binding of larger peptide molecules. In the present study, we used a unique chemoselective photoaffinity labeling strategy, the methionine proximity assay, to directly identify at physiological conditions a total of 38 discrete ligand/receptor contact residues that form the extracellular peptide-binding site of an activated GPCR, the angiotensin II type 1 receptor. This experimental data set was used in homology modeling to guide the positioning of the angiotensin II (AngII) peptide within several GPCR crystal structure templates. We found that the CXC chemokine receptor type 4 accommodated the results better than the other templates evaluated; ligand/receptor contact residues were spatially grouped into defined interaction clusters with AngII. In the resulting receptor structure, a β-hairpin fold in extracellular loop 2 in conjunction with two extracellular disulfide bridges appeared to open and shape the entrance of the ligand-binding site. The bound AngII adopted a somewhat vertical binding mode, allowing concomitant contacts across the extracellular surface and deep within the transmembrane domain core of the receptor. We propose that such a dualistic nature of GPCR interaction could be well suited for diffusible linear peptide ligands and a common feature of other peptidergic class A GPCRs.
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Affiliation(s)
- Dany Fillion
- Department of Pharmacology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Jérôme Cabana
- Department of Pharmacology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Gaétan Guillemette
- Department of Pharmacology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Richard Leduc
- Department of Pharmacology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Pierre Lavigne
- Department of Pharmacology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Emanuel Escher
- Department of Pharmacology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada.
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16
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Arao T, Okada Y, Mori H, Nishida K, Tanaka Y. Antihypertensive and metabolic effects of high-dose olmesartan and telmisartan in type 2 diabetes patients with hypertension. Endocr J 2013; 60:563-70. [PMID: 23303198 DOI: 10.1507/endocrj.ej12-0326] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We performed a crossover study in hypertensive patients with type 2 diabetes to compare olmesartan (40 mg/day) with telmisartan (80 mg/day) in terms of their antihypertensive and metabolic effects. The subjects were 36 patients (20 men and 16 women) with type 2 diabetes who did not achieve a blood pressure <130/80 mmHg following treatment with olmesartan at 40 mg/day or telmisartan at 80 mg/day for 8 weeks or more. The primary endpoint was the blood pressure reduction rate, while the secondary endpoints were BMI, parameters of glucose metabolism, HMW-adiponectin, hs-CRP and lipids metabolism. All parameters were measured in Weeks 0, 12, and 24. Treatments were switched in Week 0, and Week 12 and the following results were obtained. There were 1) no significant differences in baseline characteristics; 2) no significant difference of the blood pressure reduction rate; 3) significant reductions of HbA1c (NGSP), FPG and HOMA-IR in olmesartan group; 4) a significant increase of HDL-C in olmesartan group; 5) a decrease of hs-CRP and a increase of HMW-adiponectin in olmesartan group; and 6) a positive correlation between the percent changes of HOMA-IR and hs-CRP in olmesartan group. In conclusion, there was no difference of the blood pressure reduction achieved at the highest dose in olmesartan group and telmisartan group. But improvement of glycemic control and insulin resistance was only observed in olmesartan group. Because there was a correlation between the percent changes of HOMA-IR and hs-CRP, these effects of olmesartan might be mediated by an anti-inflammatory action.
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Affiliation(s)
- Tadashi Arao
- The First Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan.
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17
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Miura SI, Okabe A, Matsuo Y, Karnik SS, Saku K. Unique binding behavior of the recently approved angiotensin II receptor blocker azilsartan compared with that of candesartan. Hypertens Res 2012; 36:134-9. [PMID: 23034464 DOI: 10.1038/hr.2012.147] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The angiotensin II type 1 (AT(1)) receptor blocker (ARB) candesartan strongly reduces blood pressure (BP) in patients with hypertension and has been shown to have cardioprotective effects. A new ARB, azilsartan, was recently approved and has been shown to provide a more potent 24-h sustained antihypertensive effect than candesartan. However, the molecular interactions of azilsartan with the AT(1) receptor that could explain its strong BP-lowering activity are not yet clear. To address this issue, we examined the binding affinities of ARBs for the AT(1) receptor and their inverse agonist activity toward the production of inositol phosphate (IP), and we constructed docking models for the interactions between ARBs and the receptor. Azilsartan, unlike candesartan, has a unique moiety, a 5-oxo-1,2,4-oxadiazole, in place of a tetrazole ring. Although the results regarding the binding affinities of azilsartan and candesartan demonstrated that these ARBs interact with the same sites in the AT(1) receptor (Tyr(113), Lys(199) and Gln(257)), the hydrogen bonding between the oxadiazole of azilsartan-Gln(257) is stronger than that between the tetrazole of candesartan-Gln(257), according to molecular docking models. An examination of the inhibition of IP production by ARBs using constitutively active mutant receptors indicated that inverse agonist activity required azilsartan-Gln(257) interaction and that azilsartan had a stronger interaction with Gln(257) than candesartan. Thus, we speculate that azilsartan has a unique binding behavior to the AT(1) receptor due to its 5-oxo-1,2,4-oxadiazole moiety and induces stronger inverse agonism. This property of azilsartan may underlie its previously demonstrated superior BP-lowering efficacy compared with candesartan and other ARBs.
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Affiliation(s)
- Shin-ichiro Miura
- Department of Cardiology, Fukuoka University School of Medicine, 7-45-1 Nanakuma, Jonan-ku, Fukuoka, Japan.
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18
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Moitra S, Tirupula KC, Klein-Seetharaman J, Langmead CJ. A minimal ligand binding pocket within a network of correlated mutations identified by multiple sequence and structural analysis of G protein coupled receptors. BMC BIOPHYSICS 2012; 5:13. [PMID: 22748306 PMCID: PMC3478154 DOI: 10.1186/2046-1682-5-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 06/21/2012] [Indexed: 01/07/2023]
Abstract
Background G protein coupled receptors (GPCRs) are seven helical transmembrane proteins that function as signal transducers. They bind ligands in their extracellular and transmembrane regions and activate cognate G proteins at their intracellular surface at the other side of the membrane. The relay of allosteric communication between the ligand binding site and the distant G protein binding site is poorly understood. In this study, GREMLIN
[1], a recently developed method that identifies networks of co-evolving residues from multiple sequence alignments, was used to identify those that may be involved in communicating the activation signal across the membrane. The GREMLIN-predicted long-range interactions between amino acids were analyzed with respect to the seven GPCR structures that have been crystallized at the time this study was undertaken. Results GREMLIN significantly enriches the edges containing residues that are part of the ligand binding pocket, when compared to a control distribution of edges drawn from a random graph. An analysis of these edges reveals a minimal GPCR binding pocket containing four residues (T1183.33, M2075.42, Y2686.51 and A2927.39). Additionally, of the ten residues predicted to have the most long-range interactions (A1173.32, A2726.55, E1133.28, H2115.46, S186EC2, A2927.39, E1223.37, G902.57, G1143.29 and M2075.42), nine are part of the ligand binding pocket. Conclusions We demonstrate the use of GREMLIN to reveal a network of statistically correlated and functionally important residues in class A GPCRs. GREMLIN identified that ligand binding pocket residues are extensively correlated with distal residues. An analysis of the GREMLIN edges across multiple structures suggests that there may be a minimal binding pocket common to the seven known GPCRs. Further, the activation of rhodopsin involves these long-range interactions between extracellular and intracellular domain residues mediated by the retinal domain.
