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Ahmed SM, Ragunathan P, Shin J, Peter S, Kleissle S, Neuenschwander M, Schäfer R, Kries JPV, Grüber G, Dröge P. The FGFR inhibitor PD173074 binds to the C-terminus of oncofetal HMGA2 and modulates its DNA-binding and transcriptional activation functions. FEBS Lett 2023; 597:1977-1988. [PMID: 37259564 DOI: 10.1002/1873-3468.14675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/20/2023] [Accepted: 05/23/2023] [Indexed: 06/02/2023]
Abstract
The architectural chromatin factor high-mobility group AT-hook 2 (HMGA2) is causally involved in several human malignancies and pathologies. HMGA2 is not expressed in most normal adult somatic cells, which renders the protein an attractive drug target. An established cell-based compound library screen identified the fibroblast growth factor receptor (FGFR) inhibitor PD173074 as an antagonist of HMGA2-mediated transcriptional reporter gene activation. We determined that PD173074 binds the C-terminus of HMGA2 and interferes with functional coordination of the three AT-hook DNA-binding domains mediated by the C-terminus. The HMGA2-antagonistic effect of PD173074 on transcriptional activation may therefore result from an induced altered DNA-binding mode of HMGA2. PD173074 as a novel HMGA2-specific antagonist could trigger the development of derivates with enhanced attributes and clinical potential.
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Affiliation(s)
- Syed Moiz Ahmed
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
| | - Priya Ragunathan
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
| | - Joon Shin
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
| | - Sabrina Peter
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
| | - Sabrina Kleissle
- Max-Delbrück-Centrum für Molekulare Medizin in der Helmholtz-Gemeinschaft, Berlin, Germany
| | | | - Reinhold Schäfer
- Comprehensive Cancer Center, Charité Universitätsmedizin Berlin, Germany
- German Cancer Consortium, German Cancer Research Center, Heidelberg, Germany
| | - Jens Peter V Kries
- Leibniz-Forschungsinstitut fűr Molekulare Pharmakologie, Berlin, Germany
| | - Gerhard Grüber
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
| | - Peter Dröge
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
- LambdaGen Pte Ltd, Singapore City, Singapore
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2
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Fragment-Based and Structural Investigation for Discovery of JNK3 Inhibitors. Pharmaceutics 2022; 14:pharmaceutics14091900. [PMID: 36145648 PMCID: PMC9501523 DOI: 10.3390/pharmaceutics14091900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/02/2022] [Accepted: 09/05/2022] [Indexed: 11/21/2022] Open
Abstract
The c-Jun N-terminal kinases (JNKs) are members of the mitogen-activated protein kinase (MAPK) family and are related to cell proliferation, gene expression, and cell death. JNK isoform 3 (JNK3) is an important therapeutic target in varieties of pathological conditions including cancers and neuronal death. There is no approved drug targeting JNKs. To discover chemical inhibitors of JNK3, virtual fragment screening, the saturation transfer difference (STD) NMR, in vitro kinase assay, and X-ray crystallography were employed. A total of 27 fragments from the virtually selected 494 compounds were identified as initial hits via STD NMR and some compounds showed the inhibition of the activity of JNK3 in vitro. The structures of JNK3 with a fragment and a potent inhibitor were determined by X-ray crystallography. The fragment and inhibitor shared a common JNK3-binding feature. The result shows that fragment screening by NMR spectroscopy is a very efficient method to screen JNK3 binders and the structure of JNK3-inhibitor complex can be used to design and develop more potent inhibitors.
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Anesthetics and Cell-Cell Communication: Potential Ca 2+-Calmodulin Role in Gap Junction Channel Gating by Heptanol, Halothane and Isoflurane. Int J Mol Sci 2022; 23:ijms23169017. [PMID: 36012286 PMCID: PMC9409107 DOI: 10.3390/ijms23169017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 08/08/2022] [Accepted: 08/11/2022] [Indexed: 11/17/2022] Open
Abstract
Cell–cell communication via gap junction channels is known to be inhibited by the anesthetics heptanol, halothane and isoflurane; however, despite numerous studies, the mechanism of gap junction channel gating by anesthetics is still poorly understood. In the early nineties, we reported that gating by anesthetics is strongly potentiated by caffeine and theophylline and inhibited by 4-Aminopyridine. Neither Ca2+ channel blockers nor 3-isobutyl-1-methylxanthine (IBMX), forskolin, CPT-cAMP, 8Br-cGMP, adenosine, phorbol ester or H7 had significant effects on gating by anesthetics. In our publication, we concluded that neither cytosolic Ca2+i nor pHi were involved, and suggested a direct effect of anesthetics on gap junction channel proteins. However, while a direct effect cannot be excluded, based on the potentiating effect of caffeine and theophylline added to anesthetics and data published over the past three decades, we are now reconsidering our earlier interpretation and propose an alternative hypothesis that uncoupling by heptanol, halothane and isoflurane may actually result from a rise in cytosolic Ca2+ concentration ([Ca2+]i) and consequential activation of calmodulin linked to gap junction proteins.
