1
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González-Cuevas JA, Argüello R, Florentin M, André FM, Mir LM. Experimental and Theoretical Brownian Dynamics Analysis of Ion Transport During Cellular Electroporation of E. coli Bacteria. Ann Biomed Eng 2024; 52:103-123. [PMID: 37651029 DOI: 10.1007/s10439-023-03353-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 08/15/2023] [Indexed: 09/01/2023]
Abstract
Escherichia coli bacterium is a rod-shaped organism composed of a complex double membrane structure. Knowledge of electric field driven ion transport through both membranes and the evolution of their induced permeabilization has important applications in biomedical engineering, delivery of genes and antibacterial agents. However, few studies have been conducted on Gram-negative bacteria in this regard considering the contribution of all ion types. To address this gap in knowledge, we have developed a deterministic and stochastic Brownian dynamics model to simulate in 3D space the motion of ions through pores formed in the plasma membranes of E. coli cells during electroporation. The diffusion coefficient, mobility, and translation time of Ca2+, Mg2+, Na+, K+, and Cl- ions within the pore region are estimated from the numerical model. Calculations of pore's conductance have been validated with experiments conducted at Gustave Roussy. From the simulations, it was found that the main driving force of ionic uptake during the pulse is the one due to the externally applied electric field. The results from this work provide a better understanding of ion transport during electroporation, aiding in the design of electrical pulses for maximizing ion throughput, primarily for application in cancer treatment.
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Affiliation(s)
- Juan A González-Cuevas
- School of Engineering, National University of Asunción, Campus San Lorenzo, 2169, San Lorenzo, Paraguay.
| | - Ricardo Argüello
- School of Engineering, National University of Asunción, Campus San Lorenzo, 2169, San Lorenzo, Paraguay
| | - Marcos Florentin
- School of Chemistry, National University of Asunción, Campus San Lorenzo, 2169, San Lorenzo, Paraguay
| | - Franck M André
- Université Paris-Saclay, CNRS, Gustave Roussy, UMR 9018 METSY, 94805, Villejuif, France
| | - Lluis M Mir
- Université Paris-Saclay, CNRS, Gustave Roussy, UMR 9018 METSY, 94805, Villejuif, France
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2
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Mostofian B, Martin HJ, Razavi A, Patel S, Allen B, Sherman W, Izaguirre JA. Targeted Protein Degradation: Advances, Challenges, and Prospects for Computational Methods. J Chem Inf Model 2023; 63:5408-5432. [PMID: 37602861 PMCID: PMC10498452 DOI: 10.1021/acs.jcim.3c00603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Indexed: 08/22/2023]
Abstract
The therapeutic approach of targeted protein degradation (TPD) is gaining momentum due to its potentially superior effects compared with protein inhibition. Recent advancements in the biotech and pharmaceutical sectors have led to the development of compounds that are currently in human trials, with some showing promising clinical results. However, the use of computational tools in TPD is still limited, as it has distinct characteristics compared with traditional computational drug design methods. TPD involves creating a ternary structure (protein-degrader-ligase) responsible for the biological function, such as ubiquitination and subsequent proteasomal degradation, which depends on the spatial orientation of the protein of interest (POI) relative to E2-loaded ubiquitin. Modeling this structure necessitates a unique blend of tools initially developed for small molecules (e.g., docking) and biologics (e.g., protein-protein interaction modeling). Additionally, degrader molecules, particularly heterobifunctional degraders, are generally larger than conventional small molecule drugs, leading to challenges in determining drug-like properties like solubility and permeability. Furthermore, the catalytic nature of TPD makes occupancy-based modeling insufficient. TPD consists of multiple interconnected yet distinct steps, such as POI binding, E3 ligase binding, ternary structure interactions, ubiquitination, and degradation, along with traditional small molecule properties. A comprehensive set of tools is needed to address the dynamic nature of the induced proximity ternary complex and its implications for ubiquitination. In this Perspective, we discuss the current state of computational tools for TPD. We start by describing the series of steps involved in the degradation process and the experimental methods used to characterize them. Then, we delve into a detailed analysis of the computational tools employed in TPD. We also present an integrative approach that has proven successful for degrader design and its impact on project decisions. Finally, we examine the future prospects of computational methods in TPD and the areas with the greatest potential for impact.
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Affiliation(s)
- Barmak Mostofian
- OpenEye, Cadence Molecular Sciences, Boston, Massachusetts 02114 United States
| | - Holli-Joi Martin
- Laboratory
for Molecular Modeling, Division of Chemical Biology and Medicinal
Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599 United States
| | - Asghar Razavi
- ENKO
Chem, Inc, Mystic, Connecticut 06355 United States
| | - Shivam Patel
- Psivant
Therapeutics, Boston, Massachusetts 02210 United States
| | - Bryce Allen
- Differentiated
Therapeutics, San Diego, California 92056 United States
| | - Woody Sherman
- Psivant
Therapeutics, Boston, Massachusetts 02210 United States
| | - Jesus A Izaguirre
- Differentiated
Therapeutics, San Diego, California 92056 United States
- Atommap
Corporation, New York, New York 10013 United States
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3
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Alford RF, Samanta R, Gray JJ. Diverse Scientific Benchmarks for Implicit Membrane Energy Functions. J Chem Theory Comput 2021; 17:5248-5261. [PMID: 34310137 DOI: 10.1021/acs.jctc.0c00646] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Energy functions are fundamental to biomolecular modeling. Their success depends on robust physical formalisms, efficient optimization, and high-resolution data for training and validation. Over the past 20 years, progress in each area has advanced soluble protein energy functions. Yet, energy functions for membrane proteins lag behind due to sparse and low-quality data, leading to overfit tools. To overcome this challenge, we assembled a suite of 12 tests on independent data sets varying in size, diversity, and resolution. The tests probe an energy function's ability to capture membrane protein orientation, stability, sequence, and structure. Here, we present the tests and use the franklin2019 energy function to demonstrate them. We then identify areas for energy function improvement and discuss potential future integration with machine-learning-based optimization methods. The tests are available through the Rosetta Benchmark Server (https://benchmark.graylab.jhu.edu/) and GitHub (https://github.com/rfalford12/Implicit-Membrane-Energy-Function-Benchmark).
