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Wetzel EA, Hanson AM, Troutfetter CL, Burkett DJ, Sem DS, Donaldson WA. Synthesis and evaluation of 17α-triazolyl and 9α-cyano derivatives of estradiol. Bioorg Med Chem 2020; 28:115670. [PMID: 32912438 PMCID: PMC10725730 DOI: 10.1016/j.bmc.2020.115670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 07/14/2020] [Accepted: 07/22/2020] [Indexed: 10/23/2022]
Abstract
A variety of 17α-triazolyl and 9α-cyano derivatives of estradiol were prepared and evaluated for binding to human ERβ in both a TR-FRET assay, as well as ERβ and ERα agonism in cell-based functional assays. 9α-Cyanoestradiol (5) was nearly equipotent as estradiol as an agonist for both ERβ and ERα. The potency of the 17α-triazolylestradiol analogs is considerably more variable and depends on the nature of the 4-substituent of the triazole ring. While rigid protein docking simulations exhibited significant steric clashing, induced fit docking providing more protein flexibility revealed that the triazole linker of analogs 2d and 2e extends outside of the traditional ligand binding domain with the benzene ring located in the loop connecting helix 11 to helix 12.
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Affiliation(s)
- Edward A Wetzel
- Department of Chemistry, Marquette University, P. O. Box 1881, Milwaukee, WI 53201-1881, United States
| | - Alicia M Hanson
- School of Pharmacy, Center for Structure-based Drug Design and Development, Concordia University Wisconsin, Mequon, WI 53097, United States
| | - Callie L Troutfetter
- School of Pharmacy, Center for Structure-based Drug Design and Development, Concordia University Wisconsin, Mequon, WI 53097, United States
| | - Daniel J Burkett
- Department of Chemistry, Marquette University, P. O. Box 1881, Milwaukee, WI 53201-1881, United States
| | - Daniel S Sem
- School of Pharmacy, Center for Structure-based Drug Design and Development, Concordia University Wisconsin, Mequon, WI 53097, United States
| | - William A Donaldson
- Department of Chemistry, Marquette University, P. O. Box 1881, Milwaukee, WI 53201-1881, United States.
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2
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Abstract
An enantioselective synthesis of the indole diterpenoid natural product paspaline is disclosed. Critical to this approach was the implementation of stereoselective desymmetrization reactions to assemble key stereocenters of the molecule. The design and execution of these tactics are described in detail, and a thorough analysis of observed outcomes is presented, ultimately providing the title compound in high stereopurity. This synthesis provides a novel template for preparing key stereocenters in this family of molecules, and the reactions developed en route to paspaline present a series of new synthetic disconnections in preparing steroidal natural products.
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Affiliation(s)
- Robert J. Sharpe
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Jeffrey S. Johnson
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
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3
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Sharpe RJ, Johnson JS. A global and local desymmetrization approach to the synthesis of steroidal alkaloids: stereocontrolled total synthesis of paspaline. J Am Chem Soc 2015; 137:4968-71. [PMID: 25856767 PMCID: PMC4409926 DOI: 10.1021/jacs.5b02631] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A stereocontrolled total synthesis of the indole diterpenoid natural product paspaline is described. Key steps include a highly diastereoselective enzymatic desymmetrization, substrate-directed epoxidation, Ireland-Claisen rearrangement, and diastereotopic group selective C-H acetoxylation to assemble the target with excellent stereofidelity. The route and results described herein outline complementary conceptual disconnections in the arena of steroid natural product synthesis.
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Affiliation(s)
- Robert J. Sharpe
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Jeffrey S. Johnson
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
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4
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Morozkina SN, Chentsova AS, Selivanov SI, Shavva AG. Synthesis and investigation of biological properties of modified 6-oxa-estra-1,3,5(10),8(9)-tetraenes. Steroids 2014; 88:90-4. [PMID: 24858337 DOI: 10.1016/j.steroids.2014.05.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 04/21/2014] [Accepted: 05/13/2014] [Indexed: 11/22/2022]
Abstract
To investigate the relationship between structure and biological activity of analogues of steroid estrogens we have developed the synthesis of 7α-methyl-6-oxa-estra-1,3,5(10),8(9)-tetraenes with cis- and trans-junction of C and D rings. We found that such compounds have stronger osteoprotective, cholesterol-lowering and antioxidant properties in comparison with uterotrophic activity; that is the advantage in comparison with clinically used 17α-ethynylestradiol.