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Wang Y, Yang E, Wells MM, Bondarenko V, Woll K, Carnevale V, Granata D, Klein ML, Eckenhoff RG, Dailey WP, Covarrubias M, Tang P, Xu Y. Propofol inhibits the voltage-gated sodium channel NaChBac at multiple sites. J Gen Physiol 2018; 150:1317-1331. [PMID: 30018039 PMCID: PMC6122922 DOI: 10.1085/jgp.201811993] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 05/02/2018] [Accepted: 06/15/2018] [Indexed: 12/24/2022] Open
Abstract
Voltage-gated sodium (NaV) channels are important targets of general anesthetics, including the intravenous anesthetic propofol. Electrophysiology studies on the prokaryotic NaV channel NaChBac have demonstrated that propofol promotes channel activation and accelerates activation-coupled inactivation, but the molecular mechanisms of these effects are unclear. Here, guided by computational docking and molecular dynamics simulations, we predict several propofol-binding sites in NaChBac. We then strategically place small fluorinated probes at these putative binding sites and experimentally quantify the interaction strengths with a fluorinated propofol analogue, 4-fluoropropofol. In vitro and in vivo measurements show that 4-fluoropropofol and propofol have similar effects on NaChBac function and nearly identical anesthetizing effects on tadpole mobility. Using quantitative analysis by 19F-NMR saturation transfer difference spectroscopy, we reveal strong intermolecular cross-relaxation rate constants between 4-fluoropropofol and four different regions of NaChBac, including the activation gate and selectivity filter in the pore, the voltage sensing domain, and the S4-S5 linker. Unlike volatile anesthetics, 4-fluoropropofol does not bind to the extracellular interface of the pore domain. Collectively, our results show that propofol inhibits NaChBac at multiple sites, likely with distinct modes of action. This study provides a molecular basis for understanding the net inhibitory action of propofol on NaV channels.
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Affiliation(s)
- Yali Wang
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Elaine Yang
- Department of Neuroscience and Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College and Jefferson College of Biomedical Sciences, Thomas Jefferson University, Philadelphia, PA
| | - Marta M Wells
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Vasyl Bondarenko
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Kellie Woll
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA
| | - Vincenzo Carnevale
- Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, PA
| | - Daniele Granata
- Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, PA
| | - Michael L Klein
- Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, PA
| | - Roderic G Eckenhoff
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA
| | - William P Dailey
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA
| | - Manuel Covarrubias
- Department of Neuroscience and Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College and Jefferson College of Biomedical Sciences, Thomas Jefferson University, Philadelphia, PA
| | - Pei Tang
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Yan Xu
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA
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Magalhães J, Annunziato G, Franko N, Pieroni M, Campanini B, Bruno A, Costantino G. Integration of Enhanced Sampling Methods with Saturation Transfer Difference Experiments to Identify Protein Druggable Pockets. J Chem Inf Model 2018; 58:710-723. [DOI: 10.1021/acs.jcim.7b00733] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Joana Magalhães
- Food and Drug Department, P4T group, Parco Area Delle Scienze 27/A−43124, Parma, Italy
| | | | - Nina Franko
- Food and Drug Department, Laboratory of Biochemistry and Molecular Biology, Parco Area Delle Scienze 23/A−43124, Parma, Italy
| | - Marco Pieroni
- Food and Drug Department, P4T group, Parco Area Delle Scienze 27/A−43124, Parma, Italy
| | - Barbara Campanini
- Food and Drug Department, Laboratory of Biochemistry and Molecular Biology, Parco Area Delle Scienze 23/A−43124, Parma, Italy
| | - Agostino Bruno
- Food and Drug Department, P4T group, Parco Area Delle Scienze 27/A−43124, Parma, Italy
- Experimental Therapeutics Program, IFOM−The FIRC Institute for Molecular Oncology Foundation, Via Adamello 16−20139, Milano, Italy
| | - Gabriele Costantino
- Food and Drug Department, P4T group, Parco Area Delle Scienze 27/A−43124, Parma, Italy
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Cieślik-Boczula K, Rospenk M. Interaction of anesthetic molecules with α-helix and polyproline II extended helix of long-chain poly-l-lysine. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 189:436-442. [PMID: 28843877 DOI: 10.1016/j.saa.2017.08.045] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 07/24/2017] [Accepted: 08/14/2017] [Indexed: 06/07/2023]
Abstract
The effect of halothane, enflurane, sevoflurane, and isoflurane molecules, as volatile anesthetics, on the α-helices and polyproline II extended helices (PPII) of long-chain poly-l-lysine (PLL) were studied using Fourier-transform infrared and vibrational circular dichroism spectroscopy. Uncharged and charged α-helices, as well as charged extended PPII helices, were subjected to anesthetic actions in solvents with different pD values or methanol to water ratios. A crucial factor responsible for hindering the anesthetic-PLL interactions is shown to be the ionization of amino groups of the PLL side chains. The α-helix to β-sheet transition was triggered only for the uncharged α-helical structures of PLL by the nonpolar anesthetics under study.