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Affiliation(s)
- Rebecca F Alford
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, United States
| | - Rituparna Samanta
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, United States
| | - Jeffrey J Gray
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, United States.,Program in Molecular Biophysics, Johns Hopkins University, Baltimore, Maryland, United States
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4
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Lomize AL, Schnitzer KA, Todd SC, Pogozheva ID. Thermodynamics-Based Molecular Modeling of α-Helices in Membranes and Micelles. J Chem Inf Model 2021; 61:2884-2896. [PMID: 34029472 DOI: 10.1021/acs.jcim.1c00161] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Folding of Membrane-Associated Peptides (FMAP) method was developed for modeling α-helix formation by linear peptides in micelles and lipid bilayers. FMAP 2.0 identifies locations of α-helices in the amino acid sequence, generates their three-dimensional models in planar bilayers or spherical micelles, and estimates their thermodynamic stabilities and tilt angles, depending on temperature and pH. The method was tested for 723 peptides (926 data points) experimentally studied in different environments and for 170 single-pass transmembrane (TM) proteins with available crystal structures. FMAP 2.0 detected more than 95% of experimentally observed α-helices with an average error in helix end determination of around 2, 3, 4, and 5 residues per helix for peptides in water, micelles, bilayers, and TM proteins, respectively. Helical and nonhelical residue states were predicted with an accuracy from 0.86 to 0.96, and the Matthews correlation coefficient was from 0.64 to 0.88 depending on the environment. Experimental micelle- and membrane-binding energies and tilt angles of peptides were reproduced with a root-mean-square deviation of around 2 kcal/mol and 7°, respectively. The TM and non-TM states of hydrophobic and pH-triggered α-helical peptides in various lipid bilayers were reproduced in more than 95% of cases. The FMAP 2.0 web server (https://membranome.org/fmap) is publicly available to explore the structural polymorphism of antimicrobial, cell-penetrating, fusion, and other membrane-binding peptides, which is important for understanding the mechanisms of their biological activities.
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Affiliation(s)
- Andrei L Lomize
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109-1065, United States
| | - Kevin A Schnitzer
- Department of Electrical Engineering and Computer Science, College of Engineering, University of Michigan, 1221 Beal Avenue, Ann Arbor, Michigan 48109-2102, United States
| | - Spencer C Todd
- Department of Electrical Engineering and Computer Science, College of Engineering, University of Michigan, 1221 Beal Avenue, Ann Arbor, Michigan 48109-2102, United States
| | - Irina D Pogozheva
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109-1065, United States
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5
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Asymmetric opening of the homopentameric 5-HT 3A serotonin receptor in lipid bilayers. Nat Commun 2021; 12:1074. [PMID: 33594077 PMCID: PMC7887223 DOI: 10.1038/s41467-021-21016-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 01/06/2021] [Indexed: 12/13/2022] Open
Abstract
Pentameric ligand-gated ion channels (pLGICs) of the Cys-loop receptor family are key players in fast signal transduction throughout the nervous system. They have been shown to be modulated by the lipid environment, however the underlying mechanism is not well understood. We report three structures of the Cys-loop 5-HT3A serotonin receptor (5HT3R) reconstituted into saposin-based lipid bilayer discs: a symmetric and an asymmetric apo state, and an asymmetric agonist-bound state. In comparison to previously published 5HT3R conformations in detergent, the lipid bilayer stabilises the receptor in a more tightly packed, ‘coupled’ state, involving a cluster of highly conserved residues. In consequence, the agonist-bound receptor conformation adopts a wide-open pore capable of conducting sodium ions in unbiased molecular dynamics (MD) simulations. Taken together, we provide a structural basis for the modulation of 5HT3R by the membrane environment, and a model for asymmetric activation of the receptor. Pentameric ligand-gated ion channels (pLGICs) are key players in neurotransmission and have been shown to be modulated by the lipid environment, however the underlying mechanism is not well understood. Here, the authors report structures of the pLGIC 5-HT3A serotonin receptor reconstituted into lipid bilayer discs and reveal lipid–protein interactions as well as asymmetric activation of the homopentameric receptor.
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6
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Chan HC, Xu Y, Tan L, Vogel H, Cheng J, Wu D, Yuan S. Enhancing the Signaling of GPCRs via Orthosteric Ions. ACS CENTRAL SCIENCE 2020; 6:274-282. [PMID: 32123746 PMCID: PMC7047428 DOI: 10.1021/acscentsci.9b01247] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Indexed: 05/02/2023]
Abstract
G protein-coupled receptors play essential roles in cellular processes such as neuronal signaling, vision, olfaction, tasting, and metabolism. As GPCRs are the most important drug targets, understanding their interactions with ligands is of utmost importance for discovering related new medicines. In many GPCRs, an allosteric sodium ion next to the highly conserved residue D2.50 has been proposed to stabilize the inactive receptor state by mediating interactions between transmembrane helices. Here, we probed the existence of internal and functionally important sodium ions in the dopamine D2 receptor, using molecular dynamics simulations. Besides a new sodium ion at the allosteric ligand binding site, we discovered an additional sodium ion, located close to the orthosteric ligand binding site. Through cell-based activation assays, the signaling of D2 receptor with site-specific mutations was tested against a series of chemically modified agonists. We concluded an important structural role of this newly discovered orthosteric sodium ion in modulating the receptor signaling: It enables the coordination of a polar residue in the ligand binding site with an appropriately designed agonist molecule. An identical interaction was also observed in a recently released high-resolution crystal structure of mu-opioid receptor, which was reresolved in this work. Probably because of similar interactions, various metal ions have been found to increase the signaling of many other GPCRs. This unique principle and strategy could be used to optimize the drug activity of GPCR. Our findings open a new mechanistic opportunity of GPCR signaling and help design the next generation of drugs targeting GPCRs.
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Affiliation(s)
- H. C.
