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Ghosh N, Kundu LM. Cyclic di-peptide in situ inhibited protein-aggregation. Bioorg Med Chem Lett 2023; 91:129379. [PMID: 37331639 DOI: 10.1016/j.bmcl.2023.129379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 06/10/2023] [Accepted: 06/12/2023] [Indexed: 06/20/2023]
Abstract
An increasing number of neurodegenerative diseases seem to be associated with protein misfolding that often leads to misfolded protein aggregates with a β-sheet conformation and accumulation in the brain which directly contributes to or modulates the associated pathology. Protein aggregation diseases like Huntington's disease results from the deposition of aggregated huntingtin proteins within the nucleus, transmissible prion encephalopathies occur due to extracellular deposition of pathogenic prion proteins whereas Alzheimer's disease from the accumulation of both extracellular β-amyloid and intracellular hyperphosphorylated tau protein aggregates. In the generalized purpose, we have taken the core sequence of amyloid-β (responsible for its aggregation) as the aggregating peptide (AP). Among the various emerging therapeutic approaches against aggregation-related degenerative diseases such as diminishing the monomeric precursor protein, inhibiting aggregation, or blocking aggregation-induced cellular toxicity pathways, we focussed on the strategy based on the inhibition of protein aggregation using rationally designed peptide inhibitors comprising both the recognition and β-breaking component in the sequence. The "O → N acyl migration" concept was used to form cyclic peptide in situ for the generation of a bent unit which may act as disruption moiety for the inhibition process. The kinetics of aggregation was characterized by various biophysical tools (ThT-assay, TEM, CD, and FTIR). Results implied that the designed inhibitor peptides (IP) might be valuable to inhibit all the related aggregated peptides.
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Affiliation(s)
- Nibedita Ghosh
- Centre for the Environment, IIT Guwahati, Assam 781039, India; Symbol Discovery Ltd, Hyderabad 500046, India.
| | - Lal Mohan Kundu
- Centre for the Environment, IIT Guwahati, Assam 781039, India; Department of Chemistry, Indian Institute of Technology Guwahati, 781039, India
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2
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Chua N, Wong YH, El Sahili A, Liu CF, Lescar J. On the design of a constitutively active peptide asparaginyl ligase for facile protein conjugation. FEBS Open Bio 2023. [PMID: 36788723 DOI: 10.1002/2211-5463.13575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 01/24/2023] [Accepted: 02/13/2023] [Indexed: 02/16/2023] Open
Abstract
Peptide asparaginyl ligases (PALs) are precision tools for peptide cyclization, cell-surface labelling, protein semi-synthesis and protein conjugation. PALs are expressed as inactive proenzymes requiring low pH activation. During activation, a large portion of the cap domain of the proenzyme that covers the substrate binding site is proteolytically removed, exposing the active site to solvent and releasing a population of heterogenous active enzymes. The availability of a readily active ligase not requiring acid-activation and subsequent purification of active forms would facilitate manufacturing and streamline applications. Here, we engineered the OaAEP1b-C247A hyperactive ligase via serial truncations along the linker connecting the cap and core domain of the proenzyme. Recombinant expression of the truncated constructs was carried out in E. coli. Following a solubilization/refolding protocol, one truncated construct termed "OaAEP1b-C247A-𝚫351" could be overexpressed in the insoluble fraction, purified, and displayed a level of ligase activity comparable to the acid-activated OaAEP1b-C247A enzyme. This constitutively active protein can be stored for up to two years at -80°C and readily used for peptide cyclization and protein conjugation. We were able to express and purify a stable constitutively active asparaginyl ligase that can be stored for months without significant activity loss. The removal of the low pH proenzyme activation step eliminates the heterogeneity introduced by this procedure. The yield of purified recombinant active ligase that can be routinely obtained per 100 millilitres of E. coli cell culture is about 0.9 mg. This recombinant active ligase can be used to carry out protein conjugation.
