1
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Jeican II, Matei H, Istrate A, Mironescu E, Bâlici Ş. Changes observed in erythrocyte cells exposed to an alternating current. ACTA ACUST UNITED AC 2017; 90:154-160. [PMID: 28559698 PMCID: PMC5433566 DOI: 10.15386/cjmed-696] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 10/17/2016] [Accepted: 10/31/2016] [Indexed: 11/23/2022]
Abstract
Background and aims Appliance of electric pulses induces red blood cells (RBCs) membrane poration, membrane aminophospholipid perturbation and alteration of the normal flip-flop process, resulting in various shape changes of the RBCs. We studied morphological and water permeability changes of RBCs bombarded with electrons in an alternating current circuit. Methods We used three venous blood samples of 100 mL and an alternating current device. The harvested blood was divided into four experimental sets to be used for various exposure times: 0 hours (control RBCs), 0.5h, 3h and 6h (electric-stimulated RBCs). Following the electric current each of the four sets were further divided into three samples: one for the assessment of the echinocytes/RBCs ratio, another for the electron microscopy study of ultrastructural changes induced by the alternating electrical current and a larger third one for determining water permeability of RCBs by 1H-NMR spectroscopy and morphological measurements. Results There is a small but statistically significant effect of the RBC exposure to alternating electric current on cell diameters. Exposure to electric current is positively and strongly correlated with the percentage of echinocytes in a duration-dependent manner. There is a strong and statistically significant correlation between electric current exposure and permeability to water as measured by 1H-NMR spectroscopy. Conclusion Following interactions between electric current and RBC membrane, certain modifications were observed in the erythrocyte structure. We attribute the increased cell size to a higher permeability to water and a decreased tonicity. This leads to the transformation of the RBCs into echinocytes.
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Affiliation(s)
- Ionut Isaia Jeican
- Department of Cell and Molecular Biology, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Horea Matei
- Department of Cell and Molecular Biology, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Alexandru Istrate
- Department of Cell and Molecular Biology, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Eugen Mironescu
- Department of Cell and Molecular Biology, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Ştefana Bâlici
- Department of Cell and Molecular Biology, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
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Hassan SA. Computational Study of the Forces Driving Aggregation of Ultrasmall Nanoparticles in Biological Fluids. ACS NANO 2017; 11:4145-4154. [PMID: 28314103 PMCID: PMC5534356 DOI: 10.1021/acsnano.7b00981] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Nanoparticle (NP) aggregation can lead to prolonged retention in tissues or embolism, among other adverse effects. Successful use in biomedicine thus requires the capability to make NPs with limited aggregative potential. Rational design is presently a challenge due to incomplete knowledge of their interactions in biofluids. Recently, ultrasmall gold NPs passivated with endogenous antioxidant glutathione have shown promise for use in vivo. Computer simulations are here conducted to identify the forces underlying aggregation (or lack thereof) of these NPs in a cell culture. Electrostatic interactions are insufficient to induce association, but the van der Waals forces exerted by cations, anions, and net-neutral polar species can promote the formation of stable dimers. The entropic effects of depletion are negligible, but the combined effect of depletion and macromolecular crowding at physiological concentrations can stabilize aggregates containing just a few NPs. Interparticle interactions are controlled by modest changes in both the structure and dynamic of the interfacial liquid. The molecular origin of these effects and their dependence on NP size are described. The liquid is shown to be highly structured, with large and long-lived hydrogen-bonded water clusters developing often in the interparticle space; their potential role as transient, long-range proton wires connecting and enveloping neighboring NPs is discussed. The basis for a parsimonious theory of ultrasmall NPs in complex fluids is established.