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Affiliation(s)
| | - Maria Rospenk
- Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie 14, 50-383 Wroclaw, Poland
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7
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Molecular study of mucin-procyanidin interaction by fluorescence quenching and Saturation Transfer Difference (STD)-NMR. Food Chem 2017; 228:427-434. [DOI: 10.1016/j.foodchem.2017.02.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 02/02/2017] [Accepted: 02/06/2017] [Indexed: 11/18/2022]
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Abstract
During the past decade fragment-based drug discovery (FBDD) has rapidly evolved and several drugs or drug candidates developed by FBDD approach are clinically in use or in clinical trials. For example, vemurafenib, a V600E mutated BRAF inhibitor, was developed by utilizing FBDD approach and approved by FDA in 2011. In FBDD, screening of fragments is the starting step for identification of hits and lead generation. Fragment screening usually relies on biophysical techniques by which the protein-bound small molecules can be detected. NMR spectroscopy has been extensively used to study the molecular interaction between the protein and the ligand, and has many advantages in fragment screening over other biophysical techniques. This chapter describes the practical aspects of fragment screening by saturation transfer difference NMR.
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Affiliation(s)
- Byeonggu Han
- Department of Pharmacy, Dongguk University-Seoul, 32 Dongguk-ro, Ilsandong-gu, Goyang, Gyeonggi, 410-820, Republic of Korea
| | - Hee-Chul Ahn
- Department of Pharmacy, Dongguk University-Seoul, 32 Dongguk-ro, Ilsandong-gu, Goyang, Gyeonggi, 410-820, Republic of Korea.
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9
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Zhang C, Zhuo Y, Moniz HA, Wang S, Moremen KW, Prestegard JH, Brown EM, Yang JJ. Direct determination of multiple ligand interactions with the extracellular domain of the calcium-sensing receptor. J Biol Chem 2014; 289:33529-42. [PMID: 25305020 DOI: 10.1074/jbc.m114.604652] [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] [Indexed: 01/16/2023] Open
Abstract
Numerous in vivo functional studies have indicated that the dimeric extracellular domain (ECD) of the CaSR plays a crucial role in regulating Ca(2+) homeostasis by sensing Ca(2+) and l-Phe. However, direct interaction of Ca(2+) and Phe with the ECD of the receptor and the resultant impact on its structure and associated conformational changes have been hampered by the large size of the ECD, its high degree of glycosylation, and the lack of biophysical methods to monitor weak interactions in solution. In the present study, we purified the glycosylated extracellular domain of calcium-sensing receptor (CaSR) (ECD) (residues 20-612), containing either complex or high mannose N-glycan structures depending on the host cell line employed for recombinant expression. Both glycosylated forms of the CaSR ECD were purified as dimers and exhibit similar secondary structures with ∼ 50% α-helix, ∼ 20% β-sheet content, and a well buried Trp environment. Using various spectroscopic methods, we have shown that both protein variants bind Ca(2+) with a Kd of 3.0-5.0 mm. The local conformational changes of the proteins induced by their interactions with Ca(2+) were visualized by NMR with specific (15)N Phe-labeled forms of the ECD. Saturation transfer difference NMR approaches demonstrated for the first time a direct interaction between the CaSR ECD and l-Phe. We further demonstrated that l-Phe increases the binding affinity of the CaSR ECD for Ca(2+). Our findings provide new insights into the mechanisms by which Ca(2+) and amino acids regulate the CaSR and may pave the way for exploration of the structural properties of CaSR and other members of family C of the GPCR superfamily.