Stephen Chan
- Shenzhen
Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Yueming Xu
- iHuman
Institute, ShanghaiTech University, Shanghai 201210, China
| | - Liang Tan
- iHuman
Institute, ShanghaiTech University, Shanghai 201210, China
| | - Horst Vogel
- Shenzhen
Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- Institute
of Chemical Sciences and Engineering, Ecole
Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Jianjun Cheng
- iHuman
Institute, ShanghaiTech University, Shanghai 201210, China
- E-mail:
| | - Dong Wu
- iHuman
Institute, ShanghaiTech University, Shanghai 201210, China
- E-mail:
| | - Shuguang Yuan
- Shenzhen
Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- E-mail:
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7
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Lomize AL, Pogozheva ID. Physics-Based Method for Modeling Passive Membrane Permeability and Translocation Pathways of Bioactive Molecules. J Chem Inf Model 2019; 59:3198-3213. [PMID: 31259555 DOI: 10.1021/acs.jcim.9b00224] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Assessment of permeability is a critical step in the drug development process for selection of drug candidates with favorable ADME properties. We have developed a novel physics-based method for fast computational modeling of passive permeation of diverse classes of molecules across lipid membranes. The method is based on heterogeneous solubility-diffusion theory and operates with all-atom 3D structures of solutes and the anisotropic solvent model of the lipid bilayer characterized by transbilayer profiles of dielectric and hydrogen bonding capacity parameters. The optimal translocation pathway of a solute is determined by moving an ensemble of representative conformations of the molecule through the dioleoyl-phosphatidylcholine (DOPC) bilayer and optimizing their rotational orientations in every point of the transmembrane trajectory. The method calculates (1) the membrane-bound state of the solute molecule; (2) free energy profile of the solute along the permeation pathway; and (3) the permeability coefficient obtained by integration over the transbilayer energy profile and assuming a constant size-dependent diffusivity along the membrane normal. The accuracy of the predictions was evaluated against experimental permeability coefficients measured in pure lipid membranes (for 78 compounds, R2 was 0.88 and rmse was 1.15 log units), PAMPA-DS (for 280 compounds, R2 was 0.75 and rmse was 1.59 log units), BBB (for 182 compounds, R2 was 0.69 and rmse was 0.87 log units), and Caco-2/MDCK assays (for 165 compounds, R2 was 0.52 and rmse was 0.89 log units).
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Affiliation(s)
- Andrei L Lomize
- Department of Medicinal Chemistry, College of Pharmacy , University of Michigan , 428 Church Street , Ann Arbor , Michigan 48109-1065 , United States
| | - Irina D Pogozheva
- Department of Medicinal Chemistry, College of Pharmacy , University of Michigan , 428 Church Street , Ann Arbor , Michigan 48109-1065 , United States
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8
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Razzokov J, Naderi S, van der Schoot P. Nanoscale insight into silk-like protein self-assembly: effect of design and number of repeat units. Phys Biol 2018; 15:066010. [PMID: 30124438 DOI: 10.1088/1478-3975/aadb5e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
By means of replica exchange molecular dynamics simulations we investigate how the length of a silk-like, alternating diblock oligopeptide influences its secondary and quaternary structure. We carry out simulations for two protein sizes consisting of three and five blocks, and study the stability of a single protein, a dimer, a trimer and a tetramer. Initial configurations of our simulations are β-roll and β-sheet structures. We find that for the triblock the secondary and quaternary structures upto and including the tetramer are unstable: the proteins melt into random coil structures and the aggregates disassemble either completely or partially. We attribute this to the competition between conformational entropy of the proteins and the formation of hydrogen bonds and hydrophobic interactions between proteins. This is confirmed by our simulations on the pentablock proteins, where we find that, as the number of monomers in the aggregate increases, individual monomers form more hydrogen bonds whereas their solvent accessible surface area decreases. For the pentablock β-sheet protein, the monomer and the dimer melt as well, although for the β-roll protein only the monomer melts. For both trimers and tetramers remain stable. Apparently, for these the entropy loss of forming β-rolls and β-sheets is compensated for in the free-energy gain due to the hydrogen-bonding and hydrophobic interactions. We also find that the middle monomers in the trimers and tetramers are conformationally much more stable than the ones on the top and the bottom. Interestingly, the latter are more stable on the tetramer than on the trimer, suggesting that as the number of monomers increases protein-protein interactions cooperatively stabilize the assembly. According to our simulations, the β-roll and β-sheet aggregates must be approximately equally stable.
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Affiliation(s)
- Jamoliddin Razzokov
- Department of Chemistry, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium. Faculteit Technische Natuurkunde, Technische Universiteit Eindhoven, Postbus 513, 5600 MB Eindhoven, Netherlands
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9
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Chan HCS, Wang J, Palczewski K, Filipek S, Vogel H, Liu ZJ, Yuan S. Exploring a new ligand binding site of G protein-coupled receptors. Chem Sci 2018; 9:6480-6489. [PMID: 30310578 PMCID: PMC6115637 DOI: 10.1039/c8sc01680a] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 07/12/2018] [Indexed: 01/08/2023] Open
Abstract
Identifying a target ligand binding site is an important step for structure-based rational drug design as shown here for G protein-coupled receptors (GPCRs), which are among the most popular drug targets. We applied long-time scale molecular dynamics simulations, coupled with mutagenesis studies, to two prototypical GPCRs, the M3 and M4 muscarinic acetylcholine receptors. Our results indicate that unlike synthetic antagonists, which bind to the classic orthosteric site, the endogenous agonist acetylcholine is able to diffuse into a much deeper binding pocket. We also discovered that the most recently resolved crystal structure of the LTB4 receptor comprised a bound inverse agonist, which extended its benzamidine moiety to the same binding pocket discovered in this work. Analysis on all resolved GPCR crystal structures indicated that this new pocket could exist in most receptors. Our findings provide new opportunities for GPCR drug discovery.