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Affiliation(s)
- Subhodeep Moitra
- Computer Science Department, Carnegie Mellon University, Gates Hillman Center, 5000 Forbes Avenue, Pittsburgh, PA, USA
| | - Kalyan C Tirupula
- Department of Structural Biology, University of Pittsburgh School of Medicine, Rm. 2051, Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA, USA
| | - Judith Klein-Seetharaman
- Department of Structural Biology, University of Pittsburgh School of Medicine, Rm. 2051, Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA, USA
| | - Christopher James Langmead
- Computer Science Department, Carnegie Mellon University, Gates Hillman Center, 5000 Forbes Avenue, Pittsburgh, PA, USA
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19
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Kiya Y, Miura SI, Matsuo Y, Karnik SS, Saku K. Abilities of candesartan and other AT(1) receptor blockers to impair angiotensin II-induced AT(1) receptor activation after wash-out. J Renin Angiotensin Aldosterone Syst 2011; 13:76-83. [PMID: 21824992 DOI: 10.1177/1470320311417478] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Angiotensin II (Ang II) binds to Ang II type 1 (AT(1)) receptor and evokes cell signaling, and subsequently stimulates vasoconstriction and cell proliferation, which eventually lead to cardiovascular disease. Since most AT(1) receptor blockers (ARBs) have molecular (differential) effects, we evaluated the specific features of candesartan and compared the abilities of candesartan and other ARBs (olmesartan, telmisartan, valsartan, irbesartan and losartan) to bind to and activate AT(1) receptors using a cell-based wash-out assay. Each ARB blocked Ang II-induced extracellular signal-regulated kinase (ERK) activation and inositol phosphate production to different degrees after wash-out. In addition, a small difference in the molecular structure, i.e. a carboxyl group, between candesartan and candesartan-7H was associated with a difference in the degree of this blocking effect. In addition, interaction between Gln(257) in the AT(1) receptor and the carboxyl group of candesartan may be partially associated with the effect of candesartan after wash-out. Although our findings regarding the molecular effects of ARB are based on basic research, these findings may lead to an exciting new area in the clinical application of ARBs.
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Affiliation(s)
- Yoshihiro Kiya
- Department of Cardiology, Fukuoka University School of Medicine, Jonan-ku, Fukuoka, Japan
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20
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A small difference in the molecular structure of angiotensin II receptor blockers induces AT₁ receptor-dependent and -independent beneficial effects. Hypertens Res 2010; 33:1044-52. [PMID: 20668453 DOI: 10.1038/hr.2010.135] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Angiotensin II (Ang II) type 1 (AT₁) receptor blockers (ARBs) induce multiple pharmacological beneficial effects, but not all ARBs have the same effects and the molecular mechanisms underlying their actions are not certain. In this study, irbesartan and losartan were examined because of their different molecular structures (irbesartan has a cyclopentyl group whereas losartan has a chloride group). We analyzed the binding affinity and production of inositol phosphate (IP), monocyte chemoattractant protein-1 (MCP-1) and adiponectin. Compared with losartan, irbesartan showed a significantly higher binding affinity and slower dissociation rate from the AT₁ receptor and a significantly higher degree of inverse agonism and insurmountability toward IP production. These effects of irbesartan were not seen with the AT₁-Y113A mutant receptor. On the basis of the molecular modeling of the ARBs-AT₁ receptor complex and a mutagenesis study, the phenyl group at Tyr(113) in the AT₁ receptor and the cyclopentyl group of irbesartan may form a hydrophobic interaction that is stronger than the losartan-AT₁ receptor interaction. Interestingly, irbesartan inhibited MCP-1 production more strongly than losartan. This effect was mediated by the inhibition of nuclear factor-kappa B activation that was independent of the AT₁ receptor in the human coronary endothelial cells. In addition, irbesartan, but not losartan, induced significant adiponectin production that was mediated by peroxisome proliferator-activated receptor-γ activation in 3T3-L1 adipocytes, and this effect was not mediated by the AT₁ receptor. In conclusion, irbesartan induced greater beneficial effects than losartan due to small differences between their molecular structures, and these differential effects were both dependent on and independent of the AT₁ receptor.
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21
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Akazawa H, Yasuda N, Komuro I. Mechanisms and functions of agonist-independent activation in the angiotensin II type 1 receptor. Mol Cell Endocrinol 2009; 302:140-7. [PMID: 19059460 DOI: 10.1016/j.mce.2008.11.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 11/06/2008] [Accepted: 11/06/2008] [Indexed: 11/23/2022]
Abstract
The angiotensin II (AngII) type 1 (AT(1)) receptor is a seven-transmembrane G protein-coupled receptor, and is involved in regulating the physiological and pathological process of the cardiovascular system. Systemically and locally generated AngII has agonistic action on AT(1) receptor, but recent studies have demonstrated that AT(1) receptor inherently shows spontaneous activity even in the absence of AngII. Furthermore, mechanical stress can activate AT(1) receptor by inducing conformational switch without the involvement of AngII, and induce cardiac hypertrophy in vivo. These agonist-independent activities of AT(1) receptor can be inhibited by inverse agonists, but not by neutral antagonists. Considerable attention has been directed to molecular mechanisms and clinical implications of agonist-independent AT(1) receptor activation, and inverse agonist activity emerges as an important pharmacological parameter for AT(1) receptor blockers that will improve efficacy and expand therapeutic potentials in cardiovascular medicine.
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Affiliation(s)
- Hiroshi Akazawa
- Division of Cardiovascular Pathophysiology, Chiba University Graduate School of Medicine, Chuo-ku, Chiba, Japan
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22
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Huynh J, Thomas WG, Aguilar MI, Pattenden LK. Role of helix 8 in G protein-coupled receptors based on structure-function studies on the type 1 angiotensin receptor. Mol Cell Endocrinol 2009; 302:118-27. [PMID: 19418628 DOI: 10.1016/j.mce.2009.01.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
G protein-coupled receptors (GPCRs) are transmembrane receptors that convert extracellular stimuli to intracellular signals. The type 1 angiotensin II receptor is a widely studied GPCR with roles in blood pressure regulation,water and salt balance and cell growth. The complex molecular and structural changes that underpin receptor activation and signaling are the focus of intense research. Increasingly, there is an appreciation that the plasma membrane participates in receptor function via direct, physical interactions that reciprocally modulate both lipid and receptor and provide microdomains for specialized activities. Reversible protein:lipid interactions are commonly mediated by amphipathic -helices in proteins and one such motif - a short helix, referred to as helix VIII/8 (H8), located at the start of the carboxyl (C)-terminus of GPCRs - is gaining recognition for its importance to GPCR function. Here, we review the identification of H8 in GPCRs and examine its capacity to sense and interact with diverse proteins and lipid environment, most notably with acidic lipids that include phosphatidylinositol phosphates.
