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Vila-Julià G, Rubio-Martinez J, Perez JJ. Assessment of the bound conformation of bombesin to the BB1 and BB2 receptors. Int J Biol Macromol 2024; 255:127843. [PMID: 37956803 DOI: 10.1016/j.ijbiomac.2023.127843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/31/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023]
Abstract
Bombesin is an endogenous peptide involved in a wide spectrum of physiological activities ranging from satiety, control of circadian rhythm and thermoregulation in the central nervous system, to stimulation of gastrointestinal hormone release, activation of macrophages and effects on development in peripheral tissues. Actions of the peptide are mediated through the two high affinity G-protein coupled receptors BB1R and BB2R. Under pathophysiological conditions, these receptors are overexpressed in many different types of tumors, such as prostate cancer, breast cancer, small and non-small cell lung cancer and pancreatic cancer. This observation has been used for designing cell markers, but it has not been yet exploited for therapeutical purposes. Despite the enormous biological interest of the peptide, little is known about the stereochemical features that contribute to their activity. On the one hand, mutagenesis studies identified a few receptor residues important for high bombesin affinity and on the other, a few studies focused on the relevance of diverse residues of the peptide for receptor activation. Models of the peptide bound to BB1R and BB2R can be helpful to improve our understanding of the stereochemical features granting bombesin activity. Accordingly, the present study describes the computational process followed to construct such models by means of Steered Molecular Dynamics, using models of the peptide and its receptors. Present results provide new insights into the structure-activity relationships of bombesin and its receptors, as well as render an explanation for the differential binding affinity observed towards BB1R and BB2R. Finally, these models can be further exploited to help for designing novel small molecule peptidomimetics with improved pharmacokinetics profile.
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Affiliation(s)
- Guillem Vila-Julià
- Department of Materials Science and Physical Chemistry, University of Barcelona and the Institut de Recerca en Quimica Teorica i Computacional (IQTCUB), Barcelona, Spain; Department of Chemical Engineering, Universitat Politecnica de Catalunya- Barcelona Tech., Av. Diagonal, 647, 08028 Barcelona, Spain
| | - Jaime Rubio-Martinez
- Department of Materials Science and Physical Chemistry, University of Barcelona and the Institut de Recerca en Quimica Teorica i Computacional (IQTCUB), Barcelona, Spain
| | - Juan J Perez
- Department of Chemical Engineering, Universitat Politecnica de Catalunya- Barcelona Tech., Av. Diagonal, 647, 08028 Barcelona, Spain.
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2
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Rasaeifar B, Gomez-Gutierrez P, Perez JJ. New Insights into the Stereochemical Requirements of the Bombesin BB1 Receptor Antagonists Binding. Pharmaceuticals (Basel) 2020; 13:ph13080197. [PMID: 32824403 PMCID: PMC7463749 DOI: 10.3390/ph13080197] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 08/10/2020] [Accepted: 08/12/2020] [Indexed: 12/24/2022] Open
Abstract
Members of the family of bombesinlike peptides exert a wide range of biological activities both at the central nervous system and in peripheral tissues through at least three G-Protein Coupled Receptors: BB1, BB2 and BB3. Despite the number of peptide ligands already described, only a few small molecule binders have been disclosed so far, hampering a deeper understanding of their pharmacology. In order to have a deeper understanding of the stereochemical features characterizing binding to the BB1 receptor, we performed the molecular modeling study consisting of the construction of a 3D model of the receptor by homology modeling followed by a docking study of the peptoids PD168368 and PD176252 onto it. Analysis of the complexes permitted us to propose prospective bound conformations of the compounds, consistent with the experimental information available. Subsequently, we defined a pharmacophore describing minimal stereochemical requirements for binding to the BB1 receptor that was used in silico screening. This exercise yielded a set of small molecules that were purchased and tested, showing affinity to the BB1 but not to the BB2 receptor. These molecules exhibit scaffolds of diverse chemical families that can be used as a starting point for the development of novel BB1 antagonists.