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Affiliation(s)
- Sergio A. Hassan
- Center for Molecular Modeling, OIR/CIT, National Institutes of Health, U.S. DHHS, Bethesda, Maryland 20892, United States
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3
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Mazzuca JW, Schultz CP. Quantum Mechanical Enhancement of Rate Constants and Kinetic Isotope Effects for Water-Mediated Proton Transfer in a Model Biological System. J Phys Chem A 2017; 121:819-826. [DOI: 10.1021/acs.jpca.6b10337] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- James W. Mazzuca
- Chemistry Department, Alma College, Alma, Michigan 48801, United States
| | - Chase P. Schultz
- Chemistry Department, Alma College, Alma, Michigan 48801, United States
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Xu H, Cheng J, Li Q, Li W. Some measures for making a traditional halogen bond be chlorine-shared or ion-pair one in FCl•NH3 complex. Mol Phys 2016. [DOI: 10.1080/00268976.2016.1255798] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Huili Xu
- The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai, People's Republic of China
| | - Jianbo Cheng
- The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai, People's Republic of China
| | - Qingzhong Li
- The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai, People's Republic of China
| | - Wenzuo Li
- The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai, People's Republic of China
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Kayal A, Chandra A. Wetting and dewetting of narrow hydrophobic channels by orthogonal electric fields: Structure, free energy, and dynamics for different water models. J Chem Phys 2015; 143:224708. [DOI: 10.1063/1.4936939] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Abhijit Kayal
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
| | - Amalendu Chandra
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
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DeCoursey TE, Hosler J. Philosophy of voltage-gated proton channels. J R Soc Interface 2014; 11:20130799. [PMID: 24352668 PMCID: PMC3899857 DOI: 10.1098/rsif.2013.0799] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 11/22/2013] [Indexed: 02/02/2023] Open
Abstract
In this review, voltage-gated proton channels are considered from a mainly teleological perspective. Why do proton channels exist? What good are they? Why did they go to such lengths to develop several unique hallmark properties such as extreme selectivity and ΔpH-dependent gating? Why is their current so minuscule? How do they manage to be so selective? What is the basis for our belief that they conduct H(+) and not OH(-)? Why do they exist in many species as dimers when the monomeric form seems to work quite well? It is hoped that pondering these questions will provide an introduction to these channels and a way to logically organize their peculiar properties as well as to understand how they are able to carry out some of their better-established biological functions.
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Affiliation(s)
- Thomas E. DeCoursey
- Department of Molecular Biophysics and Physiology, Rush University, 1750 West Harrison, Chicago, IL 60612, USA
| | - Jonathan Hosler
- Department of Biochemistry, University of Mississippi Medical Center, Jackson, MS 39216, USA
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7
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Lee SH, Rasaiah JC. Proton transfer and the diffusion of H+ and OH− ions along water wires. J Chem Phys 2013; 139:124507. [DOI: 10.1063/1.4821764] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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8
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Proton transfer reactions in carbon nanotubes endohedrally functionalized with selected polar amino acid sidechains. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2012.06.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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9
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Bankura A, Chandra A. Hydroxide ion can move faster than an excess proton through one-dimensional water chains in hydrophobic narrow pores. J Phys Chem B 2012; 116:9744-57. [PMID: 22793519 DOI: 10.1021/jp301466e] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Carbon nanotubes (CNT) are known to provide a hydrophobic, confined environment for water where its structure and dynamics can be very different from those of bulk water. In particular, narrow CNTs of the type (6,6) allow only a single one-dimensional (1D) chain of water molecules inside them, thus providing an idealized scenario to study motion in 1D along water chains. In the present study, we have investigated structural and dynamic behavior of water and also of an excess proton and hydroxide ion in water-filled narrow CNTs by means of ab initio molecular dynamics and combined quantum-classical simulations. The main focus of the present work is on the molecular mechanism and kinetics of hydronium and hydroxide ion migration along 1D water chains of different lengths in confinement. It is found that the hydrogen-bonded structures of water and the excess proton and hydroxide ion in CNTs can be very different from those in bulk, and these altered solvation structures play critical roles in determining the proton-transfer (PT) rates along water chains. For the present 1D chain systems, the hydroxide ion is found to migrate at a slightly faster rate than the excess proton, unlike their relative mobilities in bulk water. This faster migration of the hydroxide ion is found not only in CNTs with periodicity along the tube axis but also in isolated CNTs where the excess proton and the hydroxide ion are allowed to move under the influence of an electric field of an oppositely charged ion. The roles of rotational jumps and hydrogen-bond fluctuations in the PT events are discussed. In addition, the significance of hydrogen-bonding defects on the dynamics of an excess proton and hydroxide ion is also discussed for varying chain lengths.