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Affiliation(s)
| | - Jingjing Wang
- iHuman Institute , ShanghaiTech University , China .
| | | | - Slawomir Filipek
- Faculty of Chemistry , Biological and Chemical Research Centre , University of Warsaw , Poland
| | - Horst Vogel
- Institute of Chemical Sciences and Engineering , Ecole Polytechnique Fédérale de Lausanne (EPFL) , Switzerland . ;
| | - Zhi-Jie Liu
- iHuman Institute , ShanghaiTech University , China .
| | - Shuguang Yuan
- Institute of Chemical Sciences and Engineering , Ecole Polytechnique Fédérale de Lausanne (EPFL) , Switzerland . ;
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10
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A model for hydrophobic protrusions on peripheral membrane proteins. PLoS Comput Biol 2018; 14:e1006325. [PMID: 30048443 PMCID: PMC6080788 DOI: 10.1371/journal.pcbi.1006325] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2017] [Revised: 08/07/2018] [Accepted: 06/24/2018] [Indexed: 11/19/2022] Open
Abstract
With remarkable spatial and temporal specificities, peripheral membrane proteins bind to biological membranes. They do this without compromising solubility of the protein, and their binding sites are not easily distinguished. Prototypical peripheral membrane binding sites display a combination of patches of basic and hydrophobic amino acids that are also frequently present on other protein surfaces. The purpose of this contribution is to identify simple but essential components for membrane binding, through structural criteria that distinguish exposed hydrophobes at membrane binding sites from those that are frequently found on any protein surface. We formulate the concepts of protruding hydrophobes and co-insertability and have analysed more than 300 families of proteins that are classified as peripheral membrane binders. We find that this structural motif strongly discriminates the surfaces of membrane-binding and non-binding proteins. Our model constitutes a novel formulation of a structural pattern for membrane recognition and emphasizes the importance of subtle structural properties of hydrophobic membrane binding sites. Peripheral membrane proteins bind cellular membranes transiently, and are otherwise soluble proteins. As the interaction between proteins and membranes happens at cellular interfaces they are naturally involved in important interfacial processes such as recognition, signaling and trafficking. Commonly their binding sites are also soluble, and their binding mechanisms poorly understood. This complicates the elaboration of conceptual and quantitative models for peripheral membrane binding and makes binding site prediction difficult. It is therefore of great interest to discover traits that are common between these binding sites and that distinguishes them from other protein surfaces. In this work we identify simple and general structural features that facilitate membrane recognition by soluble proteins. We show that these motifs are highly over-represented on peripheral membrane proteins.
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11
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Dutagaci B, Feig M. Determination of Hydrophobic Lengths of Membrane Proteins with the HDGB Implicit Membrane Model. J Chem Inf Model 2017; 57:3032-3042. [PMID: 29155578 DOI: 10.1021/acs.jcim.7b00510] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A protocol for predicting the hydrophobic length of membrane proteins using the heterogeneous dielectric generalized Born (HDGB) implicit membrane model is presented. The method involves optimal positioning in the membrane and identification of lipid-facing and inward-facing residues, followed by energy optimization of the implicit membrane model to obtain the hydrophobic length from the optimal membrane width. The latest HDGB version 3 (HDGBv3) and HDGB van der Waals (HDGBvdW) models were applied to a test set containing 15 proteins (seven β-barrel and eight α-helical proteins), for which matching membrane widths are available from experiment, and an additional set contains ten α-helical and ten β-barrel proteins without any experimental data. The results with the HDGB model compare favorably with predictions from methods used in the Orientations of Proteins in Membranes (OPM) and Protein Data Bank of Transmembrane Proteins (PDB-TM) databases.
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Affiliation(s)
- Bercem Dutagaci
- Department of Biochemistry and Molecular Biology, Michigan State University , 603 Wilson Road, Room BCH, 218, East Lansing, Michigan 48824, United States
| | - Michael Feig
- Department of Biochemistry and Molecular Biology, Michigan State University , 603 Wilson Road, Room BCH, 218, East Lansing, Michigan 48824, United States
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12
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Interactions stabilizing the C-terminal helix of human phospholipid scramblase 1 in lipid bilayers: A computational study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1200-1210. [DOI: 10.1016/j.bbamem.2017.03.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 03/09/2017] [Accepted: 03/29/2017] [Indexed: 12/19/2022]
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13
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TMDOCK: An Energy-Based Method for Modeling α-Helical Dimers in Membranes. J Mol Biol 2017; 429:390-398. [DOI: 10.1016/j.jmb.2016.09.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 08/26/2016] [Accepted: 09/02/2016] [Indexed: 11/22/2022]
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14
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Chan HCS, Filipek S, Yuan S. The Principles of Ligand Specificity on beta-2-adrenergic receptor. Sci Rep 2016; 6:34736. [PMID: 27703221 PMCID: PMC5050457 DOI: 10.1038/srep34736] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 09/15/2016] [Indexed: 12/11/2022] Open
Abstract
G protein-coupled receptors are recognized as one of the largest families of membrane proteins. Despite sharing a characteristic seven-transmembrane topology, G protein-coupled receptors regulate a wide range of cellular signaling pathways in response to various physical and chemical stimuli, and prevail as an important target for drug discovery. Notably, the recent progress in crystallographic methods led to a breakthrough in elucidating the structures of membrane proteins. The structures of β2-adrenergic receptor bound with a variety of ligands provide atomic details of the binding modes of agonists, antagonists and inverse agonists. In this study, we selected four representative molecules from each functional class of ligands and investigated their impacts on β2-adrenergic receptor through a total of 12 × 100 ns molecular dynamics simulations. From the obtained trajectories, we generated molecular fingerprints exemplifying propensities of protein-ligand interactions. For each functional class of compounds, we characterized and compared the fluctuation of the protein backbone, the volumes in the intracellular pockets, the water densities in the receptors, the domain interaction networks as well as the movements of transmembrane helices. We discovered that each class of ligands exhibits a distinct mode of interactions with mainly TM5 and TM6, altering the shape and eventually the state of the receptor. Our findings provide insightful prospective into GPCR targeted structure-based drug discoveries.