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3
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Molecular features characterizing non-peptide selectivity to the human B1 and B2 bradykinin receptors. Bioorg Med Chem Lett 2018; 29:11-14. [PMID: 30466897 DOI: 10.1016/j.bmcl.2018.11.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 11/08/2018] [Accepted: 11/13/2018] [Indexed: 02/07/2023]
Abstract
Bradykinin is produced in response to inflammation, trauma, burns, shock, allergy and some cardiovascular diseases. Actions of this peptide are mediated through two different G-protein coupled receptors, named B1 and B2 that have different pharmacological characteristics. The former is up-regulated during inflammation episodes or tissue trauma whereas, the latter is constitutively expressed in a variety of cell types. In a previous work we have characterized the molecular features that explain the observed structure-activity results for both receptors by means of molecular modeling studies, using diverse ligands for both receptors. These results were summarized in the form of two different pharmacophores that provided new insights to be used for the design of novel molecules with antagonistic profile. In the present work, we compare these pharmacophores to understand the features that characterize ligand selectivity to the two bradykinin receptors. The study shows that most of the residues involved in the binding pocket are similar in both receptors and consequently are the pharmacophores obtained. The main difference between the two pharmacophores remains on point #5 that involves a polar moiety for the B1 receptor and an aromatic ring for the B2 receptor. Accordingly, analysis of the prospective bound conformation of several non-selective small molecule ligands of the bradykinin receptors permits to conclude that fulfilment of point#5 is a requirement to produce selective ligands. However, the study also shows that this is a necessary condition only, since ligands need also to be bulky enough to avoid binding to these receptors in diverse poses. These results provide new insights for a better understanding of the molecular features that ligands are required to exhibit to be selective bradykinin ligands.
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Lupala CS, Rasaeifar B, Gomez-Gutierrez P, Perez JJ. Using molecular dynamics for the refinement of atomistic models of GPCRs by homology modeling. J Biomol Struct Dyn 2017; 36:2436-2448. [PMID: 28728517 DOI: 10.1080/07391102.2017.1357503] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Despite GPCRs sharing a common seven helix bundle, analysis of the diverse crystallographic structures available reveal specific features that might be relevant for ligand design. Despite the number of crystallographic structures of GPCRs steadily increasing, there are still challenges that hamper the availability of new structures. In the absence of a crystallographic structure, homology modeling remains one of the important techniques for constructing 3D models of proteins. In the present study we investigated the use of molecular dynamics simulations for the refinement of GPCRs models constructed by homology modeling. Specifically, we investigated the relevance of template selection, ligand inclusion as well as the length of the simulation on the quality of the GPCRs models constructed. For this purpose we chose the crystallographic structure of the rat muscarinic M3 receptor as reference and constructed diverse atomistic models by homology modeling, using different templates. Specifically, templates used in the present work include the human muscarinic M2; the more distant human histamine H1 and the even more distant bovine rhodopsin as shown in the GPCRs phylogenetic tree. We also investigated the use or not of a ligand in the refinement process. Hence, we conducted the refinement process of the M3 model using the M2 muscarinic as template with tiotropium or NMS docked in the orthosteric site and compared with the results obtained with a model refined without any ligand bound.
