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Mills SJ, Rossi AM, Konieczny V, Bakowski D, Taylor CW, Potter BVL. d- chiro-Inositol Ribophostin: A Highly Potent Agonist of d- myo-Inositol 1,4,5-Trisphosphate Receptors: Synthesis and Biological Activities. J Med Chem 2020; 63:3238-3251. [PMID: 32052631 PMCID: PMC7104261 DOI: 10.1021/acs.jmedchem.9b01986] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Analogues
of the Ca2+-releasing intracellular messenger d-myo-inositol 1,4,5-trisphosphate [1, Ins(1,4,5)P3] are important synthetic targets. Replacement
of the α-glucopyranosyl motif in the natural product mimic adenophostin 2 by d-chiro-inositol in d-chiro-inositol adenophostin 4 increased
the potency. Similar modification of the non-nucleotide Ins(1,4,5)P3 mimic ribophostin 6 may increase the activity. d-chiro-Inositol ribophostin 10 was synthesized by coupling as building blocks suitably protected
ribose 12 with l-(+)-3-O-trifluoromethylsulfonyl-6-O-p-methoxybenzyl-1,2:4,5-di-O-isopropylidene-myo-inositol 11. Separable
diastereoisomeric 3-O-camphanate esters of (±)-6-O-p-methoxy-benzyl-1,2:4,5-di-O-isopropylidene-myo-inositol allowed the preparation
of 11. Selective trans-isopropylidene
deprotection in coupled 13, then monobenzylation gave
separable regioisomers 15 and 16. p-Methoxybenzyl group deprotection of 16, phosphitylation/oxidation,
then deprotection afforded 10, which was a full agonist
in Ca2+-release assays; its potency and binding affinity
for Ins(1,4,5)P3R were similar to those of adenophostin.
Both 4 and 10 elicited a store-operated
Ca2+ current ICRAC in patch-clamped cells, unlike
Ins(1,4,5)P3 consistent with resistance to metabolism. d-chiro-Inositol ribophostin is the most potent
small-molecule Ins(1,4,5)P3 receptor agonist without a
nucleobase yet synthesized.
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Affiliation(s)
- Stephen J Mills
- Drug Discovery & Medicinal Chemistry, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Ana M Rossi
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Vera Konieczny
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Daniel Bakowski
- Centre of Integrative Physiology, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Colin W Taylor
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Barry V L Potter
- Drug Discovery & Medicinal Chemistry, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
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Thorsheim K, Siegbahn A, Johnsson RE, Stålbrand H, Manner S, Widmalm G, Ellervik U. Chemistry of xylopyranosides. Carbohydr Res 2015; 418:65-88. [PMID: 26580709 DOI: 10.1016/j.carres.2015.10.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 10/09/2015] [Accepted: 10/10/2015] [Indexed: 12/22/2022]
Abstract
Xylose is one of the few monosaccharidic building blocks that are used by mammalian cells. In comparison with other monosaccharides, xylose is rather unusual and, so far, only found in two different mammalian structures, i.e. in the Notch receptor and as the linker between protein and glycosaminoglycan (GAG) chains in proteoglycans. Interestingly, simple soluble xylopyranosides can not only initiate the biosynthesis of soluble GAG chains but also function as inhibitors of important enzymes in the biosynthesis of proteoglycans. Furthermore, xylose is a major constituent of hemicellulosic xylans and thus one of the most abundant carbohydrates on Earth. Altogether, this has spurred a strong interest in xylose chemistry. The scope of this review is to describe synthesis of xylopyranosyl donors, as well as protective group chemistry, modifications, and conformational analysis of xylose.