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Affiliation(s)
- Arindam Bankura
- Department of Chemistry, Indian Institute of Technology, Kanpur, India 208016
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10
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Li X, Shi Y, Yang Y, Du H, Zhou R, Zhao Y. How does water-nanotube interaction influence water flow through the nanochannel? J Chem Phys 2012; 136:175101. [DOI: 10.1063/1.4707346] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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Abstract
Water molecules confined to pores with sub-nanometre diameters form single-file hydrogen-bonded chains. In such nanoscale confinement, water has unusual physical properties that are exploited in biology and hold promise for a wide range of biomimetic and nanotechnological applications. The latter can be realized by carbon and boron nitride nanotubes which confine water in a relatively non-specific way and lend themselves to the study of intrinsic properties of single-file water. As a consequence of strong water-water hydrogen bonds, many characteristics of single-file water are conserved in biological and synthetic pores despite differences in their atomistic structures. Charge transport and orientational order in water chains depend sensitively on and are mainly determined by electrostatic effects. Thus, mimicking functions of biological pores with apolar pores and corresponding external fields gives insight into the structure-function relation of biological pores and allows the development of technical applications beyond the molecular devices found in living systems. In this Perspective, we revisit results for single-file water in apolar pores, and examine the similarities and the differences between these simple systems and water in more complex pores.
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Affiliation(s)
- Jürgen Köfinger
- Laboratory of Chemical Physics, Bldg. 5, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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Kaila VRI, Hummer G. Energetics and dynamics of proton transfer reactions along short water wires. Phys Chem Chem Phys 2011; 13:13207-15. [PMID: 21701719 PMCID: PMC3470879 DOI: 10.1039/c1cp21112a] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Proton transfer (pT) reactions in biochemical processes are often mediated by chains of hydrogen-bonded water molecules. We use hybrid density functional calculations to study pT along quasi one-dimensional water arrays that connect an imidazolium-imidazole proton donor-acceptor pair. We characterize the structures of intermediates and transition states, the energetics, and the dynamics of the pT reactions, including vibrational contributions to kinetic isotope effects. In molecular dynamics simulations of pT transition paths, we find that for short water chains with four water molecules, the pT reactions are semi-concerted. The formation of a high-energy hydronium intermediate next to the proton-donating group is avoided by a simultaneous transfer of a proton from the donor to the first water molecule, and from the first water molecule into the water chain. Lowering the dielectric constant of the environment and increasing the water chain length both reduce the barrier for pT. We study the effect of the driving force on the energetics of the pT reaction by changing the proton affinity of the donor and acceptor groups through halogen and methyl substitutions. We find that the barrier of the pT reaction depends linearly on the proton affinity of the donor but is nearly independent of the proton affinity of the acceptor, corresponding to Brønsted slopes of one and zero, respectively.