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Affiliation(s)
- Cecylia S Lupala
- a Department of Chemical Engineering (ETSEIB) , Universitat Politecnica de Catalunya , Av. Diagonal, 647. 08028 Barcelona , Spain
| | - Bahareh Rasaeifar
- a Department of Chemical Engineering (ETSEIB) , Universitat Politecnica de Catalunya , Av. Diagonal, 647. 08028 Barcelona , Spain
| | - Patricia Gomez-Gutierrez
- a Department of Chemical Engineering (ETSEIB) , Universitat Politecnica de Catalunya , Av. Diagonal, 647. 08028 Barcelona , Spain
| | - Juan J Perez
- a Department of Chemical Engineering (ETSEIB) , Universitat Politecnica de Catalunya , Av. Diagonal, 647. 08028 Barcelona , Spain
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5
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Lupala CS, Gomez-Gutierrez P, Perez JJ. New insights into the stereochemical requirements of the bradykinin B1 receptor antagonists binding. J Mol Graph Model 2016; 68:184-196. [PMID: 27469392 DOI: 10.1016/j.jmgm.2016.06.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 06/17/2016] [Accepted: 06/17/2016] [Indexed: 02/01/2023]
Abstract
Bradykinin (BK) is a nonapeptide involved in several pathophysiological conditions including among others, septic and haemorrhagic shock, anaphylaxis, arthritis, rhinitis, asthma, inflammatory bowel disease. Accordingly, BK antagonists have long been sought after for therapeutic intervention. Action of BK is mediated through two different G-protein coupled receptors known as B1 and B2. Although there are several B1 antagonists reported in literature, their pharmacological profile is not yet optimal so that new molecules need to be discovered. In the present work we have constructed an atomistic model of the B1 receptor and docked diverse available non-peptide antagonists in order to get a deeper insight into the structure-activity relationships involving binding to this receptor. The model was constructed by homology modeling using the chemokine CXC4 and bovine rhodopsin receptors as template. The model was further refined using molecular dynamics for 600ns with the protein embedded in a POPC bilayer. From the refinement process we obtained an average structure that was used for docking studies using the Glide software. Antagonists selected for the docking studies include Compound 11, Compound 12, Chroman28, SSR240612, NPV-SAA164 and PS020990. The results of the docking study underline the role of specific receptor residues in ligand binding. The results of this study permitted to define a pharmacophore that describes the stereochemical requirements of antagonist binding, and can be used for the discovery of new compounds.
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Affiliation(s)
- Cecylia S Lupala
- Dept. of Chemical Engineering, Universitat Politecnica de Catalunya, ETSEIB. Av. Diagonal, 647, 08028 Barcelona, Spain
| | - Patricia Gomez-Gutierrez
- Dept. of Chemical Engineering, Universitat Politecnica de Catalunya, ETSEIB. Av. Diagonal, 647, 08028 Barcelona, Spain
| | - Juan J Perez
- Dept. of Chemical Engineering, Universitat Politecnica de Catalunya, ETSEIB. Av. Diagonal, 647, 08028 Barcelona, Spain.
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6
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Lupala CS, Gomez-Gutierrez P, Perez JJ. New insights into the stereochemical requirements of the bradykinin B2 receptor antagonists binding. J Comput Aided Mol Des 2015; 30:85-101. [DOI: 10.1007/s10822-015-9890-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 12/17/2015] [Indexed: 10/22/2022]
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7
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Laner M, Hünenberger PH. Phase-transition properties of glycerol–dipalmitate lipid bilayers investigated using molecular dynamics simulation. J Mol Graph Model 2015; 59:136-47. [DOI: 10.1016/j.jmgm.2015.04.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 04/21/2015] [Accepted: 04/22/2015] [Indexed: 11/29/2022]
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8
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Effect of methanol on the phase-transition properties of glycerol-monopalmitate lipid bilayers investigated using molecular dynamics simulations: In quest of the biphasic effect. J Mol Graph Model 2015; 55:85-104. [DOI: 10.1016/j.jmgm.2014.10.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 10/29/2014] [Accepted: 10/30/2014] [Indexed: 11/21/2022]
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9
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Reif MM, Oostenbrink C. Toward the correction of effective electrostatic forces in explicit-solvent molecular dynamics simulations: restraints on solvent-generated electrostatic potential and solvent polarization. Theor Chem Acc 2015; 134:2. [PMID: 26097404 PMCID: PMC4470580 DOI: 10.1007/s00214-014-1600-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 11/19/2014] [Indexed: 11/26/2022]
Abstract
Despite considerable advances in computing power, atomistic simulations under nonperiodic boundary conditions, with Coulombic electrostatic interactions and in systems large enough to reduce finite-size associated errors in thermodynamic quantities to within the thermal energy, are still not affordable. As a result, periodic boundary conditions, systems of microscopic size and effective electrostatic interaction functions are frequently resorted to. Ensuing artifacts in thermodynamic quantities are nowadays routinely corrected a posteriori, but the underlying configurational sampling still descends from spurious forces. The present study addresses this problem through the introduction of on-the-fly corrections to the physical forces during an atomistic molecular dynamics simulation. Two different approaches are suggested, where the force corrections are derived from special potential energy terms. In the first approach, the solvent-generated electrostatic potential sampled at a given atom site is restrained to a target value involving corrections for electrostatic artifacts. In the second approach, the long-range regime of the solvent polarization around a given atom site is restrained to the Born polarization, i.e., the solvent polarization corresponding to the ideal situation of a macroscopic system under nonperiodic boundary conditions and governed by Coulombic electrostatic interactions. The restraints are applied to the explicit-water simulation of a hydrated sodium ion, and the effect of the restraints on the structural and energetic properties of the solvent is illustrated. Furthermore, by means of the calculation of the charging free energy of a hydrated sodium ion, it is shown how the electrostatic potential restraint translates into the on-the-fly consideration of the corresponding free-energy correction terms. It is discussed how the restraints can be generalized to situations involving several solute particles. Although the present study considers a very simple system only, it is an important step toward the on-the-fly elimination of finite-size and approximate-electrostatic artifacts during atomistic molecular dynamics simulations.