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MESH Headings
- Binding Sites
- Humans
- Lipids/chemistry
- Protein Binding
- Protein Structure, Secondary
- Receptor, Angiotensin, Type 1/chemistry
- Receptor, Angiotensin, Type 1/metabolism
- Receptor, Angiotensin, Type 1/physiology
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/metabolism
- Receptors, G-Protein-Coupled/physiology
- Signal Transduction
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Affiliation(s)
- John Huynh
- School of Biomedical Sciences, The University of Queensland, Brisbane, St Lucia, Queensland, Australia
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23
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Potamitis C, Zervou M, Katsiaras V, Zoumpoulakis P, Durdagi S, Papadopoulos MG, Hayes JM, Grdadolnik SG, Kyrikou I, Argyropoulos D, Vatougia G, Mavromoustakos T. Antihypertensive Drug Valsartan in Solution and at the AT1 Receptor: Conformational Analysis, Dynamic NMR Spectroscopy, in Silico Docking, and Molecular Dynamics Simulations. J Chem Inf Model 2009; 49:726-39. [DOI: 10.1021/ci800427s] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Constantinos Potamitis
- National Hellenic Research Foundation, Institute of Organic and Pharmaceutical Chemistry, Vas, Constantinou 48, 11635, Athens, Greece, Department of Biology Chemistry and Pharmacy, Free University of Berlin, Takustrasse, 3, 14195 Berlin, Germany, Laboratory of Biomolecular Structure, National Institute of Chemistry, Hajdrihova 19, POB 30 SI-1115 Ljubljana, Slovenia, Varian Ltd., 10 Mead Road, Oxford Industrial Park, Yarnton, Oxford OX5 1QU, United Kingdom, Chemistry Department, National & Kapodistrian
| | - Maria Zervou
- National Hellenic Research Foundation, Institute of Organic and Pharmaceutical Chemistry, Vas, Constantinou 48, 11635, Athens, Greece, Department of Biology Chemistry and Pharmacy, Free University of Berlin, Takustrasse, 3, 14195 Berlin, Germany, Laboratory of Biomolecular Structure, National Institute of Chemistry, Hajdrihova 19, POB 30 SI-1115 Ljubljana, Slovenia, Varian Ltd., 10 Mead Road, Oxford Industrial Park, Yarnton, Oxford OX5 1QU, United Kingdom, Chemistry Department, National & Kapodistrian
| | - Vassilis Katsiaras
- National Hellenic Research Foundation, Institute of Organic and Pharmaceutical Chemistry, Vas, Constantinou 48, 11635, Athens, Greece, Department of Biology Chemistry and Pharmacy, Free University of Berlin, Takustrasse, 3, 14195 Berlin, Germany, Laboratory of Biomolecular Structure, National Institute of Chemistry, Hajdrihova 19, POB 30 SI-1115 Ljubljana, Slovenia, Varian Ltd., 10 Mead Road, Oxford Industrial Park, Yarnton, Oxford OX5 1QU, United Kingdom, Chemistry Department, National & Kapodistrian
| | - Panagiotis Zoumpoulakis
- National Hellenic Research Foundation, Institute of Organic and Pharmaceutical Chemistry, Vas, Constantinou 48, 11635, Athens, Greece, Department of Biology Chemistry and Pharmacy, Free University of Berlin, Takustrasse, 3, 14195 Berlin, Germany, Laboratory of Biomolecular Structure, National Institute of Chemistry, Hajdrihova 19, POB 30 SI-1115 Ljubljana, Slovenia, Varian Ltd., 10 Mead Road, Oxford Industrial Park, Yarnton, Oxford OX5 1QU, United Kingdom, Chemistry Department, National & Kapodistrian
| | - Serdar Durdagi
- National Hellenic Research Foundation, Institute of Organic and Pharmaceutical Chemistry, Vas, Constantinou 48, 11635, Athens, Greece, Department of Biology Chemistry and Pharmacy, Free University of Berlin, Takustrasse, 3, 14195 Berlin, Germany, Laboratory of Biomolecular Structure, National Institute of Chemistry, Hajdrihova 19, POB 30 SI-1115 Ljubljana, Slovenia, Varian Ltd., 10 Mead Road, Oxford Industrial Park, Yarnton, Oxford OX5 1QU, United Kingdom, Chemistry Department, National & Kapodistrian
| | - Manthos G. Papadopoulos
- National Hellenic Research Foundation, Institute of Organic and Pharmaceutical Chemistry, Vas, Constantinou 48, 11635, Athens, Greece, Department of Biology Chemistry and Pharmacy, Free University of Berlin, Takustrasse, 3, 14195 Berlin, Germany, Laboratory of Biomolecular Structure, National Institute of Chemistry, Hajdrihova 19, POB 30 SI-1115 Ljubljana, Slovenia, Varian Ltd., 10 Mead Road, Oxford Industrial Park, Yarnton, Oxford OX5 1QU, United Kingdom, Chemistry Department, National & Kapodistrian
| | - Joseph M. Hayes
- National Hellenic Research Foundation, Institute of Organic and Pharmaceutical Chemistry, Vas, Constantinou 48, 11635, Athens, Greece, Department of Biology Chemistry and Pharmacy, Free University of Berlin, Takustrasse, 3, 14195 Berlin, Germany, Laboratory of Biomolecular Structure, National Institute of Chemistry, Hajdrihova 19, POB 30 SI-1115 Ljubljana, Slovenia, Varian Ltd., 10 Mead Road, Oxford Industrial Park, Yarnton, Oxford OX5 1QU, United Kingdom, Chemistry Department, National & Kapodistrian
| | - Simona Golic Grdadolnik
- National Hellenic Research Foundation, Institute of Organic and Pharmaceutical Chemistry, Vas, Constantinou 48, 11635, Athens, Greece, Department of Biology Chemistry and Pharmacy, Free University of Berlin, Takustrasse, 3, 14195 Berlin, Germany, Laboratory of Biomolecular Structure, National Institute of Chemistry, Hajdrihova 19, POB 30 SI-1115 Ljubljana, Slovenia, Varian Ltd., 10 Mead Road, Oxford Industrial Park, Yarnton, Oxford OX5 1QU, United Kingdom, Chemistry Department, National & Kapodistrian
| | - Ioanna Kyrikou
- National Hellenic Research Foundation, Institute of Organic and Pharmaceutical Chemistry, Vas, Constantinou 48, 11635, Athens, Greece, Department of Biology Chemistry and Pharmacy, Free University of Berlin, Takustrasse, 3, 14195 Berlin, Germany, Laboratory of Biomolecular Structure, National Institute of Chemistry, Hajdrihova 19, POB 30 SI-1115 Ljubljana, Slovenia, Varian Ltd., 10 Mead Road, Oxford Industrial Park, Yarnton, Oxford OX5 1QU, United Kingdom, Chemistry Department, National & Kapodistrian
| | - Dimitris Argyropoulos
- National Hellenic Research Foundation, Institute of Organic and Pharmaceutical Chemistry, Vas, Constantinou 48, 11635, Athens, Greece, Department of Biology Chemistry and Pharmacy, Free University of Berlin, Takustrasse, 3, 14195 Berlin, Germany, Laboratory of Biomolecular Structure, National Institute of Chemistry, Hajdrihova 19, POB 30 SI-1115 Ljubljana, Slovenia, Varian Ltd., 10 Mead Road, Oxford Industrial Park, Yarnton, Oxford OX5 1QU, United Kingdom, Chemistry Department, National & Kapodistrian