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Affiliation(s)
- Karin Thorsheim
- Centre for Analysis and Synthesis, Centre for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Anna Siegbahn
- Centre for Analysis and Synthesis, Centre for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Richard E Johnsson
- Centre for Analysis and Synthesis, Centre for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Henrik Stålbrand
- Centre for Molecular Protein Science, Centre for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Sophie Manner
- Centre for Analysis and Synthesis, Centre for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Göran Widmalm
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ulf Ellervik
- Centre for Analysis and Synthesis, Centre for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
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3
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Sureshan KM, Riley AM, Thomas MP, Tovey SC, Taylor CW, Potter BVL. Contribution of phosphates and adenine to the potency of adenophostins at the IP₃ receptor: synthesis of all possible bisphosphates of adenophostin A. J Med Chem 2012; 55:1706-20. [PMID: 22248345 PMCID: PMC3285137 DOI: 10.1021/jm201571p] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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Although adenophostin A (AdA), the most potent agonist
of d-myo-inositol 1,4,5-trisphosphate receptors
(IP3R), is thought to mimic IP3, the relative
roles
of the different phosphate groups and the adenosine motif have not
been established. We synthesized all three possible bisphosphate analogues
of AdA and glucose 3,4-bisphosphate (7, AdA lacking the
2′-AMP). 2′-Dephospho-AdA (6) was prepared
via a novel regioselective dephosphorylation strategy. Assessment
of the abilities of these bisphosphates to stimulate intracellular
Ca2+ release using recombinant rat type 1 IP3R (IP3R1) revealed that 6, a mimic of Ins(4,5)P2, is only 4-fold less potent than IP3, while 7 is some 400-fold weaker and even 3″-dephospho-AdA
(5) is measurably active, despite missing one of the
vicinal bisphosphate groups normally thought to be crucial for IP3-like activity. Compound 6 is the most potent
bisphosphate yet discovered with activity at IP3R. Thus,
adenosine has a direct role independent of the 2′-phosphate
group in contributing toward the potency of adenophostins, the vicinal
bisphosphate motif is not essential for activity at the IP3R, as always thought, and it is possible to design potent agonists
with just two of the three phosphates. A model with a possible adenine–R504
interaction supports the activity of 5 and 6 and also allows a reappraisal of the unexpected activity previously
reported for the AdA regioisomer 2″-phospho-3″-dephospho-AdA 40.
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Affiliation(s)
- Kana M Sureshan
- Wolfson Laboratory of Medicinal Chemistry, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
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4
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Polavarapu PL, Frelek J, Woźnica M. Determination of the absolute configurations using electronic and vibrational circular dichroism measurements and quantum chemical calculations. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.tetasy.2011.09.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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5
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Bowen EG, Wardrop DJ. Diastereoselective nitrenium ion-mediated cyclofunctionalization: total synthesis of (+)-castanospermine. Org Lett 2010; 12:5330-3. [PMID: 20964285 DOI: 10.1021/ol102371x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The asymmetric total synthesis of the α-glucosidase inhibitor (+)-castanospermine is reported. The central theme in our approach to this polyhydroxylated alkaloid is the simultaneous generation of the piperidine ring and the C-1/8a erythro stereodiad through the diastereoselective, oxamidation of an unsaturated O-alkyl hydroxamate. This process is believed to proceed sequentially via singlet acylnitrenium and aziridinium ion intermediates.
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Affiliation(s)
- Edward G Bowen
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, United States
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6
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Rossi AM, Riley AM, Potter BV, Taylor CW. Adenophostins. CURRENT TOPICS IN MEMBRANES 2010; 66:209-33. [DOI: 10.1016/s1063-5823(10)66010-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
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7
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Benito D, Isabel Matheu M, Morère A, Díaz Y, Castillón S. Designing an effective approach for obtaining methylenecarboxylate analogues of adenophostin A. Preliminary results. Carbohydr Res 2009; 344:2559-67. [DOI: 10.1016/j.carres.2009.09.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 09/16/2009] [Accepted: 09/27/2009] [Indexed: 11/29/2022]
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8
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A new stereoselective approach to a selectively protected derivative of d-pinitol and its evaluation as α-l-rhamnopyranose mimetic. Tetrahedron Lett 2008. [DOI: 10.1016/j.tetlet.2008.05.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Utille JP, Jeacomine I. Synthesis of a library of allyl α-l-arabinofuranosyl-α- or β-d-xylopyranosides; route to higher oligomers. Carbohydr Res 2007; 342:2649-56. [PMID: 17904112 DOI: 10.1016/j.carres.2007.08.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Revised: 07/08/2007] [Accepted: 08/17/2007] [Indexed: 10/22/2022]
Abstract
Six isomeric disaccharides allyl 2,3,5-tri-O-benzoyl-alpha-l-arabinofuranosyl-alpha-d-xylopyranosides and beta-d-xylopyranosides were synthetized by the stereoselective glycosylation of pure allyl alpha- or beta-d-xylopyranosides with 1-O-acetyl-2,3,5-tri-O-benzoyl-l-arabinofuranose as donor, catalyzed with BF(3).Et(2)O in DCM. Regio- and stereoselective glycosylation with excess of donor furnished almost exclusively the trisaccharides allyl 2,3-di-O-(2,3,5-tri-O-benzoyl-alpha-l-arabinofuranosyl)-alpha- or beta-d-xylopyranosides. Extension of the reaction to the triol beta-d-xylopyranosyl-(1-->4)-1,2,3-tri-O-acetyl-alpha-d-xylopyranose, obtained from the 4-hydroxyl penta-O-acetyl-alpha-xylobiose, gave in the same manner the tetrasaccharide [2,3-di-O-(2,3,5-tri-O-benzoyl-alpha-l-arabinofuranosyl)-beta-d-xylopyranosyl]-(1-->4)-1,2,3-tri-O-acetyl-alpha-d-xylopyranose. The protocol described herein should offer the possibility to produce branched oligosaccharides with a 2,3-di-O-(alpha-l-Ara(f))-beta-d-Xyl(p) block unit at the terminal non-reducing end.