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Affiliation(s)
- Maria M. Reif
- Institute for Molecular Modeling and Simulation, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria
| | - Chris Oostenbrink
- Institute for Molecular Modeling and Simulation, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria
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10
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Laner M, Horta BAC, Hünenberger PH. Long-timescale motions in glycerol-monopalmitate lipid bilayers investigated using molecular dynamics simulation. J Mol Graph Model 2014; 55:48-64. [PMID: 25437095 DOI: 10.1016/j.jmgm.2014.10.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 10/28/2014] [Accepted: 10/30/2014] [Indexed: 10/24/2022]
Abstract
The occurrence of long-timescale motions in glycerol-1-monopalmitate (GMP) lipid bilayers is investigated based on previously reported 600 ns molecular dynamics simulations of a 2×8×8 GMP bilayer patch in the temperature range 302-338 K, performed at three different hydration levels, or in the presence of the cosolutes methanol or trehalose at three different concentrations. The types of long-timescale motions considered are: (i) the possible phase transitions; (ii) the precession of the relative collective tilt-angle of the two leaflets in the gel phase; (iii) the trans-gauche isomerization of the dihedral angles within the lipid aliphatic tails; and (iv) the flipping of single lipids across the two leaflets. The results provide a picture of GMP bilayers involving a rich spectrum of events occurring on a wide range of timescales, from the 100-ps range isomerization of single dihedral angles, via the 100-ns range of tilt precession motions, to the multi-μs range of phase transitions and lipid-flipping events.
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Affiliation(s)
- Monika Laner
- Laboratory of Physical Chemistry, ETH Zürich, Zürich, Switzerland.
| | - Bruno A C Horta
- Laboratory of Physical Chemistry, ETH Zürich, Zürich, Switzerland; Dpto. de Engenharia Elétrica, PUC-Rio, Rio de Janeiro, Brazil; Dpto. de Ciências Biológicas, UEZO, Rio de Janeiro, Brazil.
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11
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Effect of the cosolutes trehalose and methanol on the equilibrium and phase-transition properties of glycerol-monopalmitate lipid bilayers investigated using molecular dynamics simulations. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2014; 43:517-44. [DOI: 10.1007/s00249-014-0982-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 07/16/2014] [Accepted: 07/24/2014] [Indexed: 10/24/2022]
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12
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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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13
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Laner M, Horta BA, Hünenberger PH. Phase-transition properties of glycerol-monopalmitate lipid bilayers investigated by molecular dynamics simulation: influence of the system size and force-field parameters. MOLECULAR SIMULATION 2013. [DOI: 10.1080/08927022.2012.755526] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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14
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Lama D, Modi V, Sankararamakrishnan R. Behavior of solvent-exposed hydrophobic groove in the anti-apoptotic Bcl-XL protein: clues for its ability to bind diverse BH3 ligands from MD simulations. PLoS One 2013; 8:e54397. [PMID: 23468841 PMCID: PMC3585337 DOI: 10.1371/journal.pone.0054397] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 12/13/2012] [Indexed: 11/19/2022] Open
Abstract