| | - Georgia Vatougia
- National Hellenic Research Foundation, Institute of Organic and Pharmaceutical Chemistry, Vas, Constantinou 48, 11635, Athens, Greece, Department of Biology Chemistry and Pharmacy, Free University of Berlin, Takustrasse, 3, 14195 Berlin, Germany, Laboratory of Biomolecular Structure, National Institute of Chemistry, Hajdrihova 19, POB 30 SI-1115 Ljubljana, Slovenia, Varian Ltd., 10 Mead Road, Oxford Industrial Park, Yarnton, Oxford OX5 1QU, United Kingdom, Chemistry Department, National & Kapodistrian
| | - Thomas Mavromoustakos
- National Hellenic Research Foundation, Institute of Organic and Pharmaceutical Chemistry, Vas, Constantinou 48, 11635, Athens, Greece, Department of Biology Chemistry and Pharmacy, Free University of Berlin, Takustrasse, 3, 14195 Berlin, Germany, Laboratory of Biomolecular Structure, National Institute of Chemistry, Hajdrihova 19, POB 30 SI-1115 Ljubljana, Slovenia, Varian Ltd., 10 Mead Road, Oxford Industrial Park, Yarnton, Oxford OX5 1QU, United Kingdom, Chemistry Department, National & Kapodistrian
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24
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Generation of an agonistic binding site for blockers of the M(3) muscarinic acetylcholine receptor. Biochem J 2008; 412:103-12. [PMID: 18237275 DOI: 10.1042/bj20071366] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
GPCRs (G-protein-coupled receptors) exist in a spontaneous equilibrium between active and inactive conformations that are stabilized by agonists and inverse agonists respectively. Because ligand binding of agonists and inverse agonists often occurs in a competitive manner, one can assume an overlap between both binding sites. Only a few studies report mutations in GPCRs that convert receptor blockers into agonists by unknown mechanisms. Taking advantage of a genetically modified yeast strain, we screened libraries of mutant M(3)Rs {M(3) mAChRs [muscarinic ACh (acetylcholine) receptors)]} and identified 13 mutants which could be activated by atropine (EC50 0.3-10 microM), an inverse agonist on wild-type M(3)R. Many of the mutations sensitizing M(3)R to atropine activation were located at the junction of intracellular loop 3 and helix 6, a region known to be involved in G-protein coupling. In addition to atropine, the pharmacological switch was found for other M(3)R blockers such as scopolamine, pirenzepine and oxybutynine. However, atropine functions as an agonist on the mutant M(3)R only when expressed in yeast, but not in mammalian COS-7 cells, although high-affinity ligand binding was comparable in both expression systems. Interestingly, we found that atropine still blocks carbachol-induced activation of the M(3)R mutants in the yeast expression system by binding at the high-affinity-binding site (Ki approximately 10 nM). Our results indicate that blocker-to-agonist converting mutations enable atropine to function as both agonist and antagonist by interaction with two functionally distinct binding sites.
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25
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Betz SF, Zhu YF, Chen C, Struthers RS. Non-Peptide Gonadotropin-Releasing Hormone Receptor Antagonists. J Med Chem 2008; 51:3331-48. [DOI: 10.1021/jm701249f] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Stephen F. Betz
- Endocrinology & Metabolism, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Yun-Fei Zhu
- Endocrinology & Metabolism, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Chen Chen
- Endocrinology & Metabolism, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - R. Scott Struthers
- Endocrinology & Metabolism, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
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26
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Cappelli A, Nannicini C, Gallelli A, Giuliani G, Valenti S, Mohr GP, Anzini M, Mennuni L, Ferrari F, Caselli G, Giordani A, Peris W, Makovec F, Giorgi G, Vomero S. Design, Synthesis, and Biological Evaluation of AT1 Angiotensin II Receptor Antagonists Based on the Pyrazolo[3,4-b]pyridine and Related Heteroaromatic Bicyclic Systems. J Med Chem 2008; 51:2137-46. [DOI: 10.1021/jm7011563] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Andrea Cappelli
- Dipartimento Farmaco Chimico Tecnologico and European Research Centre for Drug Discovery and Development, Università di Siena, Via A. Moro, 53100 Siena, Italy, Rottapharm S.p.A., Via Valosa di Sopra 7, 20052 Monza, Italy, and Dipartimento di Chimica, Università di Siena, Via A. Moro, 53100 Siena, Italy
| | - Chiara Nannicini
- Dipartimento Farmaco Chimico Tecnologico and European Research Centre for Drug Discovery and Development, Università di Siena, Via A. Moro, 53100 Siena, Italy, Rottapharm S.p.A., Via Valosa di Sopra 7, 20052 Monza, Italy, and Dipartimento di Chimica, Università di Siena, Via A. Moro, 53100 Siena, Italy
| | - Andrea Gallelli
- Dipartimento Farmaco Chimico Tecnologico and European Research Centre for Drug Discovery and Development, Università di Siena, Via A. Moro, 53100 Siena, Italy, Rottapharm S.p.A., Via Valosa di Sopra 7, 20052 Monza, Italy, and Dipartimento di Chimica, Università di Siena, Via A. Moro, 53100 Siena, Italy
| | - Germano Giuliani
- Dipartimento Farmaco Chimico Tecnologico and European Research Centre for Drug Discovery and Development, Università di Siena, Via A. Moro, 53100 Siena, Italy, Rottapharm S.p.A., Via Valosa di Sopra 7, 20052 Monza, Italy, and Dipartimento di Chimica, Università di Siena, Via A. Moro, 53100 Siena, Italy
| | - Salvatore Valenti
- Dipartimento Farmaco Chimico Tecnologico and European Research Centre for Drug Discovery and Development, Università di Siena, Via A. Moro, 53100 Siena, Italy, Rottapharm S.p.A., Via Valosa di Sopra 7, 20052 Monza, Italy, and Dipartimento di Chimica, Università di Siena, Via A. Moro, 53100 Siena, Italy
| | - Gal.la Pericot Mohr
- Dipartimento Farmaco Chimico Tecnologico and European Research Centre for Drug Discovery and Development, Università di Siena, Via A. Moro, 53100 Siena, Italy, Rottapharm S.p.A., Via Valosa di Sopra 7, 20052 Monza, Italy, and Dipartimento di Chimica, Università di Siena, Via A. Moro, 53100 Siena, Italy