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Affiliation(s)
- Chen Zhang
- From the Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30303
| | - You Zhuo
- From the Department of Chemistry
| | - Heather A Moniz
- the Department of Biochemistry and Molecular Biology and the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, and
| | - Shuo Wang
- the Department of Biochemistry and Molecular Biology and the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, and
| | - Kelley W Moremen
- the Department of Biochemistry and Molecular Biology and the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, and
| | - James H Prestegard
- the Department of Biochemistry and Molecular Biology and the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, and
| | - Edward M Brown
- the Department of Medicine, Division of Endocrinology, Brigham and Women's Hospital, Boston, Massachusetts 02115
| | - Jenny J Yang
- From the Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30303,
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Application of NMR spectroscopy in the development of a biomimetic approach for hydrophobic drug association with physical hydrogels. Colloids Surf B Biointerfaces 2014; 115:391-9. [DOI: 10.1016/j.colsurfb.2013.12.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 12/11/2013] [Accepted: 12/14/2013] [Indexed: 11/20/2022]
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11
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Brath U, Lau K, Van Petegem F, Erdélyi M. Mapping the sevoflurane-binding sites of calmodulin. Pharmacol Res Perspect 2014; 2:5. [PMID: 25505574 PMCID: PMC4186402 DOI: 10.1002/prp2.25] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 01/06/2014] [Indexed: 11/21/2022] Open
Abstract
General anesthetics, with sevoflurane (SF) being the first choice inhalational anesthetic agent, provide reversible, broad depressor effects on the nervous system yet have a narrow margin of safety. As characterization of low-affinity binding interactions of volatile substances is exceptionally challenging with the existing methods, none of the numerous cellular targets proposed as chief protagonists in anesthesia could yet be confirmed. The recognition that most critical functions modulated by volatile anesthetics are under the control of intracellular Ca2+ concentration, which in turn is primarily regulated by calmodulin (CaM), motivated us for characterization of the SF–CaM interaction. Solution NMR (Nuclear Magnetic Resonance) spectroscopy was used to identify SF-binding sites using chemical shift displacement, NOESY and heteronuclear Overhauser enhancement spectroscopy (HOESY) experiments. Binding affinities were measured using ITC (isothermal titration calorimetry). SF binds to both lobes of (Ca2+)4-CaM with low mmol/L affinity whereas no interaction was observed in the absence of Ca2+. SF does not affect the calcium binding of CaM. The structurally closely related SF and isoflurane are shown to bind to the same clefts. The SF-binding clefts overlap with the binding sites of physiologically relevant ion channels and bioactive small molecules, but the binding affinity suggests it could only interfere with very weak CaM targets.
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Affiliation(s)
- Ulrika Brath
- Department of Chemistry and Molecular Biology and the Swedish NMR Centre, University of Gothenburg SE-412 96, Gothenburg, Sweden
| | - Kelvin Lau
- Department of Biochemistry and Molecular Biology, University of British Columbia Vancouver, British Columbia, V6T 1Z3, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia Vancouver, British Columbia, V6T 1Z3, Canada
| | - Máté Erdélyi
- Department of Chemistry and Molecular Biology and the Swedish NMR Centre, University of Gothenburg SE-412 96, Gothenburg, Sweden
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Gonçalves R, Mateus N, De Freitas V. Influence of carbohydrates on the interaction of procyanidin B3 with trypsin. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:11794-11802. [PMID: 21950419 DOI: 10.1021/jf203060s] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The biological properties of procyanidins, in particular their inhibition of digestive enzymes, have received much attention in the past few years. Dietary carbohydrates are an environmental factor that is known to affect the interaction of procyanidins with proteins. This work aimed at understanding the effect of ionic food carbohydrates (polygalacturonic acid, arabic gum, pectin, and xanthan gum) on the interaction between procyanidins and trypsin. Physical-chemical techniques such as saturation transfer difference-NMR (STD-NMR) spectroscopy, fluorescence quenching, and nephelometry were used to evaluate the interaction process. Using STD-NMR, it was possible to identify the binding of procyanidin B3 to trypsin. The tested carbohydrates prevented the association of procyanidin B3 and trypsin by a competition mechanism in which the ionic character of carbohydrates and their ability to encapsulate procyanidins seem crucial leading to a reduction in STD signal and light scattering and to a recovery of the proteins intrinsic fluorescence. On the basis of these results, it was possible to grade the carbohydrates in their aggregation inhibition ability: XG > PA > AG ≫ PC. These effects may be relevant since the coingestion of procyanidins and ionic carbohydrates are frequent and furthermore since these might negatively affect the antinutritional properties ascribed to procyanidins in the past.