Bcl-XL is a member of Bcl-2 family of proteins involved in the regulation of intrinsic pathway of apoptosis. Its overexpression in many human cancers makes it an important target for anti-cancer drugs. Bcl-XL interacts with the BH3 domain of several pro-apoptotic Bcl-2 partners. This helical bundle protein has a pronounced hydrophobic groove which acts as a binding region for the BH3 domains. Eight independent molecular dynamics simulations of the apo/holo forms of Bcl-XL were carried out to investigate the behavior of solvent-exposed hydrophobic groove. The simulations used either a twin-range cut-off or particle mesh Ewald (PME) scheme to treat long-range interactions. Destabilization of the BH3 domain-containing helix H2 was observed in all four twin-range cut-off simulations. Most of the other major helices remained stable. The unwinding of H2 can be related to the ability of Bcl-XL to bind diverse BH3 ligands. The loss of helical character can also be linked to the formation of homo- or hetero-dimers in Bcl-2 proteins. Several experimental studies have suggested that exposure of BH3 domain is a crucial event before they form dimers. Thus unwinding of H2 seems to be functionally very important. The four PME simulations, however, revealed a stable helix H2. It is possible that the H2 unfolding might occur in PME simulations at longer time scales. Hydrophobic residues in the hydrophobic groove are involved in stable interactions among themselves. The solvent accessible surface areas of bulky hydrophobic residues in the groove are significantly buried by the loop LB connecting the helix H2 and subsequent helix. These observations help to understand how the hydrophobic patch in Bcl-XL remains stable in the solvent-exposed state. We suggest that both the destabilization of helix H2 and the conformational heterogeneity of loop LB are important factors for binding of diverse ligands in the hydrophobic groove of Bcl-XL.
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Affiliation(s)
- Dilraj Lama
- Department of Biological Sciences & Bioengineering, Indian Institute of Technology Kanpur, Kanpur, India
| | - Vivek Modi
- Department of Biological Sciences & Bioengineering, Indian Institute of Technology Kanpur, Kanpur, India
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15
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Cordomí A, Perez JJ. Structural Rearrangements of Rhodopsin Subunits in a Dimer Complex: a Molecular Dynamics Simulation Study. J Biomol Struct Dyn 2012; 27:127-47. [DOI: 10.1080/07391102.2009.10507303] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Arnau Cordomí
- a Dept d'Enginyeria Química , Technical University of Catalonia (UPC), ETS d'Enginyeria Industrial , Av. Diagonal 647, 08028 , Barcelona , Spain
| | - Juan J. Perez
- a Dept d'Enginyeria Química , Technical University of Catalonia (UPC), ETS d'Enginyeria Industrial , Av. Diagonal 647, 08028 , Barcelona , Spain
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16
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Cordomí A, Caltabiano G, Pardo L. Membrane Protein Simulations Using AMBER Force Field and Berger Lipid Parameters. J Chem Theory Comput 2012; 8:948-58. [PMID: 26593357 DOI: 10.1021/ct200491c] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
AMBER force fields are among the most commonly used in molecular dynamics (MD) simulations of proteins. Unfortunately, they lack a specific set of lipid parameters, thus limiting its use in membrane protein simulations. In order to overcome this limitation we assessed whether the widely used united-atom lipid parameters described by Berger and co-workers could be used in conjunction with AMBER force fields in simulations of membrane proteins. Thus, free energies of solvation in water and in cyclohexane, and free energies of water to cyclohexane transfer, were computed by thermodynamic integration procedures for neutral amino acid side-chains employing AMBER99, AMBER03, and OPLS-AA amino acid force fields. In addition, MD simulations of three membrane proteins in a POPC lipid bilayer, the β2 adrenergic G protein-coupled receptor, Aquaporin-1, and the outer membrane protein Omp32, were performed with the aim of comparing the AMBER99SB/Berger combination of force fields with the OPLS-AA/Berger combination. We have shown that AMBER99SB and Berger force fields are compatible, they provide reliable free energy estimations relative to experimental values, and their combination properly describes both membrane and protein structural properties. We then suggest that the AMBER99SB/Berger combination is a reliable choice for the simulation of membrane proteins, which links the easiness of ligand parametrization and the ability to reproduce secondary structure of AMBER99SB force field with the largely validated Berger lipid parameters.