| | - Maurizio Anzini
- Dipartimento Farmaco Chimico Tecnologico and European Research Centre for Drug Discovery and Development, Università di Siena, Via A. Moro, 53100 Siena, Italy, Rottapharm S.p.A., Via Valosa di Sopra 7, 20052 Monza, Italy, and Dipartimento di Chimica, Università di Siena, Via A. Moro, 53100 Siena, Italy
| | - Laura Mennuni
- Dipartimento Farmaco Chimico Tecnologico and European Research Centre for Drug Discovery and Development, Università di Siena, Via A. Moro, 53100 Siena, Italy, Rottapharm S.p.A., Via Valosa di Sopra 7, 20052 Monza, Italy, and Dipartimento di Chimica, Università di Siena, Via A. Moro, 53100 Siena, Italy
| | - Flora Ferrari
- Dipartimento Farmaco Chimico Tecnologico and European Research Centre for Drug Discovery and Development, Università di Siena, Via A. Moro, 53100 Siena, Italy, Rottapharm S.p.A., Via Valosa di Sopra 7, 20052 Monza, Italy, and Dipartimento di Chimica, Università di Siena, Via A. Moro, 53100 Siena, Italy
| | - Gianfranco Caselli
- Dipartimento Farmaco Chimico Tecnologico and European Research Centre for Drug Discovery and Development, Università di Siena, Via A. Moro, 53100 Siena, Italy, Rottapharm S.p.A., Via Valosa di Sopra 7, 20052 Monza, Italy, and Dipartimento di Chimica, Università di Siena, Via A. Moro, 53100 Siena, Italy
| | - Antonio Giordani
- Dipartimento Farmaco Chimico Tecnologico and European Research Centre for Drug Discovery and Development, Università di Siena, Via A. Moro, 53100 Siena, Italy, Rottapharm S.p.A., Via Valosa di Sopra 7, 20052 Monza, Italy, and Dipartimento di Chimica, Università di Siena, Via A. Moro, 53100 Siena, Italy
| | - Walter Peris
- Dipartimento Farmaco Chimico Tecnologico and European Research Centre for Drug Discovery and Development, Università di Siena, Via A. Moro, 53100 Siena, Italy, Rottapharm S.p.A., Via Valosa di Sopra 7, 20052 Monza, Italy, and Dipartimento di Chimica, Università di Siena, Via A. Moro, 53100 Siena, Italy
| | - Francesco Makovec
- Dipartimento Farmaco Chimico Tecnologico and European Research Centre for Drug Discovery and Development, Università di Siena, Via A. Moro, 53100 Siena, Italy, Rottapharm S.p.A., Via Valosa di Sopra 7, 20052 Monza, Italy, and Dipartimento di Chimica, Università di Siena, Via A. Moro, 53100 Siena, Italy
| | - Gianluca Giorgi
- Dipartimento Farmaco Chimico Tecnologico and European Research Centre for Drug Discovery and Development, Università di Siena, Via A. Moro, 53100 Siena, Italy, Rottapharm S.p.A., Via Valosa di Sopra 7, 20052 Monza, Italy, and Dipartimento di Chimica, Università di Siena, Via A. Moro, 53100 Siena, Italy
| | - Salvatore Vomero
- Dipartimento Farmaco Chimico Tecnologico and European Research Centre for Drug Discovery and Development, Università di Siena, Via A. Moro, 53100 Siena, Italy, Rottapharm S.p.A., Via Valosa di Sopra 7, 20052 Monza, Italy, and Dipartimento di Chimica, Università di Siena, Via A. Moro, 53100 Siena, Italy
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27
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Conformational switch of angiotensin II type 1 receptor underlying mechanical stress-induced activation. EMBO Rep 2008; 9:179-86. [PMID: 18202720 DOI: 10.1038/sj.embor.7401157] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 11/27/2007] [Accepted: 11/28/2007] [Indexed: 12/19/2022] Open
Abstract
The angiotensin II type 1 (AT(1)) receptor is a G protein-coupled receptor that has a crucial role in the development of load-induced cardiac hypertrophy. Here, we show that cell stretch leads to activation of the AT(1) receptor, which undergoes an anticlockwise rotation and a shift of transmembrane (TM) 7 into the ligand-binding pocket. As an inverse agonist, candesartan suppressed the stretch-induced helical movement of TM7 through the bindings of the carboxyl group of candesartan to the specific residues of the receptor. A molecular model proposes that the tight binding of candesartan to the AT(1) receptor stabilizes the receptor in the inactive conformation, preventing its shift to the active conformation. Our results show that the AT(1) receptor undergoes a conformational switch that couples mechanical stress-induced activation and inverse agonist-induced inactivation.
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28
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Miura SI, Kiya Y, Kanazawa T, Imaizumi S, Fujino M, Matsuo Y, Karnik SS, Saku K. Differential bonding interactions of inverse agonists of angiotensin II type 1 receptor in stabilizing the inactive state. Mol Endocrinol 2008; 22:139-46. [PMID: 17901125 PMCID: PMC2725753 DOI: 10.1210/me.2007-0312] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Accepted: 09/20/2007] [Indexed: 01/06/2023] Open
Abstract
Although the sartan family of angiotensin II type 1 (AT(1)) receptor blockers (ARBs), which includes valsartan, olmesartan, and losartan, have a common pharmacophore structure, their effectiveness in therapy differs. Although their efficacy may be related to their binding strength, this notion has changed with a better understanding of the molecular mechanism. Therefore, we hypothesized that each ARB differs with regard to its molecular interactions with AT(1) receptor in inducing inverse agonism. Interactions between valsartan and residues Ser(105), Ser(109), and Lys(199) were important for binding. Valsartan is a strong inverse agonist of constitutive inositol phosphate production by the wild-type and N111G mutant receptors. Substituted cysteine accessibility mapping studies indicated that valsartan, but not losartan, which has only weak inverse agonism, may stabilize the N111G receptor in an inactive state upon binding. In addition, the inverse agonism by valsatan was mostly abolished with S105A/S109A/K199Q substitutions in the N111G background. Molecular modeling suggested that Ser(109) and Lys(199) bind to phenyl and tetrazole groups of valsartan, respectively. Ser(105) is a candidate for binding to the carboxyl group of valsartan. Thus, the most critical interaction for inducing inverse agonism involves transmembrane (TM) V (Lys(199)) of AT(1) receptor although its inverse agonist potency is comparable to olmesartan, which bonds with TM III (Tyr(113)) and TM VI (His(256)). These results provide new insights into improving ARBs and development of new G protein-coupled receptor antagonists.