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Affiliation(s)
- Niying Chua
- School of Biological Sciences, Nanyang Technological University. 60 Nanyang Drive, Singapore, 637551.,NTU Institute of Structural Biology, Experimental Medicine Building, 59 Nanyang Drive, Singapore, 636921
| | - Yee Hwa Wong
- School of Biological Sciences, Nanyang Technological University. 60 Nanyang Drive, Singapore, 637551.,NTU Institute of Structural Biology, Experimental Medicine Building, 59 Nanyang Drive, Singapore, 636921
| | - Abbas El Sahili
- School of Biological Sciences, Nanyang Technological University. 60 Nanyang Drive, Singapore, 637551.,NTU Institute of Structural Biology, Experimental Medicine Building, 59 Nanyang Drive, Singapore, 636921
| | - Chuan Fa Liu
- School of Biological Sciences, Nanyang Technological University. 60 Nanyang Drive, Singapore, 637551
| | - Julien Lescar
- School of Biological Sciences, Nanyang Technological University. 60 Nanyang Drive, Singapore, 637551.,NTU Institute of Structural Biology, Experimental Medicine Building, 59 Nanyang Drive, Singapore, 636921
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Gless BH, Olsen CA. On-Resin Peptide Cyclization Using the 3-Amino-4-(Methylamino)Benzoic Acid MeDbz Linker. Methods Mol Biol 2022; 2371:101-115. [PMID: 34596845 DOI: 10.1007/978-1-0716-1689-5_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Cyclic peptides are becoming increasingly important in drug discovery due to their specific binding properties, larger surface area compared to small molecules, and their ready and modular synthetic accessibility. In this protocol, we describe an on-resin, cleavage-inducing cyclization methodology for the synthesis of cyclic thiodepsipeptides and cyclic homodetic peptides using the 3-amino-4-(methylamino)benzoic acid (MeDbz) linker. We further describe three post-cyclization one-pot procedures, which include desulfurization, disulfide bond formation, and S-alkylation of cysteine residues.
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Affiliation(s)
- Bengt H Gless
- Center for Biopharmaceuticals and Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christian A Olsen
- Center for Biopharmaceuticals and Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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Wang J, Li X. Complex cyclic peptide synthesis via serine/threonine ligation chemistry. Bioorg Med Chem Lett 2021; 54:128430. [PMID: 34757215 DOI: 10.1016/j.bmcl.2021.128430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 10/18/2021] [Accepted: 10/21/2021] [Indexed: 11/21/2022]
Abstract
Non-ribosomal cyclic peptides are abundant in natural sources, exhibiting attractive bioactivities and favorable pharmacological properties. Furthermore, their structural complexity renders them as attractive synthetic targets. A general task for cyclic peptide synthesis is the peptide cyclization. Compared to the traditional dehydration-based peptide macrolactamization, chemoselective peptide ligation provides an alternative, sometimes advantageous, strategy to cyclize peptides. Herein, we provide a series of structurally complex cyclic peptide examples whose total syntheses were achieved via peptide ligation-mediated peptide cyclization. The special features of these strategies for achieving the total synthesis are highlighted.
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Vasco AV, Ricardo MG, Rivera DG, Wessjohann LA. Ligation, Macrocyclization, and Simultaneous Functionalization of Peptides by Multicomponent Reactions (MCR). Methods Mol Biol 2022; 2371:143-57. [PMID: 34596847 DOI: 10.1007/978-1-0716-1689-5_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Multicomponent reactions (MCRs) are recently expanding the plethora of solid-phase protocols for the synthesis and derivatization of peptides. Herein, we describe a solid-phase-compatible strategy based on MCRs as a powerful strategy for peptide cyclization and ligation . We illustrate, using Gramicidin S as a model peptide, how the execution of on-resin Ugi reactions enables the simultaneous backbone N-functionalization and cyclization, which are important types of derivatizations in peptide-based drug development or for incorporation of conjugation handles, or labels.