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Affiliation(s)
- Arnau Cordomí
- Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona , 08193 Bellaterra, Spain
| | - Gianluigi Caltabiano
- Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona , 08193 Bellaterra, Spain
| | - Leonardo Pardo
- Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona , 08193 Bellaterra, Spain
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17
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Cerezo J, Zúñiga J, Bastida A, Requena A, Cerón-Carrasco JP. Atomistic Molecular Dynamics Simulations of the Interactions of Oleic and 2-Hydroxyoleic Acids with Phosphatidylcholine Bilayers. J Phys Chem B 2011; 115:11727-38. [DOI: 10.1021/jp203498x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Javier Cerezo
- Departamento de Química Física, Universidad de Murcia, 30100 Murcia, Spain
| | - José Zúñiga
- Departamento de Química Física, Universidad de Murcia, 30100 Murcia, Spain
| | - Adolfo Bastida
- Departamento de Química Física, Universidad de Murcia, 30100 Murcia, Spain
| | - Alberto Requena
- Departamento de Química Física, Universidad de Murcia, 30100 Murcia, Spain
| | - José Pedro Cerón-Carrasco
- CEISAM, UMR CNRS 6230, BP 92208, Université de Nantes, 2, rue de la Houssiniére, 44322 Nantes Cedex 3, France
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18
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Fuchs PFJ. Molecular dynamics of membrane peptides and proteins: principles and comparison to experimental data. Methods Mol Biol 2010; 654:403-21. [PMID: 20665278 DOI: 10.1007/978-1-60761-762-4_21] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Molecular dynamics (MD) simulation is a standard tool used to assess the motion of biomolecules at atomic resolution. It requires a so-called "force field" that allows the evaluation of an empirical energy from the 3D coordinates of the atoms in the system. In this chapter, the application of MD simulations to membrane proteins and peptides is described with a particular emphasis on the comparison of MD results to experimental data. Such a comparison can be used either for (1) validating the results of a simulation, (2) interpreting an experiment at the atomic level, or (3) calibrating the force field. This last step is particularly important for the use of MD as a predictive tool. As an illustration, a comparison of (2)H NMR experiments to MD simulations of a transmembrane peptide is presented and discussed.
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Affiliation(s)
- Patrick F J Fuchs
- Equipe de Bioinformatique Génomique et Moléculaire, INSERM UMR-S726, Institut National de Transfusion Sanguine, Université Paris Diderot - Paris 7, Paris, France.
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19
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Horta BAC, de Vries AH, Hünenberger PH. Simulating the Transition between Gel and Liquid-Crystal Phases of Lipid Bilayers: Dependence of the Transition Temperature on the Hydration Level. J Chem Theory Comput 2010; 6:2488-500. [DOI: 10.1021/ct100200w] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bruno A. C. Horta
- Laboratory of Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland, and University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Alex H. de Vries
- Laboratory of Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland, and University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Philippe H. Hünenberger
- Laboratory of Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland, and University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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20
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Cordomí A, Prades J, Frau J, Vögler O, Funari SS, Perez JJ, Escribá PV, Barceló F. Interactions of fatty acids with phosphatidylethanolamine membranes: X-ray diffraction and molecular dynamics studies. J Lipid Res 2009; 51:1113-24. [PMID: 19965616 DOI: 10.1194/jlr.m003012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An experimental and theoretical study on 1,2-dielaidoyl-sn-glycero-3-phosphoethanolamine (DEPE) membranes containing fatty acids (FAs) was performed by means of X-ray diffraction analysis and molecular dynamics (MD) simulations. The study was aimed at understanding the interactions of several structurally related FAs with biomembranes, which is necessary for further rational lipid drug design in membrane-lipid therapy. The main effect of FAs was to promote the formation of a H(II) phase, despite a stabilization of the coexisting L(alpha) + H(II) phases. Derivatives of OA exhibited a specific density profile in the direction perpendicular to the bilayer that reflects differences in the relative localization of the carboxylate group within the polar region of the membrane as well as in the degree of membrane penetration of the FA acyl chain. Hydroxyl and methyl substituents at carbon-2 in the FA acyl chain were identified as effective modulators of the position of carboxylate group in the lipid bilayer. Our data highlight the specific potential of each FA in modulating the membrane structure properties.