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Affiliation(s)
- Shin-ichiro Miura
- Department of Cardiology, Fukuoka University School of Medicine, Jonan-Ku, Fukuoka 814-0180, Japan.
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29
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Kohout TA, Xie Q, Reijmers S, Finn KJ, Guo Z, Zhu YF, Struthers RS. Trapping of a Nonpeptide Ligand by the Extracellular Domains of the Gonadotropin-Releasing Hormone Receptor Results in Insurmountable Antagonism. Mol Pharmacol 2007; 72:238-47. [PMID: 17409285 DOI: 10.1124/mol.107.035535] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Drugs that exhibit insurmountable antagonism are proposed to provide improved clinical efficacy through extended receptor blockade. Long-term suppression of the gonadotropin-releasing hormone receptor (GnRHR) is an important therapeutic approach for a number of sex hormone-dependent diseases. In this study, we describe the mechanism and structural components required for insurmountable activity of a GnRHR antagonist. TAK-013 behaves as an insurmountable antagonist at the human receptor (hGnRHR) but as a surmountable antagonist at the macaque receptor (mGnRHR). Mutation of the eight residues that differ between hGnRHR and mGnRHR identified Ser-203 and Leu-300 in extracellular loops (ECL) 2 and 3 of hGnRHR as essential for the insurmountability of TAK-013. Substitution of the corresponding residues in mGnRHR with Ser and Leu (mGnRHR-P203S/V300L) converts TAK-013 to an insurmountable antagonist. In addition, mutation of Met-24 to Leu in the amino terminus of hGnRHR also ablates the insurmountable antagonism of TAK-013. The mechanism of insurmountability of TAK-013 was determined to be governed by its rate of dissociation from the receptor. Although the association rates of TAK-013 to hGnRHR, mGnRHR, and mGnRHR-P203S/V300L do not differ, the dissociation rate half-life correlates closely with the degree of insurmountability observed (169, 9, and 55 min, respectively). Taken together, these data suggest a model of the GnRHR in which ECL2, ECL3, and the amino terminus engage with TAK-013 upon its binding to the transmembrane region of the receptor. These additional interactions form a "trap door" above TAK-013, restricting its dissociation and thus resulting in its insurmountability.
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Affiliation(s)
- Trudy A Kohout
- Department of Endocrinology, Neurocrine Biosciences Inc., 12790 El Camino Real, San Diego, CA 92130, USA.
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30
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Oliveira L, Costa-Neto CM, Nakaie CR, Schreier S, Shimuta SI, Paiva ACM. The Angiotensin II AT1 Receptor Structure-Activity Correlations in the Light of Rhodopsin Structure. Physiol Rev 2007; 87:565-92. [PMID: 17429042 DOI: 10.1152/physrev.00040.2005] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The most prevalent physiological effects of ANG II, the main product of the renin-angiotensin system, are mediated by the AT1 receptor, a rhodopsin-like AGPCR. Numerous studies of the cardiovascular effects of synthetic peptide analogs allowed a detailed mapping of ANG II's structural requirements for receptor binding and activation, which were complemented by site-directed mutagenesis studies on the AT1 receptor to investigate the role of its structure in ligand binding, signal transduction, phosphorylation, binding to arrestins, internalization, desensitization, tachyphylaxis, and other properties. The knowledge of the high-resolution structure of rhodopsin allowed homology modeling of the AT1 receptor. The models thus built and mutagenesis data indicate that physiological (agonist binding) or constitutive (mutated receptor) activation may involve different degrees of expansion of the receptor's central cavity. Residues in ANG II structure seem to control these conformational changes and to dictate the type of cytosolic event elicited during the activation. 1) Agonist aromatic residues (Phe8 and Tyr4) favor the coupling to G protein, and 2) absence of these residues can favor a mechanism leading directly to receptor internalization via phosphorylation by specific kinases of the receptor's COOH-terminal Ser and Thr residues, arrestin binding, and clathrin-dependent coated-pit vesicles. On the other hand, the NH2-terminal residues of the agonists ANG II and [Sar1]-ANG II were found to bind by two distinct modes to the AT1 receptor extracellular site flanked by the COOH-terminal segments of the EC-3 loop and the NH2-terminal domain. Since the [Sar1]-ligand is the most potent molecule to trigger tachyphylaxis in AT1 receptors, it was suggested that its corresponding binding mode might be associated with this special condition of receptors.
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Affiliation(s)
- Laerte Oliveira
- Department of Biophysics, Escola Paulista de Medicina, Federal University of São Paulo, Brazil.
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31
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Smit MJ, Vischer HF, Bakker RA, Jongejan A, Timmerman H, Pardo L, Leurs R. Pharmacogenomic and Structural Analysis of Constitutive G Protein–Coupled Receptor Activity. Annu Rev Pharmacol Toxicol 2007; 47:53-87. [PMID: 17029567 DOI: 10.1146/annurev.pharmtox.47.120505.105126] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
G protein-coupled receptors (GPCRs) respond to a chemically diverse plethora of signal transduction molecules. The notion that GPCRs also signal without an external chemical trigger, i.e., in a constitutive or spontaneous manner, resulted in a paradigm shift in the field of GPCR pharmacology. The discovery of constitutive GPCR activity and the fact that GPCR binding and signaling can be strongly affected by a single point mutation drew attention to the evolving area of GPCR pharmacogenomics. For a variety of GPCRs, point mutations have been convincingly linked to human disease. Mutations within conserved motifs, known to be involved in GPCR activation, might explain the properties of some naturally occurring, constitutively active GPCR variants linked to disease. In this review, we provide a brief historical introduction to the concept of constitutive receptor activity and the pharmacogenomic and structural aspects of constitutive receptor activity.
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Affiliation(s)
- Martine J Smit
- Leiden/Amsterdam Center for Drug Research, Division of Medicinal Chemistry, Vrije Universiteit, Faculty of Sciences, Department of Chemistry, 1081 HV Amsterdam, The Netherlands.