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Affiliation(s)
- H C Stephen Chan
- Faculty of Life Sciences, University of Bradford, Bradford, West Yorkshire, BD7 1DP, United Kingdom
| | - Slawomir Filipek
- Laboratory of Biomodeling, Faculty of Chemistry &Biological and Chemical Research Centre, University of Warsaw, ul. Pasteura 1, Warsaw 02-093, Poland
| | - Shuguang Yuan
- Laboratory of Physical Chemistry of Polymers and Membranes, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH B3 495 (Bâtiment CH) Station 6, Lausanne CH-1015, Switzerland
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15
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Yuan S, Palczewski K, Peng Q, Kolinski M, Vogel H, Filipek S. The Mechanism of Ligand-Induced Activation or Inhibition of μ- and κ-Opioid Receptors. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201501742] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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16
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Yuan S, Palczewski K, Peng Q, Kolinski M, Vogel H, Filipek S. The mechanism of ligand-induced activation or inhibition of μ- and κ-opioid receptors. Angew Chem Int Ed Engl 2015; 54:7560-3. [PMID: 25968837 DOI: 10.1002/anie.201501742] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 03/30/2015] [Indexed: 12/19/2022]
Abstract
G-protein-coupled receptors (GPCRs) are important targets for treating severe diseases. However why certain molecules act as activators whereas others, with similar structures, block GPCR activation, is poorly understood since the same molecule can activate one receptor subtype while blocking another closely related receptor. To shed light on these central questions, we used all-atom, long-time-scale molecular dynamics simulations on the κ-opioid and μ-opioid receptors (κOR and μOR). We found that water molecules penetrating into the receptor interior mediate the activating versus blocking effects of a particular ligand-receptor interaction. Both the size and the flexibility of the bound ligand regulated water influx into the receptor. The solvent-accessible inner surface area was found to be a parameter that can help predict the function of the bound ligand.
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Affiliation(s)
- Shuguang Yuan
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Institute of Chemical Sciences and Engineering, Lausanne (Switzerland).
| | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland (USA)
| | - Qian Peng
- Department of Chemistry, University of Oxford (UK)
| | - Michal Kolinski
- Bioinformatics Laboratory, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw (Poland)
| | - Horst Vogel
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Institute of Chemical Sciences and Engineering, Lausanne (Switzerland).
| | - Slawomir Filipek
- Laboratory of Biomodeling, Faculty of Chemistry & Biological and Chemical Research Centre, University of Warsaw, Warsaw (Poland).
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Yuan S, Hu Z, Filipek S, Vogel H. W2466.48Opens a Gate for a Continuous Intrinsic Water Pathway during Activation of the Adenosine A2AReceptor. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201409679] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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18
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Yuan S, Hu Z, Filipek S, Vogel H. W246(6.48) opens a gate for a continuous intrinsic water pathway during activation of the adenosine A2A receptor. Angew Chem Int Ed Engl 2014; 54:556-9. [PMID: 25403323 DOI: 10.1002/anie.201409679] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Indexed: 01/21/2023]
Abstract
The question how G-protein-coupled receptors transduce an extracellular signal by a sequence of transmembrane conformational transitions into an intracellular response remains to be solved at molecular detail. Herein, we use molecular dynamics simulations to reveal distinct conformational transitions of the adenosine A2A receptor, and we found that the conserved W246(6.48) residue in transmembrane helix TM6 performs a key rotamer toggle switch. Agonist binding induces the sidechain of W246(6.48) to fluctuate between two distinct conformations enabling the diffusion of water molecules from the bulk into the center of the receptor. After passing the W246(6.48) gate, the internal water molecules induce another conserved residue, Y288(7.53), to switch to a distinct rotamer conformation establishing a continuous transmembrane water pathway. Further, structural changes of TM6 and TM7 induce local structural changes of the adjacent lipid bilayer.
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Affiliation(s)
- Shuguang Yuan
- Laboratory of Physical Chemistry of Polymers and Membranes, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne (Switzerland).
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19
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Teixeira R, Barbosa L, Kabeshov M, Maltha C, Corrêa R, Doriguetto A. NMR and X-ray structural characterization and conformational aspects of fluorinated (5Z)-3-benzil-5-arylidenofuran-2(5H)-ones. J Mol Struct 2014. [DOI: 10.1016/j.molstruc.2014.05.045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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20
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Natesan S, Lukacova V, Peng M, Subramaniam R, Lynch S, Wang Z, Tandlich R, Balaz S. Structure-based prediction of drug distribution across the headgroup and core strata of a phospholipid bilayer using surrogate phases. Mol Pharm 2014; 11:3577-95. [PMID: 25179490 PMCID: PMC4186683 DOI: 10.1021/mp5003366] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
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Solvation of drugs in the core (C)
and headgroup (H) strata of
phospholipid bilayers affects their physiological transport rates
and accumulation. These characteristics, especially a complete drug
distribution profile across the bilayer strata, are tedious to obtain
experimentally, to the point that even simplified preferred locations
are only available for a few dozen compounds. Recently, we showed
that the partition coefficient (P) values in the
system of hydrated diacetyl phosphatidylcholine (DAcPC) and n-hexadecane (C16), as surrogates of the H- and C-strata
of the bilayer composed of the most abundant mammalian phospholipid,
PC, agree well with the preferred bilayer location of compounds. High P values are typical for lipophiles accumulating in the
core, and low P values are characteristic of cephalophiles
preferring the headgroups. This simple pattern does not hold for most
compounds, which usually have more even distribution and may also
accumulate at the H/C interface. To model complete distribution, the
correlates of solvation energies are needed for each drug state in
the bilayer: (1) for the H-stratum it is the DAcPC/W P value, calculated as the ratio of the C16/W and C16/DAcPC (W for
water) P values; (2) for the C-stratum, the C16/W P value; (3) for the H/C interface, the P values for all plausible molecular poses are characterized using
the fragment DAcPC/W and C16/W solvation parameters for the parts
of the molecule embedded in the H- and C-strata, respectively. The
correlates, each scaled by two Collander coefficients, were used in
a nonlinear, mass-balance based model of intrabilayer distribution,
which was applied to the easily measurable overall P values of compounds in the DMPC (M = myristoyl) bilayers and monolayers
as the dependent variables. The calibrated model for 107 neutral compounds
explains 94% of experimental variance, achieves similar cross-validation
levels, and agrees well with the nontrivial, experimentally determined
bilayer locations for 27 compounds. The resulting structure-based
prediction system for intrabilayer distribution will facilitate more
realistic modeling of passive transport and drug interactions with
those integral membrane proteins, which have the binding sites located
in the bilayer, such as some enzymes, influx and efflux transporters,
and receptors. If only overall bilayer accumulation is of interest,
the 1-octanol/W P values suffice to model the studied
set.