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Affiliation(s)
- Arnau Cordomí
- Department d'Enginyeria Química, Technical University of Catalonia, Barcelona, Spain
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21
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Reif MM, Kräutler V, Kastenholz MA, Daura X, Hünenberger PH. Molecular dynamics simulations of a reversibly folding beta-heptapeptide in methanol: influence of the treatment of long-range electrostatic interactions. J Phys Chem B 2009; 113:3112-28. [PMID: 19228001 DOI: 10.1021/jp807421a] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Eight 100-ns molecular dynamics simulations of a beta-heptapeptide in methanol at 340 K (within cubic periodic computational boxes of about 6-nm edge) are reported and compared. These simulations were performed with three different charge-state combinations at the peptide termini, one of them with or without a neutralizing chloride counterion, and using either the lattice-sum (LS) or reaction-field (RF) scheme to handle electrostatic interactions. The choice of the electrostatic scheme has essentially no influence on the folding-unfolding equilibrium when the peptide termini are uncharged and only a small influence when the peptide is positively charged at its N-terminus (with or without inclusion of a neutralizing chloride counterion). However, when the peptide is zwitterionic, the LS scheme leads to preferential sampling of the high-dipole folded helical state, whereas the RF scheme leads to preferential sampling of a low-dipole unfolded salt-bridged state. A continuum electrostatics analysis based on the sampled configurations (zwitterionic case) suggests that the LS scheme stabilizes the helical state through artificial periodicity, but that the magnitude of this perturbation is essentially negligible (compared to the thermal energy) for the large box size and relatively polar solvent considered. The results thus provide clear evidence (continuum electrostatics analysis) for the absence of LS artifacts and some indications (still not definitive because of the limited sampling of the folding-unfolding transition) for the presence of RF artifacts in this specific system.
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Affiliation(s)
- Maria M Reif
- Laboratory of Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland
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22
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Devireddy RV. Statistical thermodynamics of biomembranes. Cryobiology 2009; 60:80-90. [PMID: 19460363 DOI: 10.1016/j.cryobiol.2009.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 04/28/2009] [Accepted: 05/07/2009] [Indexed: 10/20/2022]
Abstract
An overview of the major issues involved in the statistical thermodynamic treatment of phospholipid membranes at the atomistic level is summarized: thermodynamic ensembles, initial configuration (or the physical system being modeled), force field representation as well as the representation of long-range interactions. This is followed by a description of the various ways that the simulated ensembles can be analyzed: area of the lipid, mass density profiles, radial distribution functions (RDFs), water orientation profile, deuterium order parameter, free energy profiles and void (pore) formation; with particular focus on the results obtained from our recent molecular dynamic (MD) simulations of phospholipids interacting with dimethylsulfoxide (Me(2)SO), a commonly used cryoprotective agent (CPA).
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Affiliation(s)
- Ram V Devireddy
- Department of Mechanical Engineering, Louisiana State University, 2508 Patrick F. Taylor Hall, Baton Rouge, LA 70803, USA.
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23
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Toledo D, Cordomí A, Proietti MG, Benfatto M, del Valle LJ, Pérez JJ, Garriga P, Sepulcre F. Structural Characterization of a Zinc High-affinity Binding Site in Rhodopsin. Photochem Photobiol 2009; 85:479-84. [DOI: 10.1111/j.1751-1097.2008.00529.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Cordomí A, Ramon E, Garriga P, Perez JJ. Molecular Dynamics Simulations of Rhodopsin Point Mutants at the Cytoplasmic Side of Helices 3 and 6. J Biomol Struct Dyn 2008; 25:573-87. [DOI: 10.1080/07391102.2008.10507204] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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25
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Cordomí A, Edholm O, Perez JJ. Effect of ions on a dipalmitoyl phosphatidylcholine bilayer. a molecular dynamics simulation study. J Phys Chem B 2008; 112:1397-408. [PMID: 18193856 DOI: 10.1021/jp073897w] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effect of physiological concentrations of different chlorides on the structure of a dipalmitoyl phosphatidylcholine (DPPC) bilayer has been investigated through atomistic molecular dynamics simulations. These calculations provide support to the concept that Li+, Na+, Ca2+, Mg2+, Sr2+, Ba2+, and Ac3+, but not K+, bind to the lipid-head oxygens. Ion binding exhibits an influence on lipid order, area per lipid, orientation of the lipid head dipole, the charge distribution in the system, and therefore the electrostatic potential across the head-group region of the bilayer. These structural effects are sensitive to the specific characteristics of each cation, i.e., radius, charge, and coordination properties. These results provide evidence aimed at shedding some light into the apparent contradictions among different studies reported recently regarding the ordering effect of ions on zwitterionic phosphatidylcholine lipid bilayers.