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Affiliation(s)
- Svetlana N Morozkina
- Department of Natural Products Chemistry, Faculty of Chemistry, Saint-Petersburg State University, Universitetsky pr. 26, Petrodvorets 198504, Russia.
| | - Anna S Chentsova
- Department of Natural Products Chemistry, Faculty of Chemistry, Saint-Petersburg State University, Universitetsky pr. 26, Petrodvorets 198504, Russia
| | - Stanislav I Selivanov
- Department of Natural Products Chemistry, Faculty of Chemistry, Saint-Petersburg State University, Universitetsky pr. 26, Petrodvorets 198504, Russia
| | - Alexander G Shavva
- Department of Natural Products Chemistry, Faculty of Chemistry, Saint-Petersburg State University, Universitetsky pr. 26, Petrodvorets 198504, Russia
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5
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Synthesis and molecular structure study of 3-methoxy-7α-methyl-6-oxa-9β,14β-estra-1,3,5(10)-trien-17-one in solution. Chem Heterocycl Compd (N Y) 2012. [DOI: 10.1007/s10593-012-1048-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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6
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Characterization of the estradiol-binding site structure of human protein disulfide isomerase (PDI). PLoS One 2011; 6:e27185. [PMID: 22073283 PMCID: PMC3207843 DOI: 10.1371/journal.pone.0027185] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 10/12/2011] [Indexed: 11/29/2022] Open
Abstract
Background Earlier studies showed that 17β-estradiol (E2), an endogenous female sex hormone, can bind to human protein disulfide isomerase (PDI), a protein folding catalyst for disulfide bond formation and rearrangement. This binding interaction can modulate the intracellular levels of E2 and its biological actions. However, the structure of PDI's E2-binding site is still unclear at present, which is the focus of this study. Methodology/Principal Findings The E2-binding site structure of human PDI was studied by using various biochemical approaches coupled with radiometric receptor-binding assays, site-directed mutagenesis, and molecular computational modeling. Analysis of various PDI protein fragments showed that the [3H]E2-binding activity is not associated with the single b or b' domain but is associated with the b-b' domain combination. Computational docking analyses predicted that the E2-binding site is located in a hydrophobic pocket composed mainly of the b' domain and partially of the b domain. A hydrogen bond, formed between the 3-hydroxyl group of E2 and His256 of PDI is critical for the binding interaction. This binding model was jointly confirmed by a series of detailed experiments, including site-directed mutagenesis of the His256 residue coupled with selective modifications of the ligand structures to alter the binding interaction. Conclusions/Significance The results of this study elucidated the structural basis for the PDI–E2 binding interaction and the reservoir role of PDI in modulating the intracellular E2 levels. The identified PDI E2-binding site is quite different from its known peptide binding sites. Given that PDI is a potential therapeutic target for cancer chemotherapy and HIV prevention and that E2 can inhibit PDI activity in vitro, the E2-binding site structure of human PDI determined here offers structural insights which may aid in the rational design of novel PDI inhibitors.
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7
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Fu XM, Wang P, Zhu BT. Characterization of the estradiol-binding site structure of human pancreas-specific protein disulfide isomerase: indispensable role of the hydrogen bond between His278 and the estradiol 3-hydroxyl group. Biochemistry 2010; 50:106-15. [PMID: 21080683 DOI: 10.1021/bi101451g] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Estradiol (E(2)), a female sex hormone, has important biological functions. Human pancreas-specific protein disulfide isomerase (PDIp), a protein folding catalyst, was recently found to be able to bind E(2). Here we report the characterization of its E(2)-binding site by using biochemical methods coupled with molecular modeling tools. Analysis of various truncated PDIp proteins showed that the b-b' fragment contains an intact E(2)-binding site that has the same binding affinity as the full-length PDIp protein, with apparent K(d) values of approximately 170 nM. Computational modeling and docking analyses revealed that the E(2)-binding site in the b-b' fragment is located in a hydrophobic pocket composed mainly of the b' domain and partially of the b domain. The hydrogen bond, formed between the 3-hydroxyl group of E(2) (donor) and PDIp's His278 (acceptor), is indispensable for its binding. By contrast, the 17β-hydroxyl group of E(2) is of negligible importance for E(2) binding. This binding model was jointly confirmed by a series of experiments, such as selective mutation of the binding site amino acid residues and selective modification of the ligand structures.