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Affiliation(s)
- Senthil Natesan
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences , Vermont Campus, Colchester, Vermont 05446, United States
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21
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Activation of G-protein-coupled receptors correlates with the formation of a continuous internal water pathway. Nat Commun 2014; 5:4733. [PMID: 25203160 DOI: 10.1038/ncomms5733] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 07/17/2014] [Indexed: 12/19/2022] Open
Abstract
Recent crystal structures of G-protein-coupled receptors (GPCRs) have revealed ordered internal water molecules, raising questions about the functional role of those waters for receptor activation that could not be answered by the static structures. Here, we used molecular dynamics simulations to monitor--at atomic and high temporal resolution--conformational changes of central importance for the activation of three prototypical GPCRs with known crystal structures: the adenosine A2A receptor, the β2-adrenergic receptor and rhodopsin. Our simulations reveal that a hydrophobic layer of amino acid residues next to the characteristic NPxxY motif forms a gate that opens to form a continuous water channel only upon receptor activation. The highly conserved tyrosine residue Y(7.53) undergoes transitions between three distinct conformations representative of inactive, G-protein activated and GPCR metastates. Additional analysis of the available GPCR crystal structures reveals general principles governing the functional roles of internal waters in GPCRs.
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22
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ProBLM web server: protein and membrane placement and orientation package. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2014; 2014:838259. [PMID: 25126110 PMCID: PMC4122144 DOI: 10.1155/2014/838259] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 06/28/2014] [Accepted: 07/01/2014] [Indexed: 01/08/2023]
Abstract
The 3D structures of membrane proteins are typically determined without the presence of a lipid bilayer. For the purpose of studying the role of membranes on the wild type characteristics of the corresponding protein, determining the position and orientation of transmembrane proteins within a membrane environment is highly desirable. Here we report a geometry-based approach to automatically insert a membrane protein with a known 3D structure into pregenerated lipid bilayer membranes with various dimensions and lipid compositions or into a pseudomembrane. The pseudomembrane is built using the Protein Nano-Object Integrator which generates a parallelepiped of user-specified dimensions made up of pseudoatoms. The pseudomembrane allows for modeling the desolvation effects while avoiding plausible errors associated with wrongly assigned protein-lipid contacts. The method is implemented into a web server, the ProBLM server, which is freely available to the biophysical community. The web server allows the user to upload a protein coordinate file and any missing residues or heavy atoms are regenerated. ProBLM then creates a combined protein-membrane complex from the given membrane protein and bilayer lipid membrane or pseudomembrane. The user is given an option to manually refine the model by manipulating the position and orientation of the protein with respect to the membrane.
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23
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Pogozheva ID, Mosberg HI, Lomize AL. Life at the border: adaptation of proteins to anisotropic membrane environment. Protein Sci 2014; 23:1165-96. [PMID: 24947665 DOI: 10.1002/pro.2508] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 06/17/2014] [Accepted: 06/18/2014] [Indexed: 12/25/2022]
Abstract
This review discusses main features of transmembrane (TM) proteins which distinguish them from water-soluble proteins and allow their adaptation to the anisotropic membrane environment. We overview the structural limitations on membrane protein architecture, spatial arrangement of proteins in membranes and their intrinsic hydrophobic thickness, co-translational and post-translational folding and insertion into lipid bilayers, topogenesis, high propensity to form oligomers, and large-scale conformational transitions during membrane insertion and transport function. Special attention is paid to the polarity of TM protein surfaces described by profiles of dipolarity/polarizability and hydrogen-bonding capacity parameters that match polarity of the lipid environment. Analysis of distributions of Trp resides on surfaces of TM proteins from different biological membranes indicates that interfacial membrane regions with preferential accumulation of Trp indole rings correspond to the outer part of the lipid acyl chain region-between double bonds and carbonyl groups of lipids. These "midpolar" regions are not always symmetric in proteins from natural membranes. We also examined the hydrophobic effect that drives insertion of proteins into lipid bilayer and different free energy contributions to TM protein stability, including attractive van der Waals forces and hydrogen bonds, side-chain conformational entropy, the hydrophobic mismatch, membrane deformations, and specific protein-lipid binding.
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Affiliation(s)
- Irina D Pogozheva
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, 48109-1065
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24
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25
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Poole CF, Ariyasena TC, Lenca N. Estimation of the environmental properties of compounds from chromatographic measurements and the solvation parameter model. J Chromatogr A 2013; 1317:85-104. [DOI: 10.1016/j.chroma.2013.05.045] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 04/15/2013] [Accepted: 05/20/2013] [Indexed: 11/29/2022]
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26
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Lukacova V, Natesan S, Peng M, Tandlich R, Wang Z, Lynch S, Subramaniam R, Balaz S. Structural determinants of drug partitioning in surrogates of phosphatidylcholine bilayer strata. Mol Pharm 2013; 10:3684-96. [PMID: 23964749 PMCID: PMC3884577 DOI: 10.1021/mp400204y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The knowledge of drug concentrations in bilayer headgroups, core, and at the interface between them is a prerequisite for quantitative modeling of drug interactions with many membrane-bound transporters, metabolizing enzymes and receptors, which have the binding sites located in the bilayer. This knowledge also helps understand the rates of trans-bilayer transport because balanced interactions of drugs with the bilayer strata lead to high rates, while excessive affinities for any stratum cause a slowdown. Experimental determination of bilayer location is so tedious and costly that the data are only available for some fifty compounds. To extrapolate these valuable results to more compounds at a higher throughput, surrogate phases have been used to obtain correlates of the drug affinities for individual strata. We introduced a novel system, consisting of a diacetyl phosphatidylcholine (DAcPC) solution with the water content of the fluid bilayer as the headgroup surrogate and n-hexadecane (C16) representing the core. The C16/DAcPC partition coefficients were measured for 113 selected compounds, containing structural fragments that are frequently occurring in approved drugs. The data were deconvoluted into the ClogP-based fragment solvation characteristics and processed using a solvatochromic correlation. Increased H-bond donor ability and excess molar refractivity of compounds promote solvation in the DAcPC phase as compared to bulk water, contrary to H-bond acceptor ability, dipolarity/polarizability, and volume. The results show that aromates have more balanced distribution in bilayer strata, and thus faster trans-bilayer transport, than similar alkanes. This observation is in accordance with the frequent occurrence of aromatic rings in approved drugs and with the role of rigidity of drug molecules in promoting intestinal absorption. Bilayer locations, predicted using the C16/DAcPC system, are in excellent agreement with available experimental data, in contrast to other surrogate systems.