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Affiliation(s)
- Arnau Cordomí
- Department of Chemical Engineering, Technical University of Catalonia (UPC), Av. Diagonal 647, 08028 Barcelona, Spain
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26
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Cordomí A, Perez JJ. Molecular Dynamics Simulations of Rhodopsin in Different One-Component Lipid Bilayers. J Phys Chem B 2007; 111:7052-63. [PMID: 17530884 DOI: 10.1021/jp0707788] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Four 20 ns molecular dynamic simulations of rhodopsin embedded in different one-component lipid bilayers have been carried out to ascertain the importance of membrane lipids on the protein structure. Specifically, dimyristoyl phosphatidylcholine (DMPC), dipalmitoyl phosphatidylcholine (DPPC), palmitoyl oleoyl phosphatidylcholine (POPC), and palmitoyl linoleyl phosphatidylcholine (PLPC) lipid bilayers have been considered for the present work. The results reported here provide information on the hydrophobic matching between the protein and the bilayer and about the differential effects of the protein on the thickness of the different membranes. Furthermore, a careful analysis of the individual protein-lipid interactions permits the identification of residues that exhibit permanent interactions with atoms of the lipid environment that may putatively act as hooks of the protein to the membrane. The analysis of the trajectories also provides information about the effect of the bilayer on the protein structure, including secondary structural elements, salt bridges, and rigid-body motions.
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Affiliation(s)
- Arnau Cordomí
- Dept d'Enginyeria Química, Technical University of Catalonia UPC, Barcelona, Spain.
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27
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Ramon E, Cordomí A, Bosch L, Zernii EY, Senin II, Manyosa J, Philippov PP, Pérez JJ, Garriga P. Critical role of electrostatic interactions of amino acids at the cytoplasmic region of helices 3 and 6 in rhodopsin conformational properties and activation. J Biol Chem 2007; 282:14272-82. [PMID: 17322302 DOI: 10.1074/jbc.m611091200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cytoplasmic sides of transmembrane helices 3 and 6 of G-protein-coupled receptors are connected by a network of ionic interactions that play an important role in maintaining its inactive conformation. To investigate the role of such a network in rhodopsin structure and function, we have constructed single mutants at position 134 in helix 3 and at positions 247 and 251 in helix 6, as well as combinations of these to obtain double mutants involving the two helices. These mutants have been expressed in COS-1 cells, immunopurified using the rho-1D4 antibody, and studied by UV-visible spectrophotometry. Most of the single mutations did not affect chromophore formation, but double mutants, especially those involving the T251K mutant, resulted in low yield of protein and impaired 11-cis-retinal binding. Single mutants E134Q, E247Q, and E247A showed the ability to activate transducin in the dark, and E134Q and E247A enhanced activation upon illumination, with regard to wild-type rhodopsin. Mutations E247A and T251A (in E134Q/E247A and E134Q/T251A double mutants) resulted in enhanced activation compared with the single E134Q mutant in the dark. A role for Thr(251) in this network is proposed for the first time in rhodopsin. As a result of these mutations, alterations in the hydrogen bond interactions between the amino acid side chains at the cytoplasmic region of transmembrane helices 3 and 6 have been observed using molecular dynamics simulations. Our combined experimental and modeling results provide new insights into the details of the structural determinants of the conformational change ensuing photoactivation of rhodopsin.
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Affiliation(s)
- Eva Ramon
- Centre de Biotecnologia Molecular, Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, 08222 Terrassa, Catalonia, Spain
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