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Zhang W, Liu J, Zhang C, Yu X, Zhong B. Structural definition of the discrete hotspot sites of BMP-2 conformational wrist epitope and rational design of the hotspot-derived osteogenic peptides against chondrocyte senescence. Bioorg Chem 2021; 116:105382. [PMID: 34598087 DOI: 10.1016/j.bioorg.2021.105382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 09/10/2021] [Accepted: 09/20/2021] [Indexed: 01/05/2023]
Abstract
The bone morphogenetic protein-2 (BMP-2) is an essential regulator of bone formation and remodeling, which has also been implicated in the pathogenesis of osteoarthritis and its closely related chondrocyte senescence. The BMP-2 uses a conformational wrist epitope and a linear knuckle epitope to interact with type-I (BMPR-I) and type-II (BMPR-II) receptors, respectively. Previously, the knuckle epitope has been intensely studied, but the wrist epitope still remains largely unexplored due to its discontinuous nature. In the present work, the intermolecular interaction of BMP-2 with BMPR-I was investigated systematically at structural, energetic and dynamic levels. Three discrete hotspots that represent the key BMPR-I recognition sites of BMP-2 were identified; they are spatially dispersed over the two monomers of BMP-2 dimer and totally account for 83.5 % binding potency of BMP-2 to BMPR-I (hotspot 1: residues 49-70 in monomer 1; hotspot 2: residues 24-31 in monomer 2; hotspot 3: residues 88-107 in monomer 2). Therefore, we defined the three discrete hotspot sites as the core region of wrist epitope; their contribution to the binding increases in the order: hotspot 2 < hotspot 3 < hotspot 1. We demonstrated that the primary hotspot 1 site has a native U-shaped conformation in the full-length BMP-2 protein context, but it cannot maintain in the native conformation when split from the context to obtain a free hotspot-1 peptide, thus largely impairing its binding potency to BMPR-I. We further employed disulfide-bonded cyclization and head-to-tail cyclization to constrain the peptide conformation, and found that only the former can effectively constrain the peptide into native conformation, thus considerably improving its binding affinity to BMPR-I, whereas the latter totally disorders the native conformation, thus rendering the peptide as a full nonbinder of BMPR-I.
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Ghosh N, Kundu LM. In-situ side-chain peptide cyclization as a breaker strategy against the amyloid aggregating peptide. Bioorg Med Chem 2021; 33:116017. [PMID: 33486160 DOI: 10.1016/j.bmc.2021.116017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 01/07/2021] [Accepted: 01/08/2021] [Indexed: 02/07/2023]
Abstract
Accumulation and deposition of misfolded amyloid β (Aβ) peptide outside the nerve cells are one of the major causes of Alzheimer's disease (AD). To date, one of the promising therapeutic strategies for AD is to block the early steps associated with the aggregation of Aβ peptide. We have developed synthetic breaker peptides derived from the original Aβ sequences that undergo self-cyclization in situ. We have focussed and replaced Val-18 (of Aβ) by side-chain modified glutamic acid (Glu-OBn) to generate adequate turn through in-situ peptide cyclization to disrupt the β-sheet structure of Aβ. The disruption of amyloid fibril formation and the mechanism of the 'inhibition of aggregation' were studied by various biophysical methods, such as ThT-assay, TEM, Congo-red birefringence study. CD and FTIR spectroscopy were used to characterize the conformational change during the aggregation process. Results suggest that designed breaker peptides may be useful to inhibit and disrupt not only Aβ peptide but related peptides that undergo aggregation.
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Wang J, Makris G, Kuchuk M, Radford L, Gallazzi F, Lewis MR, Jurisson SS, Hennkens HM. Direct labeling of a somatostatin receptor antagonist via peptide cyclization with Re, 99mTc and 186Re metal centers: Radiochemistry and in vitro evaluation. Nucl Med Biol 2021; 94-95:46-52. [PMID: 33515899 DOI: 10.1016/j.nucmedbio.2020.12.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/09/2020] [Accepted: 12/20/2020] [Indexed: 11/26/2022]
Abstract
INTRODUCTION With the long-term goal of developing a diagnostic (99mTc) and therapeutic (186Re) agent pair for targeting somatostatin receptor (SSTR)-positive neuroendocrine tumors (NETs), we developed novel metal-cyclized peptides through direct labeling of the potent SSTR2 antagonist Ac-4-NO2-Phe-c(DCys-Tyr-DTrp-Lys-Thr-Cys)-DTyr-NH2 (1) with Re (in Re-1), 99mTc (in [99mTc]Tc-1) and 186Re (in [186Re]Re-1). METHODS Re-1 was characterized by LC-ESI-MS and HR-ESI-MS and was tested for receptor affinity in SSTR-expressing cells (AR42J). Radiolabeling of the peptide was achieved via ligand exchange from 99mTc-labeled glucoheptonate or [186Re]ReOCl3(PPh3)2, yielding [99mTc]Tc-1 or [186Re]Re-1, respectively. In vitro stability of [99mTc]Tc-1/[186Re]Re-1 in PBS (10 mM) at pH 7.4 and 37 °C was determined by HPLC analysis. Moreover, [99mTc]Tc-1 stability was tested in cysteine (1 mM) and rat serum under the same conditions. RESULTS Re-1 consisted of two isomers, confirmed by LC-ESI-MS, with good SSTR2 affinity (IC50 = 43 ± 6 nM). Optimization of the 99mTc labeling through varying reaction parameters such as pH, reaction time, and Sn2+ and ligand concentrations resulted in high radiochemical yield (RCY ≥92%). Similarly, [186Re]Re-1 was prepared in reasonable RCY (≥50%). Both 99mTc/186Re-tracers consisted of two product isomers as identified by HPLC co-injection with Re-1. While [99mTc]Tc-1 was sufficiently stable in vitro (≥71% intact through 4 h in PBS, cysteine and rat serum), [186Re]Re-1 exhibited more moderate in vitro stability (58% intact after 1 h in PBS). CONCLUSIONS Novel 99mTc/186Re-cyclized SSTR2 antagonist peptides were synthesized and characterized using the Re-cyclized analogue as a reference. Due to the nanomolar SSTR2 affinity of Re-1 and good in vitro stability of [99mTc]Tc-1, the latter shows early promise for development as a radiodiagnostic agent for SSTR-expressing NETs. ADVANCES IN KNOWLEDGE AND IMPLICATIONS FOR PATIENT CARE The 99mTc-cyclized complex showed promising in vitro properties, and future in vivo studies will determine the potential for translating such a design into the human clinic.