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Affiliation(s)
- Ville R. I. Kaila
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Memorial Drive, Bethesda, 20892 Maryland, USA. Fax: 301-496-0825; Tel: 301-402-6290
| | - Gerhard Hummer
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Memorial Drive, Bethesda, 20892 Maryland, USA. Fax: 301-496-0825; Tel: 301-402-6290
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14
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Kaila VRI, Verkhovsky MI, Wikström M. Proton-coupled electron transfer in cytochrome oxidase. Chem Rev 2010; 110:7062-81. [PMID: 21053971 DOI: 10.1021/cr1002003] [Citation(s) in RCA: 398] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ville R I Kaila
- Helsinki Bioenergetics Group, Structural Biology and Biophysics Program, Institute of Biotechnology, University of Helsinki, P.O. Box 65, FI-00014 Helsinki, Finland
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15
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Prakash M, Subramanian V, Gadre SR. Stepwise Hydration of Protonated Carbonic Acid: A Theoretical Study. J Phys Chem A 2009; 113:12260-75. [DOI: 10.1021/jp904576u] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. Prakash
- Chemical Laboratory, Central Leather Research Institute, Central Leather Research Institute, Adyar, Chennai 600 020, India, and Department of Chemistry, University of Pune, Pune 411 007, India
| | - V. Subramanian
- Chemical Laboratory, Central Leather Research Institute, Central Leather Research Institute, Adyar, Chennai 600 020, India, and Department of Chemistry, University of Pune, Pune 411 007, India
| | - Shridhar R. Gadre
- Chemical Laboratory, Central Leather Research Institute, Central Leather Research Institute, Adyar, Chennai 600 020, India, and Department of Chemistry, University of Pune, Pune 411 007, India
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16
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Abi TG, Anand A, Taraphder S. Proton Affinities of Some Amino Acid Side Chains in a Restricted Environment. J Phys Chem B 2009; 113:9570-6. [DOI: 10.1021/jp808606b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- T. G. Abi
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
| | - Amit Anand
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
| | - Srabani Taraphder
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
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18
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Rasaiah JC, Garde S, Hummer G. Water in Nonpolar Confinement: From Nanotubes to Proteins and Beyond. Annu Rev Phys Chem 2008; 59:713-40. [DOI: 10.1146/annurev.physchem.59.032607.093815] [Citation(s) in RCA: 586] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Shekhar Garde
- The Howard P. Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180;
| | - Gerhard Hummer
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520;
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Khavrutskii IV, McCammon JA. Generalized gradient-augmented harmonic Fourier beads method with multiple atomic and/or center-of-mass positional restraints. J Chem Phys 2007; 127:124901. [PMID: 17902931 DOI: 10.1063/1.2771172] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We describe a generalization of the gradient-augmented harmonic Fourier beads method for finding minimum free-energy transition path ensembles and similarly minimum potential energy paths to allow positional restraints on the centers of mass of selected atoms. The generalized gradient-augmented harmonic Fourier beads (ggaHFB) method further extends the scope of the HFB methodology to studying molecule transport across various mobile phases such as lipid membranes. Furthermore, the new implementation improves the applicability of the HFB method to studies of ligand binding, protein folding, and enzyme catalysis as well as modeling equilibrium pulling experiments. Like its predecessor, the ggaHFB method provides accurate energy profiles along the specified paths and in certain simple cases avoids the need for path optimization. The utility of the ggaHFB method is demonstrated with an application to the water permeation through a single-wall (5,5) carbon nanotube with a diameter of 6.78 A and length of 16.0 A. We provide a simple rationale as to why water enters the hydrophobic nanotube and why it does so in pulses and in wire assembly.
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Affiliation(s)
- Ilja V Khavrutskii
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, California 92093-0365, USA.