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Affiliation(s)
- Rui Gonçalves
- Centro de Investigação em Química, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
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Gonçalves R, Mateus N, Pianet I, Laguerre M, de Freitas V. Mechanisms of tannin-induced trypsin inhibition: a molecular approach. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:13122-13129. [PMID: 21877746 DOI: 10.1021/la202280c] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Association of procyanidins with enzymes has drawn attention over the past few years. This work aimed to bring insights on interaction of the protease trypsin with the procyanidin dimer (B3). This interaction was characterized by fluorescence quenching, saturation transfer difference (STD) NMR, molecular modeling, and through an enzymatic inhibition assay. Further studies were conducted regarding the influence of pectin on the binding process. A general overview of the binding process may be outlined as follows: a) at low procyanidin concentrations (below the critical micellar concentration-(CMC)) a specific interaction probably driven by hydrogen bonds between the protein backbone and the procyanidin occurs and is associated with the reduction of both enzyme activity and fluorescence; b) at high procyanidin concentration (above the CMC) the interaction becomes nonspecific. This variation in both nature and extent of the interaction with the variation of procyanidin concentration shows how tannin self-association may affect the interaction between tannins and proteins. It was also shown that the mechanism through which pectin affects the interaction between procyanidin B3 and trypsin is of a competitive type.
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Affiliation(s)
- Rui Gonçalves
- Centro de Investigação em Química, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
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14
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Nishimoto M, Komatsu U, Tamai N, Yamanaka M, Kaneshina S, Ogli K, Matsuki H. Intrinsic interaction mode of an inhalation anesthetic with globular proteins: a comparative study on ligand recognition. Colloid Polym Sci 2011. [DOI: 10.1007/s00396-011-2491-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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15
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Cabeça LF, Figueiredo IM, de Paula E, Marsaioli AJ. Prilocaine-cyclodextrin-liposome: effect of pH variations on the encapsulation and topology of a ternary complex using 1H NMR. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2011; 49:295-300. [PMID: 21452355 DOI: 10.1002/mrc.2740] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 01/10/2011] [Accepted: 01/18/2011] [Indexed: 05/30/2023]
Abstract
A better comprehension of the prilocaine (PLC)-β-cyclodextrin (β-CD) complex liberation to membranes was provided by studying the architectural supramolecular arrangements of PLC, β-CD and egg phosphatidylcholine (EPC) liposomes, a membrane model. The topologies and possible interactions of mixtures of PLC, β-CD and EPC liposomes were investigated by nuclear magnetic resonances combining experimental (1)H-NMR (1D ROESY, STD and DOSY) at different pHs. The results indicate that in the mixture PLC/β-CD/EPC at pH 10 the PLC molecules are almost totally embedded into the liposomes and little interaction was observed between PLC and β-CD. However, at pH 5.5 not only was PLC imbedded in the EPC bilayer, but PLC was also interacting with β-CD. These results were rationalized as a spontaneous PLC release from β-CD to liposomes vesicles, whereas the PLC/EPC complex formation was higher at pH 10 than pH 5.5.
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Xia Y, Zhu Q, Jun KY, Wang J, Gao X. Clean STD-NMR spectrum for improved detection of ligand-protein interactions at low concentration of protein. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2010; 48:918-924. [PMID: 20957656 DOI: 10.1002/mrc.2687] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Saturation transfer difference (STD)-NMR has been widely used to screen ligand compound libraries for their binding activities to proteins and to determine the binding epitopes of the ligands. We report herein, a Clean STD-NMR method developed to overcome false positives (artifacts) observed in the STD-NMR spectrum due to the power spillover of RF irradiation. The method achieved higher degree of resonance saturation through digital editing of two STD-NMR spectra to generate a concatenated difference spectrum and three times of sensitivity enhancement for a loose binding complex involving DNA oligonucleotide and an RNA-binding protein, CUGBP-1ab (25.2 kDa). The interesting binding characteristics of the complex dCTGTCT-CUGBP1ab were obtained. The method was applied to a mixture of small ligand and bovine serum albumin protein (BSA, 66.3 kDa), and detected the intermolecular contacts at a BSA concentration as low as 0.1 µM, a working concentration useful for the detection of proteins of low solubility at biologically relevant conditions.
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Affiliation(s)
- Youlin Xia
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77004, USA.
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Zhao L, Wu Q, Cheng Y, Zhang J, Wu J, Xu T. High-Throughput Screening of Dendrimer-Binding Drugs. J Am Chem Soc 2010; 132:13182-4. [DOI: 10.1021/ja106128u] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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18
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Huang C, Mohanty S, Banerjee M. A novel method of production and biophysical characterization of the catalytic domain of yeast oligosaccharyl transferase. Biochemistry 2010; 49:1115-26. [PMID: 20047336 DOI: 10.1021/bi902181v] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Oligosaccharyl transferase (OT) is a multisubunit enzyme that catalyzes N-linked glycosylation of nascent polypeptides in the lumen of the endoplasmic reticulum. In the case of Saccharomyces cerevisiae, OT is composed of nine integral membrane protein subunits. Defects in N-linked glycosylation cause a series of disorders known as congenital disorders of glycosylation (CDG). The C-terminal domain of the Stt3p subunit has been reported to contain the acceptor protein recognition site and/or catalytic site. We report here the subcloning, overexpression, and a robust but novel method of production of the pure C-terminal domain of Stt3p at 60-70 mg/L in Escherichia coli. CD spectra indicate that the C-terminal Stt3p is highly helical and has a stable tertiary structure in SDS micelles. The well-dispersed two-dimensional (1)H-(15)N HSQC spectrum in SDS micelles indicates that it is feasible to determine the atomic structure by NMR. The effect of the conserved D518E mutation on the conformation of the C-terminal Stt3p is particularly interesting. The replacement of a key residue, Asp(518), located within the WWDYG signature motif (residues 516-520), led to a distinct tertiary structure, even though both proteins have similar overall secondary structures, as demonstrated by CD, fluorescence and NMR spectroscopies. This observation strongly suggests that Asp(518) plays a critical structural role, in addition to the previously proposed catalytic role. Moreover, the activity of the protein was confirmed by saturation transfer difference and nuclear magnetic resonance titration studies.