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Affiliation(s)
- Jean-Pierre Utille
- Centre de Recherches sur les Macromolécules Végétales (CERMAV-CNRS), BP53, 38041 Grenoble cedex 9, France.
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10
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Abstract
The inositol 1,4,5-trisphosphate (InsP3) receptors (InsP3Rs) are a family of Ca2+ release channels localized predominately in the endoplasmic reticulum of all cell types. They function to release Ca2+ into the cytoplasm in response to InsP3 produced by diverse stimuli, generating complex local and global Ca2+ signals that regulate numerous cell physiological processes ranging from gene transcription to secretion to learning and memory. The InsP3R is a calcium-selective cation channel whose gating is regulated not only by InsP3, but by other ligands as well, in particular cytoplasmic Ca2+. Over the last decade, detailed quantitative studies of InsP3R channel function and its regulation by ligands and interacting proteins have provided new insights into a remarkable richness of channel regulation and of the structural aspects that underlie signal transduction and permeation. Here, we focus on these developments and review and synthesize the literature regarding the structure and single-channel properties of the InsP3R.
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Affiliation(s)
- J Kevin Foskett
- Department of Physiology, University of Pennsylvania, Philadelphia 19104-6085, USA.
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11
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Poinas A, Backers K, Riley AM, Mills SJ, Moreau C, Potter BVL, Erneux C. Interaction of the catalytic domain of inositol 1,4,5-trisphosphate 3-kinase A with inositol phosphate analogues. Chembiochem 2005; 6:1449-57. [PMID: 15997461 DOI: 10.1002/cbic.200400443] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The levels of inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] in the cytoplasm are tightly regulated by two enzymes, Ins(1,4,5)P3 3-kinase and type I Ins(1,4,5)P3 5-phosphatase. The catalytic domain of Ins(1,4,5)P3 3-kinase (isoenzymes A, B and C) is restricted to approximately 275 amino acids at the C-terminal end. We were interested in understanding the catalytic mechanism of this key family of enzymes in order to exploit this in inhibitor design. We expressed the catalytic domain of rat Ins(1,4,5)P3 3-kinase A in Escherichia coli as a His- and S-tagged fusion protein. The purified enzyme was used in an Ins(1,4,5)P3 kinase assay to phosphorylate a series of inositol phosphate analogues with three or four phosphate groups. A synthetic route to D-2-deoxy-Ins(1,4,5)P3 was devised. D-2-Deoxy-Ins(1,4,5)P3 and D-3-deoxy-Ins(1,4,6)P3 were potent inhibitors of the enzyme, with IC50 values in the micromolar range. Amongst all analogues tested, only D-2-deoxy-Ins(1,4,5)P3 appears to be a good substrate of the Ins(1,4,5)P3 3-kinase. Therefore, the axial 2-hydroxy group of Ins(1,4,5)P3 is not involved in recognition of the substrate nor does it participate in the phosphorylation mechanism of Ins(1,4,5)P3. In contrast, the equatorial 3-hydroxy function must be present in that configuration for phosphorylation to occur. Our data indicate the importance of the 3-hydroxy function in the mechanism of inositol trisphosphate phosphorylation rather than in substrate binding.