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Affiliation(s)
- Viera Lukacova
- College of Pharmacy, North Dakota State University, Fargo, North Dakota 58102, United States
| | - Senthil Natesan
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Vermont Campus, Colchester, Vermont 05446, United States
| | - Ming Peng
- College of Pharmacy, North Dakota State University, Fargo, North Dakota 58102, United States
| | - Roman Tandlich
- Division of Pharmaceutical Chemistry, Faculty of Pharmacy, Rhodes University, Grahamstown, 6140 South Africa
| | - Zhanbin Wang
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Vermont Campus, Colchester, Vermont 05446, United States
| | - Sandra Lynch
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Vermont Campus, Colchester, Vermont 05446, United States
| | - Rajesh Subramaniam
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Vermont Campus, Colchester, Vermont 05446, United States
| | - Stefan Balaz
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Vermont Campus, Colchester, Vermont 05446, United States
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27
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Pogozheva ID, Tristram-Nagle S, Mosberg HI, Lomize AL. Structural adaptations of proteins to different biological membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2592-608. [PMID: 23811361 DOI: 10.1016/j.bbamem.2013.06.023] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 06/04/2013] [Accepted: 06/19/2013] [Indexed: 02/06/2023]
Abstract
To gain insight into adaptations of proteins to their membranes, intrinsic hydrophobic thicknesses, distributions of different chemical groups and profiles of hydrogen-bonding capacities (α and β) and the dipolarity/polarizability parameter (π*) were calculated for lipid-facing surfaces of 460 integral α-helical, β-barrel and peripheral proteins from eight types of biomembranes. For comparison, polarity profiles were also calculated for ten artificial lipid bilayers that have been previously studied by neutron and X-ray scattering. Estimated hydrophobic thicknesses are 30-31Å for proteins from endoplasmic reticulum, thylakoid, and various bacterial plasma membranes, but differ for proteins from outer bacterial, inner mitochondrial and eukaryotic plasma membranes (23.9, 28.6 and 33.5Å, respectively). Protein and lipid polarity parameters abruptly change in the lipid carbonyl zone that matches the calculated hydrophobic boundaries. Maxima of positively charged protein groups correspond to the location of lipid phosphates at 20-22Å distances from the membrane center. Locations of Tyr atoms coincide with hydrophobic boundaries, while distributions maxima of Trp rings are shifted by 3-4Å toward the membrane center. Distributions of Trp atoms indicate the presence of two 5-8Å-wide midpolar regions with intermediate π* values within the hydrocarbon core, whose size and symmetry depend on the lipid composition of membrane leaflets. Midpolar regions are especially asymmetric in outer bacterial membranes and cell membranes of mesophilic but not hyperthermophilic archaebacteria, indicating the larger width of the central nonpolar region in the later case. In artificial lipid bilayers, midpolar regions are observed up to the level of acyl chain double bonds.
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Affiliation(s)
- Irina D Pogozheva
- College of Pharmacy, Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI 48109-1065, USA.
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28
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Madhongsa K, Pasan S, Phophetleb O, Nasompag S, Thammasirirak S, Daduang S, Taweechaisupapong S, Lomize AL, Patramanon R. Antimicrobial action of the cyclic peptide bactenecin on Burkholderia pseudomallei correlates with efficient membrane permeabilization. PLoS Negl Trop Dis 2013; 7:e2267. [PMID: 23785532 PMCID: PMC3681726 DOI: 10.1371/journal.pntd.0002267] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 05/01/2013] [Indexed: 01/05/2023] Open
Abstract
Burkholderia pseudomallei is a category B agent that causes Melioidosis, an acute and chronic disease with septicemia. The current treatment regimen is a heavy dose of antibiotics such as ceftazidime (CAZ); however, the risk of a relapse is possible. Peptide antibiotics are an alternative to classical antibiotics as they exhibit rapid action and are less likely to result in the development of resistance. The aim of this study was to determine the bactericidal activity against B. pseudomallei and examine the membrane disrupting abilities of the potent antimicrobial peptides: bactenecin, RTA3, BMAP-18 and CA-MA. All peptides exhibited >97% bactericidal activity at 20 µM, with bactenecin having slightly higher activity. Long term time-kill assays revealed a complete inhibition of cell growth at 50 µM bactenecin and CA-MA. All peptides inhibited biofilm formation comparable to CAZ, but exhibited faster kinetics (within 1 h). Bactenecin exhibited stronger binding to LPS and induced perturbation of the inner membrane of live cells. Interaction of bactenecin with model membranes resulted in changes in membrane fluidity and permeability, leading to leakage of dye across the membrane at levels two-fold greater than that of other peptides. Modeling of peptide binding on the membrane showed stable and deep insertion of bactenecin into the membrane (up to 9 Å). We propose that bactenecin is able to form dimers or large β-sheet structures in a concentration dependent manner and subsequently rapidly permeabilize the membrane, leading to cytosolic leakage and cell death in a shorter period of time compared to CAZ. Bactenecin might be considered as a potent antimicrobial agent for use against B. pseudomallei. Burkholderia pseudomallei is a category B agent that causes Melioidosis, an acute and chronic disease with septicemia. The current treatment regimen is a heavy dose of antibiotics such as ceftazidime (CAZ), however, the risk of a relapse is possible. In this study we demonstrate that bactenecin, CA-MA, RTA3 and BMAP-18 are able to inhibit the growth and biofilm formation of B. pseudomallei. The strong bactericidal activity of bactenecin is attributed to its greater ability to permeabilize the membrane. Computational modeling of these peptide-membrane interactions provide support for a model in which bactenecin is able to penetrate the membrane most effectively due to its cyclical structure. The peptide, bactenecin has the potential to act as a highly effective alternative to CAZ, or as a combination therapy with CAZ in the treatment of melioidosis. Furthermore, understanding the mechanism of bactenecin may help us better design more effective peptides therapeutics of choice for melioidosis.