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Affiliation(s)
- Chengdong Huang
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, USA
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Piazza M, Yu L, Teghanemt A, Gioannini T, Weiss J, Peri F. Evidence of a specific interaction between new synthetic antisepsis agents and CD14. Biochemistry 2010; 48:12337-44. [PMID: 19928913 DOI: 10.1021/bi901601b] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Synthetic molecules derived from natural sugars with a positively charged amino group or ammonium salt and two lipophilic chains have been shown to inhibit TLR4 activation in vitro and in vivo. To characterize the mechanism of action of this class of molecules, we investigated possible interactions with the extracellular components that bind and shuttle endotoxin [lipopolysaccharide (LPS)] to TLR4, namely, LBP, CD14, and MD-2. Molecules that inhibited TLR4 activation inhibited LBP.CD14-dependent transfer of endotoxin monomers derived from aggregates of tritiated lipooligosaccharide ([(3)H]LOS) from Neisseria meninigitidis to MD-2.TLR4, resulting in a reduced level of formation of a ([(3)H]LOS.MD-2.TLR4(ECD))(2) (M(r) approximately 190000) complex. This effect was due to inhibition of the transfer of [(3)H]LOS from aggregates in solution to sCD14 with little or no effect on [(3)H]LOS shuttling from [(3)H]LOS.sCD14 to MD-2. These compounds also inhibited transfer of the [(3)H]LOS monomer from full-length CD14 to a truncated, polyhistidine-tagged CD14. Dose-dependent inhibition of the transfer of [(3)H]LOS between the two forms of CD14 was observed with each of three different synthetic compounds that inhibited TLR4 activation but not by another structurally related analogue that lacked TLR4 antagonistic activity. Saturation transfer difference (STD) NMR data showed direct binding to CD14 by the synthetic TLR4 antagonist mediated principally through the lipid chains of the synthetic compound. Taken together, our findings strongly suggest that these compounds inhibit TLR4 activation by endotoxin by competitively occupying CD14 and thereby reducing the level of delivery of activating endotoxin to MD-2.TLR4.
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Affiliation(s)
- Matteo Piazza
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy
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Cabeça LF, Pickholz M, de Paula E, Marsaioli AJ. Liposome−Prilocaine Interaction Mapping Evaluated through STD NMR and Molecular Dynamics Simulations. J Phys Chem B 2009; 113:2365-70. [DOI: 10.1021/jp8069496] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Luís F. Cabeça
- Institute of Chemistry, UNICAMP, CP 6154, 13083-970 Campinas, SP, Brazil, and Institute of Biology, UNICAMP, CP 6109, 13083-970 Campinas, SP, Brazil
| | - Mónica Pickholz
- Institute of Chemistry, UNICAMP, CP 6154, 13083-970 Campinas, SP, Brazil, and Institute of Biology, UNICAMP, CP 6109, 13083-970 Campinas, SP, Brazil
| | - Eneida de Paula
- Institute of Chemistry, UNICAMP, CP 6154, 13083-970 Campinas, SP, Brazil, and Institute of Biology, UNICAMP, CP 6109, 13083-970 Campinas, SP, Brazil
| | - Anita J. Marsaioli
- Institute of Chemistry, UNICAMP, CP 6154, 13083-970 Campinas, SP, Brazil, and Institute of Biology, UNICAMP, CP 6109, 13083-970 Campinas, SP, Brazil
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Viegas A, Macedo AL, Cabrita EJ. Ligand-based nuclear magnetic resonance screening techniques. Methods Mol Biol 2009; 572:81-100. [PMID: 20694687 DOI: 10.1007/978-1-60761-244-5_6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A critical step in the drug discovery process is the identification of high-affinity ligands for macromolecular targets, and, over the last 10 years, NMR spectroscopy has become a powerful tool in the pharmaceutical industry. Instrumental improvements in recent years have contributed significantly to this development. Digital recording, cryogenic probes, autosamplers, and higher magnetic fields shorten the time for data acquisition and improve the spectral quality. In addition, new experiments and pulse sequences make a vast amount of information available for the drug discovery process. All these techniques take advantage of the fact that upon complex formation between a target molecule and a ligand, significant perturbations can be observed in NMR-sensitive parameters of either the target or the ligand. These perturbations can be used qualitatively to detect ligand binding or quantitatively to assess the strength of the binding interaction. In addition, some of the techniques allow the identification of the ligand-binding site or which part of the ligand is responsible for interacting with the target.In this chapter, we will use examples from our own research to illustrate how NMR experiments to characterize ligand binding may be used to both screen for novel compounds during the process of lead generation, and provide structural information useful for lead optimization during the latter stages of a discovery program.