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Affiliation(s)
- Xin-Miao Fu
- Department of Pharmacology, Toxicology and Therapeutics, School of Medicine, University of Kansas Medical Center, Kansas City, Kansas 66160, United States
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8
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Investigation of the conformational transformations in some 7α-methyl-6-oxa-14β-analogs of steroidal estrogens by NMR spectroscopy. Chem Heterocycl Compd (N Y) 2008. [DOI: 10.1007/s10593-008-0091-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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9
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Selivanov SI, Solov'ev AI, Morozkina SN, Shavva AG. An NMR study of the conformational mobility of steroid estrogen 7α-methyl-8α analogues. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2007; 33:324-31. [PMID: 17682388 DOI: 10.1134/s1068162007030053] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
All the signals in the 1H and 13C NMR spectra of some analogues of 7alpha-methyl-8alpha- and 6-oxa-8alpha-steroid estrogens were completely assigned. Considering the values of nuclear Overhauser effect and vicinal coupling constants, these steroids were shown to exhibit a fast, on the NMR time scale, conformational equilibrium arising due to the inversion of ring B. The conformer populations were obtained from a comparison of the experimental and theoretical values of the dihedral angles and the interproton distances. This conformational equilibrium was shown to depend on the nature of atom in position 6: for the 7alpha-methyl-6-oxa-8alpha analogues of the steroid estrogens, the population of the conformer with the pseudoaxial orientation of the 7alpha-methyl group was observed to be decreased compared with the 7alpha-methyl-8alpha analogue.
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10
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Zhu BT, Han GZ, Shim JY, Wen Y, Jiang XR. Quantitative structure-activity relationship of various endogenous estrogen metabolites for human estrogen receptor alpha and beta subtypes: Insights into the structural determinants favoring a differential subtype binding. Endocrinology 2006; 147:4132-50. [PMID: 16728493 DOI: 10.1210/en.2006-0113] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To search for endogenous estrogens that may have preferential binding affinity for human estrogen receptor (ER) alpha or beta subtype and also to gain insights into the structural determinants favoring differential subtype binding, we studied the binding affinities of 74 natural or synthetic estrogens, including more than 50 steroidal analogs of estradiol-17beta (E2) and estrone (E1) for human ER alpha and ER beta. Many of the endogenous estrogen metabolites retained varying degrees of similar binding affinity for ER alpha and ER beta, but some of them retained differential binding affinity for the two subtypes. For instance, several of the D-ring metabolites, such as 16 alpha-hydroxyestradiol (estriol), 16 beta-hydroxyestradiol-17 alpha, and 16-ketoestrone, had distinct preferential binding affinity for human ER beta over ER alpha (difference up to 18-fold). Notably, although E2 has nearly the highest and equal binding affinity for ER alpha and ER beta, E1 and 2-hydroxyestrone (two quantitatively predominant endogenous estrogens in nonpregnant woman) have preferential binding affinity for ER alpha over ER beta, whereas 16 alpha-hydroxyestradiol (estriol) and other D-ring metabolites (quantitatively predominant endogenous estrogens formed during pregnancy) have preferential binding affinity for ER beta over ER alpha. Hence, facile metabolic conversion of parent hormone E2 to various metabolites under different physiological conditions may serve unique functions by providing differential activation of the ER alpha or ER beta signaling system. Lastly, our computational three-dimensional quantitative structure-activity relationship/comparative molecular field analysis of 47 steroidal estrogen analogs for human ER alpha and ER beta yielded useful information on the structural features that determine the preferential activation of the ER alpha and ER beta subtypes, which may aid in the rational design of selective ligands for each human ER subtype.
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Affiliation(s)
- Bao Ting Zhu
- Department of Basic Pharmaceutical Sciences, College of Pharmacy, University of South Carolina, Basic Pharmaceutical Sciences, College of Pharmacy, 700 Sumter Street, Columbia, South Carolina 29209, USA.