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Affiliation(s)
- Jing Wang
- Research Reactor Center, University of Missouri, Columbia, MO 65211, USA; Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan 621900, PR China
| | - George Makris
- Research Reactor Center, University of Missouri, Columbia, MO 65211, USA
| | - Marina Kuchuk
- Research Reactor Center, University of Missouri, Columbia, MO 65211, USA
| | - Lauren Radford
- Department of Chemistry, University of Missouri, Columbia, MO 65211, USA
| | - Fabio Gallazzi
- Department of Chemistry, University of Missouri, Columbia, MO 65211, USA; Molecular Interactions Core, University of Missouri, Columbia, MO 65211, USA
| | - Michael R Lewis
- Department of Veterinary Medicine and Surgery, University of Missouri, Columbia, MO 65211, USA
| | - Silvia S Jurisson
- Department of Chemistry, University of Missouri, Columbia, MO 65211, USA
| | - Heather M Hennkens
- Research Reactor Center, University of Missouri, Columbia, MO 65211, USA; Department of Chemistry, University of Missouri, Columbia, MO 65211, USA.
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Abstract
Ortho-Phthalaldehyde (OPA)-amine reaction and OPA-amine-thiol reaction have been developed to effectively modify native peptides and proteins under the physiological conditions. First, OPA and its derivatives can rapidly and smoothly react with primary amine moieties in peptides and proteins to achieve native protein biconjugations. Furthermore, OPA-alkyne bifunctional linkers can be used for proteome profiling. Second, OPA-amine-thiol three-component reaction has been developed for chemoselective peptide cyclization, directly on unprotected peptides in the aqueous buffer. Moreover, this OPA-guided cyclic peptide can be further modified with the N-maleimide moiety in one pot to introduce additional functionalities. The development of this OPA based chemoselective bioconjugation and peptide cyclization extends the toolbox for protein chemical modification and construction of cyclic peptides.
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Abstract
Click chemistry is a powerful tool in constraining peptides into their active conformations. This chapter presents recent advancements involving the use of copper-catalyzed [3 + 2] azide-alkyne cycloaddition (CuAAC), better known as "click reaction" in the design and synthesis of cyclic peptide and cyclic peptidomimetic compounds. The usage of "click chemistry" reactions includes various topics: (a) mimicking peptide bonds; (b) synthesis of ordered structures; (c) ligation of peptidomimetic scaffolds; and most importantly in this chapter (d) cyclization of peptidomimetic scaffolds using the triazole ring as constraint of conformation.