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Affiliation(s)
- Aldino Viegas
- REQUIMTE, Department of Chemistry, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
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Canlas CG, Cui T, Li L, Xu Y, Tang P. Anesthetic modulation of protein dynamics: insight from an NMR study. J Phys Chem B 2008; 112:14312-8. [PMID: 18821786 DOI: 10.1021/jp805952w] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Mistic (membrane integrating sequence for translation of integral membrane protein constructs) comprises the four-alpha-helix bundle scaffold found in the transmembrane domains of the Cys-loop receptors that are plausible targets for general anesthetics. Nuclear magnetic resonance (NMR) studies of anesthetic halothane interaction with Mistic in dodecyl phosphocholine (DPC) micelles provide an experimental basis for understanding molecular mechanisms of general anesthesia. Halothane was found to interact directly with Mistic, mostly in the interfacial loop regions. Although the presence of halothane had little effect on Mistic structure, (15)N NMR relaxation dispersion measurements revealed that halothane affected Mistic's motion on the microsecond-millisecond time scale. Halothane shifted the equilibrium of chemical exchange in some residues and made the exchange faster or slower in comparison to the original state in the absence of halothane. The motion on the microsecond-millisecond time scale in several residues disappeared in response to the addition of halothane. Most of the residues experiencing halothane-induced dynamics changes also exhibited profound halothane-induced changes in chemical shift, suggesting that dynamics modification of these residues might result from their direct interaction with halothane molecules. Allosteric modulation by halothane also contributed to dynamics changes, as reflected in residues I52 and Y82 where halothane introduction brought about dynamics changes but not chemical shift changes. The study suggests that inhaled general anesthetics could act on proteins via altering protein motion on the microsecond-millisecond time scale, especially motion in the flexible loops that link different alpha helices. The validation of anesthetic effect on protein dynamics that are potentially correlated with protein functions is a critical step in unraveling the mechanisms of anesthetic action on proteins.
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Affiliation(s)
- Christian G Canlas
- Department of Anesthesiology, Pharmacology and Chemical Biology, and Computational Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA
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Streiff JH, Jones KA. Volatile anesthetic binding to proteins is influenced by solvent and aliphatic residues. J Chem Inf Model 2008; 48:2066-73. [PMID: 18808106 DOI: 10.1021/ci800206a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The main objective of this work was to characterize VA binding sites in multiple anesthetic target proteins. A computational algorithm was used to quantify the solvent exclusion and aliphatic character of amphiphilic pockets in the structures of VA binding proteins. VA binding sites in the protein structures were defined as the pockets with solvent exclusion and aliphatic character that exceeded minimum values observed in the VA binding sites of serum albumin, firefly luciferase, and apoferritin. We found that the structures of VA binding proteins are enriched in these pockets and that the predicted binding sites were consistent with experimental determined binding locations in several proteins. Autodock3 was used to dock the simulated molecules of 1,1,1,2,2-pentafluoroethane, difluoromethyl 1,1,1,2-tetrafluoroethyl ether, and sevoflurane and the isomers of halothane and isoflurane into these potential binding sites. We found that the binding of the various VA molecules to the amphiphilic pockets is driven primarily by VDW interactions and to a lesser extent by weak hydrogen bonding and electrostatic interactions. In addition, the trend in Delta G binding values follows the Meyer-Overton rule. These results suggest that VA potencies are related to the VDW interactions between the VA ligand and protein target. It is likely that VA bind to sites with a high degree of solvent exclusion and aliphatic character because aliphatic residues provide favorable VDW contacts and weak hydrogen bond donors. Water molecules occupying these sites maintain pocket integrity, associate with the VA ligand, and diminish the unfavorable solvation enthalpy of the VA. Water molecules displaced into the bulk by the VA ligand may provide an additional favorable enthalpic contribution to VA binding. Anesthesia is a component of many health related procedures, the outcomes of which could be improved with a better understanding of the molecular targets and mechanisms of anesthetic action.