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11
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Shavva AG, Selivanov SI, Starova GL, Abusalimov SN. Synthesis and investigation of the spatial arrangement of the 17β-acetoxy-7α,18-dimethyl-3-methoxy-6-oxaestra-1,3,5(10),8(9)-tetraene. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2006. [DOI: 10.1134/s1070428002120072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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12
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Cook CE, Kepler JA. 7α,11β-Dimethyl-19-nortestosterone: a potent and selective androgen response modulator with prostate-sparing properties. Bioorg Med Chem Lett 2005; 15:1213-6. [PMID: 15686944 DOI: 10.1016/j.bmcl.2004.11.076] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2004] [Revised: 11/23/2004] [Accepted: 11/30/2004] [Indexed: 10/26/2022]
Abstract
7alpha,11beta-Dimethyl-19-nortestosterone, made by 1,6-methyl addition to 17beta-acetoxy-11beta-methylestra-4,6-dien-3-one, was a highly potent and selective androgen response modulator, with enhanced androgen receptor binding, androgenic activity and anabolic:androgenic ratio over its two monomethyl homologs.
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Affiliation(s)
- C Edgar Cook
- Organic and Medicinal Chemistry, Science and Engineering Group, Research Triangle Institute, PO Box 12194, Research Triangle Park, NC 27709, USA.
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13
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Mekenya O, Kamenska V, Serafimova R, Poellinger L, Brouwer A, Walker J. Development and validation of an average mammalian estrogen receptor-based QSAR model. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2002; 13:579-595. [PMID: 12479373 DOI: 10.1080/1062936021000020044] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Development and evaluation of quantitative structure activity relationships (QSARs) for predicting estrogen receptor binding from chemical structure requires reliable algorithms for three-dimensional (3D) QSAR analysis and establishment of structurally diverse training sets of chemicals whose modes of action and measures of potency are well defined. One approach to selecting an appropriate training set is to minimize the biological variability in the model development, by using structurally restricted data sets. A second approach is to extend the structural diversity of chemicals at the cost of increased variability of biological assays. In this study, the second approach was used by organizing a training set of 151 chemicals with measured human alpha Estrogen Receptor (ERalpha), mouse uterine, rat uterine, and MCF7 cell Relative Binding Affinities (RBAs). The structurally augmented training set was submitted to a 3D pattern recognition analysis to derive a model for average mammalian ER binding affinity by employing the COmmon REactivity PAttern (COREPA) approach. Elucidation of this pattern required examination of the conformational flexibility of the compounds in an attempt to reveal areas in the multidimensional descriptor space, which are most populated by the conformers of the biologically active molecules and least populated by the inactive ones. The approach is not dependent upon a predetermined and specified toxicophore or an alignment of conformers to a lead compound. Reactivity patterns associated with mammalian ER binding affinity were obtained in terms of global nucleophilicity (E(HOMO)), interatomic distances between nucleophilic sites, and local nucleophilicity (charges or delocalizabilities) of those sites. Based on derived patterns, descriptor profiles were established for identifying and ranking compounds with RBA of > 150, 150-10, 10-1 and 1-0.1% relative to 17beta-estradiol. Specificity of reactivity profiles was found to increase gradually with increasing affinities associated with RBAs ranges under study. Using the results of this analysis, an exploratory expert system was developed for use in ranking relative mammalian ER binding affinity potential for large chemical data sets. The validity of the RBA predictions were confirmed by independent development and comparison with measured RBA values.
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Affiliation(s)
- O Mekenya
- Laboratory of Mathematical Chemistry, University As. Zlatarov, 8010 Bourgas, Bulgaria.
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14
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Dimitrov S, Breton R, Macdonald D, Walker JD, Mekenyan O. Quantitative prediction of biodegradability, metabolite distribution and toxicity of stable metabolites. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2002; 13:445-455. [PMID: 12184386 DOI: 10.1080/10629360290014313] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
An evaluation of the capability of organic chemicals to mineralize is an important factor to consider when assessing their fate in the environment. Microbial degradation can convert a toxic chemical into an innocuous one, and vice versa, or alter the toxicity of a chemical. Moreover, primary biodegradation can convert chemicals into stable products that can be difficult to mineralize. In this paper, we present some new results obtained on the basis of a recently developed probabilistic approach to modeling biodegradation based on microbial transformation pathways. The metabolic transformations and their hierarchy were calibrated by making use of the ready biodegradability data from the MITI-I test and expert knowledge for the most probable transformation pathways. A model was developed and integrated into an expert software system named CATABOL that is able to predict the probability of biodegradation of organic chemicals directly from their structure. CATABOL simulates the effects of microbial enzyme systems, generates the most plausible transformation pathways, and quantitatively predicts the persistence and toxicity of the biodegradation products. A subset of 300 organic chemicals were selected from Canada's Domestic Substances List and subjected to CATABOL to compare predicted properties of the parent chemicals with their respective first stable metabolite. The results show that most of the stable metabolites have a lower acute toxicity to fish and a lower bioaccumulation potential compared to the parent chemicals. In contrast, the metabolites appear to be generally more estrogenic than the parent chemicals.