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Liu H, Gao L, Yu X, Zhong L, Shi J, Jia B, Li N, Liu Z, Wang F. Small-animal SPECT/CT imaging of cancer xenografts and pulmonary fibrosis using a 99mTc-labeled integrin αvβ6-targeting cyclic peptide with improved in vivo stability. Biophys Rep 2018; 4:254-264. [PMID: 30533490 PMCID: PMC6245143 DOI: 10.1007/s41048-018-0071-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 07/17/2018] [Indexed: 12/20/2022] Open
Abstract
Abstract Integrin αvβ6 is expressed at an undetectable level in normal tissues, but is remarkably upregulated during many pathological processes, especially in cancer and fibrosis. Noninvasive imaging of integrin αvβ6 expression using a radiotracer with favorable in vivo pharmacokinetics would facilitate disease diagnosis and therapy monitoring. Through disulfide-cyclized method, we synthesized in this study, a new integrin αvβ6-targeted cyclic peptide (denoted as cHK), and radiolabeled it with 99mTc. The ability of the resulting radiotracer 99mTc–HYNIC–cHK to detect integrin αvβ6 expression in pancreatic cancer xenografts and idiopathic pulmonary fibrosis was evaluated using small-animal single-photon emission computed tomography (SPECT)/computed tomography (CT). 99mTc–HYNIC–cHK showed significantly improved in vivo metabolic stability compared to the linear peptide-based radiotracer 99mTc–HYNIC–HK. 99mTc–HYNIC–cHK exhibited similar biodistribution properties to 99mTc–HYNIC–HK, but the tumor-to-muscle ratio was significantly increased (2.99 ± 0.87 vs. 1.82 ± 0.27, P < 0.05). High-contrast images of integrin αvβ6-positive tumors and bleomycin-induced fibrotic lungs were obtained by SPECT/CT imaging using 99mTc–HYNIC–cHK. Overall, our studies demonstrate that 99mTc–HYNIC–cHK is a promising SPECT radiotracer for the noninvasive imaging of integrin αvβ6 in living subjects. Graphical Abstract ![]()
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Affiliation(s)
- Hao Liu
- Medical Isotopes Research Center and Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191 China
| | - Liquan Gao
- Medical Isotopes Research Center and Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191 China
| | - Xinhe Yu
- Medical Isotopes Research Center and Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191 China
| | - Lijun Zhong
- Medical and Healthy Analytical Center, Peking University, Beijing, 100191 China
| | - Jiyun Shi
- Key Laboratory of Protein and Peptide Pharmaceuticals, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
| | - Bing Jia
- Medical Isotopes Research Center and Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191 China
- Medical and Healthy Analytical Center, Peking University, Beijing, 100191 China
| | - Nan Li
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Nuclear Medicine, Peking University Cancer Hospital & Institute, Beijing, 100142 China
| | - Zhaofei Liu
- Medical Isotopes Research Center and Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191 China
| | - Fan Wang
- Medical Isotopes Research Center and Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191 China
- Key Laboratory of Protein and Peptide Pharmaceuticals, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
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Fang WJ, Murray TF, Aldrich JV. Design, synthesis, and opioid activity of arodyn analogs cyclized by ring-closing metathesis involving Tyr(allyl). Bioorg Med Chem 2017; 26:1157-1161. [PMID: 29273415 DOI: 10.1016/j.bmc.2017.11.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 11/14/2017] [Accepted: 11/17/2017] [Indexed: 01/31/2023]
Abstract
Kappa (κ) opioid receptor selective antagonists are useful pharmacological tools in studying κ opioid receptors and have potential to be used as therapeutic agents for the treatment of a variety of diseases including mood disorders and drug addiction. Arodyn (Ac[Phe1-3,Arg4,d-Ala8]Dyn A-(1-11)NH2) is a linear acetylated dynorphin A (Dyn A) analog that is a potent and selective κ opioid receptor antagonist (Bennett et al. J Med Chem 2002;45:5617-5619) and prevents stress-induced reinstatement of cocaine-seeking behavior following central administration (Carey et al. Eur J Pharmacol 2007;569:84-89). To restrict its conformational mobility, explore possible bioactive conformations and potentially increase its metabolic stability we synthesized cyclic arodyn analogs on solid phase utilizing a novel ring-closing metathesis (RCM) reaction involving allyl-protected Tyr (Tyr(All)) residues. This approach preserves the aromatic functionality and directly constrains the side chains of one or more of the Phe residues. The novel cyclic arodyn analog 4 cyclized between Tyr(All) residues incorporated in positions 2 and 3 exhibited potent κ opioid receptor antagonism in the [35S]GTPγS assay (KB = 3.2 nM) similar to arodyn. Analog 3 cyclized between Tyr(All) residues in positions 1 and 2 also exhibited nanomolar κ opioid receptor antagonist potency (KB = 27.5 nM) in this assay. These are the first opioid peptides cyclized via RCM involving aromatic residues, and given their promising pharmacological activity represent novel lead peptides for further exploration.
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Affiliation(s)
- Wei-Jie Fang
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66045, USA
| | - Thomas F Murray
- Department of Pharmacology, Creighton University, Omaha, NE 68178, USA
| | - Jane V Aldrich
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66045, USA; Department of Medicinal Chemistry, University of Florida, Gainesville, FL 32610, USA.
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