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Affiliation(s)
- John H Streiff
- Department of Anesthesiology, University of Alabama at Birmingham, 901 19th Street South, Birmingham, AL 35294-1150, USA.
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Abstract
The molecular basis of anesthetic interaction with membrane proteins has been explored via determination of anesthetic effects on the structure and dynamics of the extended second transmembrane domain (TM2e) of the human neuronal nicotinic acetylcholine receptor (nAChR) beta(2) subunit in dodecylphosphocholine (DPC) micelles by (1)H and (15)N solution-state NMR. Both 1-chloro-1,2,2-trifluorocyclobutane (F3) and isoflurane, two volatile general anesthetics, induced nonuniform changes in chemical shifts among residues in TM2e. Saturation transfer difference NMR experiments further confirmed the direct anesthetic interaction with TM2e. A significant and more specific anesthetic interaction was observed on three leucine residues at the helix C-terminus. Although the TM2e helical structure remained after addition of anesthetics, plausible shortening and lengthening of helix hydrogen bonds were evidenced by periodic changes in backbone amide chemical shifts. The TM2e backbone dynamics were determined on the basis of the (15)N relaxation rate constants, R(1) and R(2), and the (15)N-[(1)H] NOE using the model-free approach. The global tumbling time (11.7 ns) of TM2e in micelles slightly increased ( approximately 12.3-12.5 ns) in the presence of anesthetics. The order parameter, S(2), exceeded 0.9 for all (15)N-labeled residues, showing a restricted internal motion. Anesthetics appear to have minor effect on the TM2e's internal motion. This study provided the basis for subsequent more comprehensive studies of anesthetic effects on the transmembrane domain complex of neuronal nAChR.
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Cutting B, Shelke SV, Dragic Z, Wagner B, Gathje H, Kelm S, Ernst B. Sensitivity enhancement in saturation transfer difference (STD) experiments through optimized excitation schemes. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2007; 45:720-4. [PMID: 17603821 DOI: 10.1002/mrc.2033] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Investigation of ligand-protein interactions by the saturation transfer difference (STD) experiment has been well established in the drug discovery process through numerous examples. Thus, binding epitopes may be mapped by comparing signals of the ligand with and without saturation of the protein. Herein, it is shown that a less selective process allows more protons to assist in the saturation of the protein, thereby considerably enhancing the sensitivity of the STD experiment. Increasing the saturation power entails a greater risk of perturbing the ligand; however, an amplitude modulation of the waveform assists this procedure by distributing the applied energy in sidebands.
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Affiliation(s)
- Brian Cutting
- University of Basel, Institute of Molecular Pharmacy, Klingelbergstrasse 50, CH-4056 Basel, Switzerland.
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Brecker L, Straganz GD, Tyl CE, Steiner W, Nidetzky B. Saturation–transfer–difference NMR to characterize substrate binding recognition and catalysis of two broadly specific glycoside hydrolases. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.molcatb.2006.07.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Streiff JH, Allen TW, Atanasova E, Juranic N, Macura S, Penheiter AR, Jones KA. Prediction of volatile anesthetic binding sites in proteins. Biophys J 2006; 91:3405-14. [PMID: 16877516 PMCID: PMC1614498 DOI: 10.1529/biophysj.106.082586] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Computational methods designed to predict and visualize ligand protein binding interactions were used to characterize volatile anesthetic (VA) binding sites and unoccupied pockets within the known structures of VAs bound to serum albumin, luciferase, and apoferritin. We found that both the number of protein atoms and methyl hydrogen, which are within approximately 8 A of a potential ligand binding site, are significantly greater in protein pockets where VAs bind. This computational approach was applied to structures of calmodulin (CaM), which have not been determined in complex with a VA. It predicted that VAs bind to [Ca(2+)](4)-CaM, but not to apo-CaM, which we confirmed with isothermal titration calorimetry. The VA binding sites predicted for the structures of [Ca(2+)](4)-CaM are located in hydrophobic pockets that form when the Ca(2+) binding sites in CaM are saturated. The binding of VAs to these hydrophobic pockets is supported by evidence that halothane predominantly makes contact with aliphatic resonances in [Ca(2+)](4)-CaM (nuclear Overhauser effect) and increases the Ca(2+) affinity of CaM (fluorescence spectroscopy). Our computational analysis and experiments indicate that binding of VA to proteins is consistent with the hydrophobic effect and the Meyer-Overton rule.
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Affiliation(s)
- John H Streiff
- Departments of Anesthesiology and Molecular Pharmacology and Experimental Therapeutics and Biochemistry and Molecular Biology, Mayo College of Medicine, Rochester, Minnesota, USA.
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