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32
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Patny A, Desai PV, Avery MA. Ligand-supported homology modeling of the human angiotensin II type 1 (AT1) receptor: Insights into the molecular determinants of telmisartan binding. Proteins 2006; 65:824-42. [PMID: 17034041 DOI: 10.1002/prot.21196] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Angiotensin II type 1 (AT(1)) receptor belongs to the super-family of G-protein-coupled receptors, and antagonists of the AT(1) receptor are effectively used in the treatment of hypertension. To understand the molecular interactions of these antagonists, such as losartan and telmisartan, with the AT(1) receptor, a homology model of the human AT(1) (hAT(1)) receptor with all connecting loops was constructed from the 2.6 A resolution crystal structure (PDB i.d., 1L9H) of bovine rhodopsin. The initial model generated by MODELLER was subjected to a stepwise ligand-supported model refinement. This protocol involved initial docking of non-peptide AT(1) antagonists in the putative binding site, followed by several rounds of iterative energy minimizations and molecular dynamics simulations. The final model was validated based on its correlation with several structure-activity relationships and site-directed mutagenesis data. The final model was also found to be in agreement with a previously reported AT(1) antagonist pharmacophore model. Docking studies were performed for a series of non-peptide AT(1) receptor antagonists in the active site of the final hAT(1) receptor model. The docking was able to identify key molecular interactions for all the AT(1) antagonists studied. Reasonable correlation was observed between the interaction energy values and the corresponding binding affinities of these ligands, providing further validation for the model. In addition, an extensive unrestrained molecular dynamics simulation showed that the docking-derived bound pose of telmisartan is energetically stable. Knowledge gained from the present studies can be used in structure-based drug design for developing novel ligands for the AT(1) receptor.
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Affiliation(s)
- Akshay Patny
- Department of Medicinal Chemistry, School of Pharmacy, University of Mississippi, Mississippi 38677-1848, USA
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33
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Sullivan SK, Hoare SRJ, Fleck BA, Zhu YF, Heise CE, Struthers RS, Crowe PD. Kinetics of nonpeptide antagonist binding to the human gonadotropin-releasing hormone receptor: Implications for structure–activity relationships and insurmountable antagonism. Biochem Pharmacol 2006; 72:838-49. [PMID: 16930559 DOI: 10.1016/j.bcp.2006.07.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Revised: 06/28/2006] [Accepted: 07/17/2006] [Indexed: 11/21/2022]
Abstract
Numerous nonpeptide ligands have been developed for the human gonadotropin-releasing hormone (GnRH) receptor as potential agents for treatment of disorders of the reproductive-endocrine axis. While the equilibrium binding of these ligands has been studied in detail, little is known of the kinetics of their receptor interaction. In this study we evaluated the kinetic structure-activity relationships (SAR) of uracil-series antagonists by measuring their association and dissociation rate constants. These constants were measured directly using a novel radioligand, [3H] NBI 42902, and indirectly for unlabeled ligands. Receptor association and dissociation of [3H] NBI 42902 was monophasic, with an association rate constant of 93+/-10 microM(-1) min(-1) and a dissociation rate constant of 0.16+/-0.02 h(-1) (t(1/2) of 4.3 h). Four unlabeled compounds were tested with varying substituents at the 2-position of the benzyl group at position 1 of the uracil (-F, -SO(CH3), -SO2(CH3) and -CF3). The nature of the substituent did not appreciably affect the association rate constant but varied the dissociation rate constant >50-fold (t(1/2) ranging from 52 min for -SO(CH3) to >43 h for -CF3). This SAR was poorly resolved in standard competition assays due to lack of equilibration. The functional consequences of the varying dissociation rate were investigated by measuring antagonism of GnRH-stimulated [3H] inositol phosphates accumulation. Slowly dissociating ligands displayed insurmountable antagonism (decrease of the GnRH E(max)) while antagonism by more rapidly dissociating ligands was surmountable (without effect on the GnRH E(max)). Therefore, evaluating the receptor binding kinetics of nonpeptide antagonists revealed SAR, not evident in standard competition assays, that defined at least in part the mode of functional antagonism by the ligands. These findings are of importance for the future definition of nonpeptide ligand SAR and for the identification of potentially useful slowly dissociating antagonists for the GnRH receptor.
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Affiliation(s)
- Susan K Sullivan
- Department of Pharmacology and Lead Discovery, Neurocrine Biosciences Inc., 12790 El Camino Real, San Diego, CA 92130, USA
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34
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Tuccinardi T, Calderone V, Rapposelli S, Martinelli A. Proposal of a New Binding Orientation for Non-Peptide AT1 Antagonists: Homology Modeling, Docking and Three-Dimensional Quantitative Structure−Activity Relationship Analysis. J Med Chem 2006; 49:4305-16. [PMID: 16821790 DOI: 10.1021/jm060338p] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A three-dimensional model of the AT1 receptor was constructed by means of a homology modeling procedure, using the X-ray structure of bovine rhodopsin as the initial template and taking into account the available site-directed mutagenesis data. The docking of losartan and its active metabolite EXP3174, followed by 1 ns of molecular dynamics (MD) simulation inserted into the phospholipid bilayer, suggested a different binding orientation for these antagonists from those previously proposed. Furthermore, the docking of several non-peptide antagonists was used as an alignment tool for the development of a three-dimensional quantitative structure-activity relationship (3D-QSAR) model, and the good results confirmed our binding hypothesis and the reliability of the model.
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Affiliation(s)
- Tiziano Tuccinardi
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, via Bonanno 6, 56126 Pisa, Italy
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35
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Miura SI, Fujino M, Hanzawa H, Kiya Y, Imaizumi S, Matsuo Y, Tomita S, Uehara Y, Karnik SS, Yanagisawa H, Koike H, Komuro I, Saku K. Molecular Mechanism Underlying Inverse Agonist of Angiotensin II Type 1 Receptor. J Biol Chem 2006; 281:19288-95. [PMID: 16690611 DOI: 10.1074/jbc.m602144200] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To delineate the molecular mechanism underlying the inverse agonist activity of olmesartan, a potent angiotensin II type 1 (AT1) receptor antagonist, we performed binding affinity studies and an inositol phosphate production assay. Binding affinity of olmesartan and its related compounds to wild-type and mutant AT1 receptors demonstrated that interactions between olmesartan and Tyr113, Lys199, His256, and Gln257 in the AT1 receptor were important. The inositol phosphate production assay of olmesartan and related compounds using mutant receptors indicated that the inverse agonist activity required two interactions, that between the hydroxyl group of olmesartan and Tyr113 in the receptor and that between the carboxyl group of olmesartan and Lys199 and His256 in the receptor. Gln257 was found to be important for the interaction with olmesartan but not for the inverse agonist activity. Based on these results, we constructed a model for the interaction between olmesartan and the AT1 receptor. Although the activation of G protein-coupled receptors is initiated by anti-clockwise rotation of transmembrane (TM) III and TM VI followed by changes in the conformation of the receptor, in this model, cooperative interactions between the hydroxyl group and Tyr113 in TM III and between the carboxyl group and His256 in TM VI were essential for the potent inverse agonist activity of olmesartan. We speculate that the specific interaction of olmesartan with these two TMs is essential for stabilizing the AT1 receptor in an inactive conformation. A better understanding of the molecular mechanisms of the inverse agonism could be useful for the development of new G protein-coupled receptor antagonists with inverse agonist activity.