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Affiliation(s)
- S Dimitrov
- Laboratory of Mathematical Chemistry, University Prof As. Zlatarov, Bourgas, Bulgaria
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15
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Anstead GM, Carlson KE, Katzenellenbogen JA. The estradiol pharmacophore: ligand structure-estrogen receptor binding affinity relationships and a model for the receptor binding site. Steroids 1997; 62:268-303. [PMID: 9071738 DOI: 10.1016/s0039-128x(96)00242-5] [Citation(s) in RCA: 482] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The accumulated knowledge on the binding of estradiol (E2) and its analogs and the results of affinity-labeling studies have been reviewed and are used herein to derive a binding site model for the estrogen receptor (ER). Estradiol is nonpolar and hydrophobic, except at its molecular termini. Most of its skeletal flexibility resides in the B-ring, and it probably binds in a low-energy conformation. The phenolic OH group in the A-ring contributes about 1.9 kcal/mol to the binding free energy and probably acts primarily as a hydrogen bond donor. The 17 beta-hydroxyl group in the D-ring contributes approximately 0.6 kcal/mol to the binding and probably acts as a hydrogen bond acceptor, either directly or via a water molecule. There also seems to be a degree of flexibility in the region of the receptor that encompasses the D-ring. The aromatic ring contributes about 1.5 kcal/mol, probably through weak polar interactions with receptor residues that contact the beta-face of the steroid. The receptor seems to surround the ligand, so that all four rings contribute significantly to binding. Small hydrophobic substituents enhance binding affinity at positions 4, 12 beta, 14, and 16 alpha; whereas, larger hydrophobic substituents are tolerated at positions 7 alpha, 11 beta, and 17 alpha. In general, the ER is intolerant of polar substituents. Based on E2 analogs bearing affinity-labeling groups, cysteine residues might be present in the binding site in the area of C-4, C-17 alpha, and C-17 beta, and a lysine residue might be located near C-16. Models that represent the limits of deformability of the ligand binding site, the position of preformed pockets, and space occupied by the receptor are presented. The various elements in this model for the binding of steroidal estrogens by the estrogen receptor are consistent with evidence emerging from the crystal structures of related nuclear hormone receptor ligand complexes.
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Affiliation(s)
- G M Anstead
- Department of Internal Medicine, University of Kentucky, Albert B. Chandler Medical Center, Lexington, USA
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16
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Wiese TE, Brooks SC. Molecular modeling of steroidal estrogens: novel conformations and their role in biological activity. J Steroid Biochem Mol Biol 1994; 50:61-73. [PMID: 8049135 DOI: 10.1016/0960-0760(94)90173-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Since the structure and conformation of many estrogenic ligands cannot be described with X-ray crystallographic studies, molecular modeling techniques must be used to generate their 3-dimensional structures. The potential of three molecular modeling methods to simulate the X-ray crystallographic geometry of estradiol-17 beta and various analogs (estratrien-1,17 beta-diol, estratrien-2,17 beta-diol, estratrien-3,11 alpha,17 beta-triol, estratrien-3,11 beta,17 beta-triol, 9 beta-estratrien-3,17 beta-diol-11-one) have been compared. MMP2 molecular mechanics as well as the MOPAC semi-empirical molecular orbital methods, AM1 and PM3, were examined in these studies of estrogens with unique ring distortions. Whereas all three methods were able to simulate reasonable estrogen structures, the MMP2 method was found to reproduce the X-ray geometry of estrogens better than the MOPAC methods. The contribution of crystal packing distortions on the X-ray structures in these comparisons is discussed. Additionally, a molecular modeling dynamics method for the systematic conformational searching of steroidal estrogens is presented. For each estrogen examined, conformational searching produced at least one unique steroid conformation in addition to the X-ray crystallographic geometry. The MMP2 potential energy of predicted conformations and transition barriers of these estrogens has been shown to be less than the free energy of receptor binding. Thus, it is conceivable that estrogen ligands which can exist in a number of conformations may be converted to a preferred geometry by binding within the specific site of receptor. Furthermore, it is suggested that conformational flexibility of estrogens may be an important property of specific ligands for the estrogen receptor.