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Affiliation(s)
- Alexandra Poinas
- Interdisciplinary Research Institute (IRIBHM), Université Libre de Bruxelles, Campus Erasme, Bldg C, 808 Route de Lennik, 1070 Brussels, Belgium
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12
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Chrétien F, Roussel F, Hilly M, Mauger J, Chapleur Y. New Sugar‐Based Permeant Analogs of D‐ Myo ‐Inositol 1,4,5‐Trisphosphate Mimicking the Effect of Vasopressin: Synthesis and Biologic Evaluation*. J Carbohydr Chem 2005. [DOI: 10.1081/car-200068070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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13
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Terauchi M, Yahiro Y, Abe H, Ichikawa S, Tovey SC, Dedos SG, Taylor CW, Potter BV, Matsuda A, Shuto S. Synthesis of 4,8-anhydro-d-glycero-d-ido-nonanitol 1,6,7-trisphosphate as a novel IP3 receptor ligand using a stereoselective radical cyclization reaction based on a conformational restriction strategy. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.02.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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14
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Park S, Lee MR, Pyo SJ, Shin I. Carbohydrate chips for studying high-throughput carbohydrate-protein interactions. J Am Chem Soc 2004; 126:4812-9. [PMID: 15080685 DOI: 10.1021/ja0391661] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Carbohydrate-protein interactions play important biological roles in living organisms. For the most part, biophysical and biochemical methods have been used for studying these biomolecular interactions. Less attention has been given to the development of high-throughput methods to elucidate recognition events between carbohydrates and proteins. In the current effort to develop a novel high-throughput tool for monitoring carbohydrate-protein interactions, we prepared carbohydrate microarrays by immobilizing maleimide-linked carbohydrates on thiol-derivatized glass slides and carried out lectin binding experiments by using these microarrays. The results showed that carbohydrates with different structural features selectively bound to the corresponding lectins with relative binding affinities that correlated with those obtained from solution-based assays. In addition, binding affinities of lectins to carbohydrates were also quantitatively analyzed by determining IC(50) values of soluble carbohydrates with the carbohydrate microarrays. To fabricate carbohydrate chips that contained more diverse carbohydrate probes, solution-phase parallel and enzymatic glycosylations were performed. Three model disaccharides were in parallel synthesized in solution-phase and used as carbohydrate probes for the fabrication of carbohydrate chips. Three enzymatic glycosylations on glass slides were consecutively performed to generate carbohydrate microarrays that contained the complex oligosaccharide, sialyl Le(x). Overall, these works demonstrated that carbohydrate chips could be efficiently prepared by covalent immobilization of maleimide-linked carbohydrates on the thiol-coated glass slides and applied for the high-throughput analyses of carbohydrate-protein interactions.
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Affiliation(s)
- Sungjin Park
- Department of Chemistry, Yonsei University, Seoul 120-749, Korea
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15
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Dozol H, Maechling C, Graff R, Matsuda A, Shuto S, Spiess B. Conformational and inframolecular studies of the protonation of adenophostin analogues lacking the adenine moiety. Biochim Biophys Acta Gen Subj 2004; 1671:1-8. [PMID: 15026139 DOI: 10.1016/j.bbagen.2003.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2003] [Revised: 12/10/2003] [Accepted: 12/10/2003] [Indexed: 10/26/2022]
Abstract
Four adenophostin analogues lacking the adenine moiety were subjected to 31P- and 1H-NMR titrations in order to determine the acid-base behaviour of the individual ionisable groups of the molecules and the complex interplay of intramolecular interactions resulting from the protonation process. For the two trisphosphorylated compounds, the curve pattern of the phosphorus nuclei corresponds to the superimposition of the titration curves of a monophosphorylated polyol and a polyol carrying two vicinal phosphates, suggesting that the two phosphate moieties behave independently. Also, the general shape of 1H-NMR titration curves of the studied compounds is very close to that of adenophostin A, indicating that the adenine moiety does not specifically interact with the phosphorylated sugar moieties. The curves show, however, that both trisphosphorylated compounds adopt slightly different preferential conformations which could contribute to explain the difference in their affinity for Ins(1,4,5)P3 receptor. Their macroscopic as well as the microscopic protonation constants are higher than those of adenophostin A, indicating that the adenine moiety plays a base-weakening effect on the phosphate groups. Further analysis of the microscopic protonation constants confirms that the compound whose conformation is the closest to that of adenophostin A also shows the highest biological activity. The two bisphosphorylated analogues studied behave very similarly, suggesting that the deletion of the hydroxymethyl group on the pentafuranosyl ring only weakly influences the protonation process of the phosphate groups that bear the glucopyranose moiety.
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Affiliation(s)
- Hélène Dozol
- Laboratoire de Pharmacochimie Moléculaire, UMR 7081 du CNRS, Faculté de Pharmacie, ULP, 74, route du Rhin, B.P. 24, 67401 Illkirch, France
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16
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Rosenberg HJ, Riley AM, Laude AJ, Taylor CW, Potter BVL. Synthesis and Ca2+-Mobilizing Activity of Purine-Modified Mimics of Adenophostin A: A Model for the Adenophostin−Ins(1,4,5)P3Receptor Interaction. J Med Chem 2003; 46:4860-71. [PMID: 14584937 DOI: 10.1021/jm030883f] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthesis of a series of adenophostin A analogues modified at C-6 and C-2 of adenine is described. The target compounds were synthesized by a convergent route involving a modified Vorbrüggen condensation of either 6-chloropurine or 2,6-dichloropurine with a protected disaccharide, yielding two versatile intermediates capable of undergoing substitution with a range of nucleophiles. The new analogues showed a range of abilities to mobilize Ca(2+) from the intracellular stores of permeabilized hepatocytes and are among the first totally synthetic compounds to approach the activity of adenophostin A. In agreement with the biological results, docking studies of adenophostin A using the recently reported X-ray crystal structure of the type 1 Ins(1,4,5)P(3) receptor binding core suggested that, in likely binding modes of adenophostin A, the area around N(6) may be relatively open, identifying this region of the adenophostin A molecule as a promising target for further elaboration. The docking results also point to specific interactions involving residues within the binding domain of the Ins(1,4,5)P(3) receptor that may be involved in the molecular recognition of the adenophostins.