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20
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Hiebel AC, Lee YS, Bilsky E, Giuvelis D, Deschamps JR, Parrish DA, Aceto MD, May EL, Harris LS, Coop A, Dersch CM, Partilla JS, Rothman RB, Cheng K, Jacobson AE, Rice KC. Probes for narcotic receptor mediated phenomena. 34. Synthesis and structure-activity relationships of a potent mu-agonist delta-antagonist and an exceedingly potent antinociceptive in the enantiomeric C9-substituted 5-(3-hydroxyphenyl)-N-phenylethylmorphan series. J Med Chem 2007; 50:3765-76. [PMID: 17625813 DOI: 10.1021/jm061325e] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Both of the enantiomers of 5-(3-hydroxyphenyl)-N-phenylethylmorphan with C9alpha-methyl, C9-methylene, C9-keto, and C9alpha- and C9beta-hydroxy substituents were synthesized and pharmacologically evaluated. Three of the 10 compounds, (1R,5R,9S)-(-)-9-hydroxy-5-(3-hydroxyphenyl-2-phenylethyl-2-azabicyclo[3.3.1]nonane ((1R,5R,9S)-(-)-10), (1R,5S)-(+)-5-(3-hydroxyphenyl)-9-methylene-2-phenethyl-2-azabicyclo[3.3.1]nonane ((1R,5S)-(+)-14), and (1R,5S,9R)-(-)-5-(3-hydroxyphenyl)-9-methyl-2-phenethyl-2-azabicyclo[3.3.1]nonane ((1R,5S,9R)-(+)-15) had subnanomolar affinity at mu-opioid receptors (Ki = 0.19, 0.19, and 0.63 nM, respectively). The (1R,5S)-(+)-14 was found to be a mu-opioid agonist and a mu-, delta-, and kappa-antagonist in [35S]GTP-gamma-S assays and was approximately 50 times more potent than morphine in a number of acute and subchronic pain assays, including thermal and visceral models of nociception. The (1R,5R,9S)-(-)-10 compound with a C9-hydroxy substituent axially oriented to the piperidine ring (C9beta-hydroxy) was a mu-agonist about 500 times more potent than morphine. In the single-dose suppression assay, it was greater than 1000 times more potent than morphine. It is the most potent known phenylmorphan antinociceptive. The molecular structures of these compounds were energy minimized with density functional theory at the B3LYP/6-31G* level and then overlaid onto (1R,5R,9S)-(-)-10 using the heavy atoms in the morphan moiety as a common docking point. Based on modeling, the spatial arrangement of the protonated nitrogen atom and the 9beta-OH substituent in (1R,5R,9S)-(-)-10 may facilitate the alignment of a putative water chain enabling proton transfer to a nearby proton acceptor group in the mu-opioid receptor.
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MESH Headings
- Analgesics/chemical synthesis
- Analgesics/chemistry
- Analgesics/pharmacology
- Animals
- Bridged Bicyclo Compounds, Heterocyclic/chemical synthesis
- Bridged Bicyclo Compounds, Heterocyclic/chemistry
- Bridged Bicyclo Compounds, Heterocyclic/pharmacology
- CHO Cells
- Cricetinae
- Cricetulus
- Crystallography, X-Ray
- Haplorhini
- Humans
- Mice
- Models, Molecular
- Molecular Structure
- Quantum Theory
- Radioligand Assay
- Receptors, Opioid, delta/antagonists & inhibitors
- Receptors, Opioid, kappa/antagonists & inhibitors
- Receptors, Opioid, mu/agonists
- Stereoisomerism
- Structure-Activity Relationship
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Affiliation(s)
- Anne-Cécile Hiebel
- Drug Design and Synthesis Section, Chemical Biology Research Branch, National Institute on Drug Abuse, National Institutes of Health, DHHS, Bethesda, MD 20892, USA
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Dellago C, Hummer G. Kinetics and mechanism of proton transport across membrane nanopores. PHYSICAL REVIEW LETTERS 2006; 97:245901. [PMID: 17280300 DOI: 10.1103/physrevlett.97.245901] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2006] [Indexed: 05/07/2023]
Abstract
We use computer simulations to study the kinetics and mechanism of proton passage through a narrow-pore carbon-nanotube membrane separating reservoirs of liquid water. Free energy and rate constant calculations show that protons move across the membrane diffusively along single-file chains of hydrogen-bonded water molecules. Proton passage through the membrane is opposed by a high barrier in the effective potential, reflecting the large electrostatic penalty for desolvation and reminiscent of charge exclusion in biological water channels. At neutral pH, we estimate a translocation rate of about 1 proton per hour and tube.
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Affiliation(s)
- Christoph Dellago
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
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