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Affiliation(s)
- T E Wiese
- Department of Biochemistry, Wayne State University School of Medicine, Detroit, MI 48201
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17
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Napolitano E, Fiaschi R, Hanson RN. Estrogen receptor binding characteristics of 1,11 beta-ethanoestradiol: effect of a 1,11 beta-bridge on steroidal estrogen. J Steroid Biochem Mol Biol 1990; 37:295-300. [PMID: 2268562 DOI: 10.1016/0960-0760(90)90341-h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
As part of an ongoing program to develop high affinity estrogenic ligands we have synthesized the 11 beta-vinyl, 11 beta-ethyl- and 1,11 beta-ethanoestradiols. Because the 1,11 beta-ethano-estradiol had not been previously reported in the literature, the investigation of its receptor binding characteristics would provide valuable insight into the effect of 1/11 beta-substitution. The data obtained in this study indicate that although significant estrogen receptor affinity is present for the 1,11 beta-ethano derivative, the RBA values, 5-22.4%, were far less than those observed (5-300-fold less) for the corresponding 11 beta-ethyl and 11 beta-vinyl estradiols and less than those for the 1-methyl and 11 beta-methyl estradiols. These results suggest that the orientation that the 11 beta-substituent must occupy is directed away from the A-ring and that substituents in the 1-11 pocket produce a detrimental effect on receptor interactions.
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Affiliation(s)
- E Napolitano
- Section of Medicinal Chemistry, College of Pharmacy and Allied Health Professions, Northeastern University, Boston, MA 02115
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18
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Segaloff A, Gabbard RB. Structure-activity relationships of estrogens: effects of esterification of the 11 beta-hydroxyl group. Steroids 1984; 43:111-23. [PMID: 6523530 DOI: 10.1016/0039-128x(84)90063-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Fourteen esters (formate, acetate, propionate, butyrate, hexanoate, heptanoate, and benzoate) located at C-11 of 11 beta-hydroxyesterone and 11 beta-hydroxyestradiol-17 beta were synthesized and evaluated for uterotropic and gonadotropin release inhibition in rats, as well as their ability to displace (3H) estradiol-17 beta from the rat uterine cytosolic estrogen receptor. The most potent uterotropic agent was 11 beta-formoxyestrone which was 1,625 or 2,500 times as active as 11 beta-hydroxyesterone in the uterotropic or gonadotropin release inhibition assay, respectively. 11 beta-Formoxyestrone was 7.5 times as uterotropic as estradiol-17 beta and equal to estradiol-17 beta in inhibiting gonadotropin release. However, the most potent inhibitor of gonadotropin release was 11 beta-acetoxy-estradiol-17 beta which had 133% of the activity of estradiol-17 beta, although it had only 38% of the activity of estradiol-17 beta in the uterotropic assay. Esters larger than the acetoxy group showed sharply decreased activities in either assay. Despite the high estrogenic potency of the 11-formates or 11-acetates, they were rather weak (6% to 35% as active as estradiol-17 beta) in displacing (3H) estradiol-17 beta from the rat uterine cytosolic estrogen receptor.
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19
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Abstract
The 9 beta isomers of estradiol-17 beta, estradiol-17 a estrone and 17-ethinylestradiol-17 beta were synthesized and compared with their 9a-counterparts in the rat uterine cytosol estrogen receptor, uterotropic, and gonadotropin release inhibition assays. Except for 17-ethinyl-9 beta-estradiol-17 beta which was as active as its 9a isomer in the uterotropic assay, none of the 9 beta estrogens exhibited any biological activity which was equal to or greater than their 9a counterparts. For examples, 9 beta-estradiol-17 beta was 1/10 as active as estradiol-17 beta, and 9 beta-estrone was 1/4 as active as estrone in the uterotropic assay.
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