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Affiliation(s)
- Kanjana Madhongsa
- Protein and Proteomics Research Center for Commercial and Industrial Purposes (ProCCI), Khon Kaen University, Khon Kaen, Thailand
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
| | - Supaluk Pasan
- Protein and Proteomics Research Center for Commercial and Industrial Purposes (ProCCI), Khon Kaen University, Khon Kaen, Thailand
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
| | - Onanong Phophetleb
- Protein and Proteomics Research Center for Commercial and Industrial Purposes (ProCCI), Khon Kaen University, Khon Kaen, Thailand
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
| | - Sawinee Nasompag
- Protein and Proteomics Research Center for Commercial and Industrial Purposes (ProCCI), Khon Kaen University, Khon Kaen, Thailand
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
| | - Sompong Thammasirirak
- Protein and Proteomics Research Center for Commercial and Industrial Purposes (ProCCI), Khon Kaen University, Khon Kaen, Thailand
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
| | - Sakda Daduang
- Protein and Proteomics Research Center for Commercial and Industrial Purposes (ProCCI), Khon Kaen University, Khon Kaen, Thailand
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
| | - Suwimol Taweechaisupapong
- Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand
- Biofilm Research Group, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
| | - Andrei L. Lomize
- College of Pharmacy, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Rina Patramanon
- Protein and Proteomics Research Center for Commercial and Industrial Purposes (ProCCI), Khon Kaen University, Khon Kaen, Thailand
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
- * E-mail:
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29
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Yuzlenko O, Lazaridis T. Membrane protein native state discrimination by implicit membrane models. J Comput Chem 2013; 34:731-8. [PMID: 23224861 PMCID: PMC3584241 DOI: 10.1002/jcc.23189] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 10/16/2012] [Accepted: 10/28/2012] [Indexed: 02/01/2023]
Abstract
Four implicit membrane models [IMM1, generalized Born (GB)-surface area-implicit membrane (GBSAIM), GB with a simple switching (GBSW), and heterogeneous dielectric GB (HDGB)] were tested for their ability to discriminate the native conformation of five membrane proteins from 450 decoys generated by the Rosetta-Membrane program. The energy ranking of the native state and Z-scores were used to assess the performance of the models. The effect of membrane thickness was examined and was found to be substantial. Quite satisfactory discrimination was achieved with the all-atom IMM1 and GBSW models at 25.4 Å thickness and with the HDGB model at 28.5 Å thickness. The energy components by themselves were not discriminative. Both van der Waals and electrostatic interactions contributed to native state discrimination, to a different extent in each model. Computational efficiency of the models decreased in the order: extended-atom IMM1 > all-atom IMM1 > GBSAIM > GBSW > HDGB. These results encourage the further development and use of implicit membrane models for membrane protein structure prediction.
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Affiliation(s)
- Olga Yuzlenko
- Department of Chemistry, City College of the City University of New York, 160 Convent Avenue, New York, New York 10031, USA
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30
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Lomize AL, Pogozheva ID. Solvation models and computational prediction of orientations of peptides and proteins in membranes. Methods Mol Biol 2013; 1063:125-42. [PMID: 23975775 DOI: 10.1007/978-1-62703-583-5_7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Membrane-associated peptides and proteins function in the highly heterogeneous environment of the lipid bilayer whose physico-chemical properties change non-monotonically along the bilayer normal. To simulate insertion of peptides and proteins into membranes and correctly reproduce the energetics of this process, an adequate solvation model and physically realistic representation of the lipid bilayer should be employed. We present a brief overview of the existing solvation models and their application for prediction of binding affinities and orientations of proteins in membranes. Particular emphasis is placed on the recently proposed PPM method, the corresponding web server, and the OPM database that were designed for positioning in membranes of integral and peripheral proteins with known three-dimensional structures.
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Affiliation(s)
- Andrei L Lomize
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA
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31
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Membrane topology of the colicin E1 channel using genetically encoded fluorescence. Biochemistry 2011; 50:4830-42. [PMID: 21528912 DOI: 10.1021/bi101934e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The membrane topology of the colicin E1 channel domain was studied by fluorescence resonance energy transfer (FRET). The FRET involved a genetically encoded fluorescent amino acid (coumarin) as the donor and a selectively labeled cysteine residue tethered with DABMI (4-(dimethylamino)phenylazophenyl-4'-maleimide) as the FRET acceptor. The fluorescent coumarin residue was incorporated into the protein via an orthogonal tRNA/aminoacyl-tRNA synthetase pair that allowed selective incorporation into any site within the colicin channel domain. Each variant harbored a stop (TAG) mutation for coumarin incorporation and a cysteine (TGT) mutation for DABMI attachment. Six interhelical distances within helices 1-6 were determined using FRET analysis for both the soluble and membrane-bound states. The FRET data showed large changes in the interhelical distances among helices 3-6 upon membrane association providing new insight into the membrane-bound structure of the channel domain. In general, the coumarin-DABMI FRET interhelical efficiencies decreased upon membrane binding, building upon the umbrella model for the colicin channel. A tentative model for the closed state of the channel domain was developed based on current and previously published FRET data. The model suggests circular arrangement of helices 1-7 in a clockwise direction from the extracellular side and membrane interfacial association of helices 1, 6, 7, and 10 around the central transmembrane hairpin formed by helices 8 and 9.
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