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Affiliation(s)
- Heidi J Rosenberg
- Wolfson Laboratory of Medicinal Chemistry, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
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17
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Abstract
The adenophostins exhibit approximately 10-100 times higher receptor binding and Ca2+ mobilising potencies in comparison with the natural second messenger D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3]. Despite many synthetic attempts to determine the minimal structural requirement for this unusual behaviour of the adenophostins, few related simplified analogues displaying higher activity than that of Ins(1,4,5)P3 have been reported. However, biological evaluation of such analogues has revealed that one of the key factors for the enhanced biological activity is the adenine moiety. To further understand the effect that the adenine base has upon the activity of the adenophostins, congeners in which this functionality is replaced by uracil, benzimidazole, 2-methoxynaphthalene, 4-methylanisole and 4-methylnaphthalene using the common intermediate 1,2-di-O-acetyl-5-O-benzyl-3-O-(3,4-di-O-acetyl-2,6-di-O-benzyl-alpha-D-glucopyranosyl)-ribofuranose have been synthesised using a base replacement strategy. The synthesis of the uracil and benzimidazole analogues was achieved using the Vorbrüggen condensation procedure. The 1'-C-glycosidic analogues were prepared using Friedel-Crafts type C-aryl glycosidation reactions. Phosphate groups were introduced using the phosphoramidite method with subsequent removal of all-benzyl protecting groups by catalytic hydrogenation or catalytic hydrogen transfer. Apart from one analogue with an alpha-glycosidic linkage all compounds were more potent than Ins(1,4,5)P3 and most tended more towards adenophostin in activity. These analogues will be valuable tools to unravel the role that the adenine moiety plays in the potent activity of the adenophostins and demonstrate that this strategy is effective at producing highly potent ligands.
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Affiliation(s)
- S Shuto
- Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, UK
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18
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Correa V, Riley AM, Shuto S, Horne G, Nerou EP, Marwood RD, Potter BV, Taylor CW. Structural determinants of adenophostin A activity at inositol trisphosphate receptors. Mol Pharmacol 2001; 59:1206-15. [PMID: 11306705 DOI: 10.1124/mol.59.5.1206] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Adenophostin A is the most potent known agonist of inositol 1,4,5-trisphosphate (InsP(3)) receptors. Ca(2+) release from permeabilized hepatocytes was 9.9 +/- 1.6-fold more sensitive to adenophostin A (EC(50), 14.7 +/- 2.4 nM) than to InsP(3) (145 +/- 10 nM), consistent with the greater affinity of adenophostin A for hepatic InsP(3) receptors (K(d) = 0.48 +/- 0.06 and 3.09 +/- 0.33 nM, respectively). Here, we systematically modify the structures of the glucose, ribose, and adenine moieties of adenophostin A and use Ca(2+) release and binding assays to define their contributions to high-affinity binding. Progressive trimming of the adenine of adenophostin A reduced potency, but it fell below that of InsP(3) only after complete removal of the adenine. Even after substantial modifications of the adenine (to uracil or even unrelated aromatic rings, retaining the beta-orientation), the analogs were more potent than InsP(3). The only analog with an alpha-ribosyl linkage had massively decreased potency. The 2'-phosphate on the ribose ring of adenophostin A was essential and optimally active when present on a five-membered ring in a position stereochemically equivalent to its location in adenophostin A. Xylo-adenophostin, where xylose replaces the glucose ring of adenophostin A, was only slightly less potent than adenophostin A, whereas manno-adenophostin (mannose replacing glucose) had similar potency to InsP(3). These results are consistent with the relatively minor role of the 3-hydroxyl of InsP(3) (the equivalent is absent from xylo-adenophostin) and greater role of the equatorial 6-hydroxyl (the equivalent is axial in manno-adenophostin). This is the first comprehensive analysis of all the key structural elements of adenophostin A, and it provides a working model for the design of related high-affinity ligands of InsP(3) receptors.
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Affiliation(s)
- V Correa
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1QJ, United Kingdom
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