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Affiliation(s)
- Shin-ichiro Miura
- Department of Cardiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan.
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36
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Ismail MAH, Barker S, Abou el-Ella DA, Abouzid KAM, Toubar RA, Todd MH. Design and synthesis of new tetrazolyl- and carboxy-biphenylylmethyl-quinazolin-4-one derivatives as angiotensin II AT1 receptor antagonists. J Med Chem 2006; 49:1526-35. [PMID: 16509571 DOI: 10.1021/jm050232e] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A series of novel quinazolin-4-ones was designed and their molecular modeling simulation fitting to a new HipHop 3D pharmacophore model using CATALYST was examined. Several compounds showed significant high simulation fit values. The designed compounds were synthesized and eight of them were biologically evaluated in vitro using an AT1 receptor binding assay, where compound XX competed weakly against radiolabeled Sar1Ile8-angiotensin II (Ang II) binding, compounds XIV and XXII showed moderate competition, and compound XXV showed almost equal ability to displace radiolabeled Sar1Ile8-Ang II binding to AT1 receptors as losartan. In vivo biological evaluation study of compounds XIV, XXII, and XXV on both normotensive and hypertensive rats revealed that compound XXV demonstrated higher hypotensive and antihypertensive activity than the reference compound losartan. To obtain a highly active compound from a candidate set of only eight tested compounds illustrates the power and utility of our pharmacophore model.
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Affiliation(s)
- Mohamed A H Ismail
- Pharmaceutical Chemistry Department, Faculty of Pharmacy, Ain Shams University, ElKhalifa ElMaamoon St., 11566, Abbasseya, Cairo, Egypt.
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37
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Mathiesen JM, Christopoulos A, Ulven T, Royer JF, Campillo M, Heinemann A, Pardo L, Kostenis E. On the Mechanism of Interaction of Potent Surmountable and Insurmountable Antagonists with the Prostaglandin D2 Receptor CRTH2. Mol Pharmacol 2006; 69:1441-53. [PMID: 16418339 DOI: 10.1124/mol.105.017681] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chemoattractant receptor-homologous molecule expressed on T helper 2 cells (CRTH2) has attracted interest as a potential therapeutic target in inflammatory diseases. Ramatroban, a thromboxane A2 receptor antagonist with clinical efficacy in allergic rhinitis, was recently found to also display potent CRTH2 antagonistic activity. Here, we present the pharmacological profile of three ramatroban analogs that differ chemically from ramatroban by either a single additional methyl group (TM30642), or an acetic acid instead of a propionic acid side chain (TM30643), or both modifications (TM30089). All three compounds bound to human CRTH2 stably expressed in human embryonic kidney 293 cells with nanomolar affinity. [3H]Prostaglandin D2 (PGD2) saturation analysis reveals that ramatroban and TM30642 decrease PGD2 affinity, whereas TM30643 and TM30089 exclusively depress ligand binding capacity (Bmax). Each of the three compounds acted as potent CRTH2 antagonists, yet the nature of their antagonism differed markedly. In functional assays measuring inhibition of PGD2-mediated 1) guanosine 5'-O-(3-thio)triphosphate binding, 2) beta-arrestin translocation, and 3) shape change of human eosinophils endogenously expressing CRTH2, ramatroban, and TM30642 produced surmountable antagonism and parallel rightward shifts of the PGD2 concentration-response curves. For TM30643 and TM30089, this shift was accompanied by a progressive reduction of maximal response. Binding analyses indicated that the functional insurmountability of TM30643 and TM30089 was probably related to long-lasting CRTH2 inhibition mediated via the orthosteric site of the receptor. A mechanistic understanding of insurmountability of CRTH2 antagonists could be fundamental for development of this novel class of anti-inflammatory drugs.
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38
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Baleanu-Gogonea C, Karnik S. Model of the whole rat AT1 receptor and the ligand-binding site. J Mol Model 2006; 12:325-37. [PMID: 16404618 DOI: 10.1007/s00894-005-0049-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Accepted: 07/22/2005] [Indexed: 10/25/2022]
Abstract
We present a three-dimensional model of the rat type 1 receptor (AT1) for the hormone angiotensin II (Ang II). Ang II and the AT1 receptor play a critical role in the cell-signaling process responsible for the actions of renin-angiotensin system in the regulation of blood pressure, water-electrolyte homeostasis and cell growth. Development of improved therapeutics would be significantly enhanced with the availability of a 3D-structure model for the AT1 receptor and of the binding site for agonists and antagonists. This model was constructed using a combination of computation and homology-modeling techniques starting with the experimentally determined three-dimensional structure of bovine rhodopsin (PDB#1F88) as a template. All 359 residues and two disulfide bonds in the rat AT1 receptor have been accounted for in this model. Ramachandran-map analysis and a 1 nanosecond molecular dynamics simulation of the solvated receptor with and without the bound ligand, Ang II, lend credence to the validity of the model. Docking calculations were performed with the agonist, Ang II and the antihypertensive antagonist, losartan. [Figure: see text].
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Affiliation(s)
- Camelia Baleanu-Gogonea
- Department of Molecular Cardiology at Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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Bond RA, Ijzerman AP. Recent developments in constitutive receptor activity and inverse agonism, and their potential for GPCR drug discovery. Trends Pharmacol Sci 2006; 27:92-6. [PMID: 16406086 DOI: 10.1016/j.tips.2005.12.007] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2005] [Revised: 11/21/2005] [Accepted: 12/15/2005] [Indexed: 11/18/2022]
Abstract
The concept of constitutively active G-protein-coupled receptors is now firmly rooted in receptor pharmacology. Many independent research groups have contributed to its acceptance since its introduction by Costa and Herz in 1989. This concept necessitated a revised ligand classification, and a new category of inverse agonists was introduced alongside existing agonist and antagonist ligands. Initially, it was hoped that new therapeutic modalities would become available. However, the drug industry has not adopted inverse agonism as a design criterion and instead accepted that some compounds emerge as (neutral) antagonists in compound screening, whereas other compounds possess inverse agonistic activity. In this article, we summarize aspects of the impact of constitutive activity on the drug-discovery process: for example, its use in orphan receptor assays, its link with pharmacogenetics and genomics, and its relevance for currently marketed drugs.
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Affiliation(s)
- Richard A Bond
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, 4800 Calhoun, Houston, TX 77204-5037, USA
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