1
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Zhao X, Zhao X, Di W, Wang C. Inhibitors of Cyclophilin A: Current and Anticipated Pharmaceutical Agents for Inflammatory Diseases and Cancers. Molecules 2024; 29:1235. [PMID: 38542872 PMCID: PMC10974348 DOI: 10.3390/molecules29061235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/02/2024] [Accepted: 03/05/2024] [Indexed: 04/07/2024] Open
Abstract
Cyclophilin A, a widely prevalent cellular protein, exhibits peptidyl-prolyl cis-trans isomerase activity. This protein is predominantly located in the cytosol; additionally, it can be secreted by the cells in response to inflammatory stimuli. Cyclophilin A has been identified to be a key player in many of the biological events and is therefore involved in several diseases, including vascular and inflammatory diseases, immune disorders, aging, and cancers. It represents an attractive target for therapeutic intervention with small molecule inhibitors such as cyclosporin A. Recently, a number of novel inhibitors of cyclophilin A have emerged. However, it remains elusive whether and how many cyclophilin A inhibitors function in the inflammatory diseases and cancers. In this review, we discuss current available data about cyclophilin A inhibitors, including cyclosporin A and its derivatives, quinoxaline derivatives, and peptide analogues, and outline the most recent advances in clinical trials of these agents. Inhibitors of cyclophilin A are poised to enhance our comprehension of the molecular mechanisms that underpin inflammatory diseases and cancers associated with cyclophilin A. This advancement will aid in the development of innovative pharmaceutical treatments in the future.
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Affiliation(s)
- Xuemei Zhao
- School of Pharmaceutical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Ji’nan 250000, China; (X.Z.); (W.D.)
| | - Xin Zhao
- School of Pharmaceutical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Ji’nan 250000, China; (X.Z.); (W.D.)
| | - Weihua Di
- School of Pharmaceutical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Ji’nan 250000, China; (X.Z.); (W.D.)
| | - Chang Wang
- School of Pharmaceutical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Ji’nan 250000, China; (X.Z.); (W.D.)
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Ji’nan 250000, China
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2
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Fojnica A, Gromilic Z, Vranic S, Murkovic M. Anticancer Potential of the Cyclolinopeptides. Cancers (Basel) 2023; 15:3874. [PMID: 37568690 PMCID: PMC10416992 DOI: 10.3390/cancers15153874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 07/25/2023] [Accepted: 07/28/2023] [Indexed: 08/13/2023] Open
Abstract
Novel therapeutic agents to combat cancer is an active area of research, as current treatment options have limitations in efficacy and tolerability. One of these therapeutic agents in our immediate environment is cyclolinopeptides (CLPs). CLPs have several advantages that make them suitable for daily consumption and potential therapeutics in cancer research. They are natural compounds, having high specificity, low toxicity, low cost, and an overall simple extraction process. Over the years, numerous in vitro studies in cancer cells demonstrated CLPs to possess anti-proliferative, apoptotic, and anti-angiogenic effects, as well as the ability to induce cell cycle arrest and inhibit cancer cell growth in various cancer types, including breast cancer, gastric cancer, and melanoma. This paper provides an overview of the significance and potential of CLPs as therapeutic agents, emphasizing their promising role in cancer treatment based on different cancer cell lines. The mechanism of action of CLPs in cancer cells is multifaceted. It involves the modulation of multiple signaling pathways, including inhibition of protein kinases, modulation of apoptosis-related proteins, and regulation of oxidative stress and inflammation.
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Affiliation(s)
- Adnan Fojnica
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, 8036 Graz, Austria;
- Institute of Biochemistry, Graz University of Technology, 8010 Graz, Austria;
| | - Zehra Gromilic
- Institute of Biochemistry, Graz University of Technology, 8010 Graz, Austria;
| | - Semir Vranic
- College of Medicine, QU Health, Qatar University, Doha 2713, Qatar;
| | - Michael Murkovic
- Institute of Biochemistry, Graz University of Technology, 8010 Graz, Austria;
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3
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Mueed A, Madjirebaye P, Shibli S, Deng Z. Flaxseed Peptides and Cyclolinopeptides: A Critical Review on Proteomic Approaches, Biological Activity, and Future Perspectives. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:14600-14612. [PMID: 36355404 DOI: 10.1021/acs.jafc.2c06769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Linusorbs (LOs) and peptides from flaxseed protein have documented biological activity, such as angiotensin-converting enzyme inhibition, antioxidant, anticancer, and immunosuppressive activities, but their mechanism and structure-related bioactivity have not been summarized previously. Therefore, this study reviews the structure, composition, bioavailability, and health benefits of flaxseed peptides and LOs as well as peptide generation and LO modification. However, these peptides and LOs are long linear and cyclic structures, which affect the absorption and bioavailability of these substances in living beings and, thus, impair their overall efficiency and pharmacological effectiveness. Therefore, the development of novel strategies for optimizing the bioavailability of these peptide compounds is critical to ensure their successful application and delivery to the target sites via specially designed methods that will significantly improve their in vivo concentration and also investigate the structure-related activity of distinct amino acid and functional groups in physiological activity. Additionally, these native peptides and their analogues can be used as scaffolds for the production of antibodies.
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Affiliation(s)
- Abdul Mueed
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, People's Republic of China
| | - Philippe Madjirebaye
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, People's Republic of China
| | - Sahar Shibli
- Food Science Research Institute, National Agricultural Research Center, Islamabad 44000, Pakistan
| | - Zeyuan Deng
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, People's Republic of China
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4
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Uptake of Flaxseed Dietary Linusorbs Modulates Regulatory Genes Including Induction of Heat Shock Proteins and Apoptosis. Foods 2022; 11:foods11233761. [PMID: 36496568 PMCID: PMC9741104 DOI: 10.3390/foods11233761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/17/2022] [Accepted: 11/18/2022] [Indexed: 11/24/2022] Open
Abstract
Flaxseed (Linum usitatissimum L.) is gaining popularity as a superfood due to its health-promoting properties. Mature flax grain includes an array of biologically active cyclic peptides or linusorbs (LOs, also known as cyclolinopeptides) that are synthesized from three or more ribosome-derived precursors. Two flaxseed orbitides, [1-9-NαC]-linusorb B3 and [1-9-NαC]-linusorb B2, suppress immunity, induce apoptosis in a cell line derived from human epithelial cancer cells (Calu-3), and inhibit T-cell proliferation, but the mechanism of LO action is unknown. LO-induced changes in gene expression in both nematode cultures and human cancer cell lines indicate that LOs promoted apoptosis. Specific evidence of LO bioactivity included: (1) distribution of LOs throughout the organism after flaxseed consumption; (2) induction of heat shock protein (HSP) 70A, an indicator of stress; (3) induction of apoptosis in Calu-3 cells; and (4) modulation of regulatory genes (determined by microarray analysis). In specific cancer cells, LOs induced apoptosis as well as HSPs in nematodes. The uptake of LOs from dietary sources indicates that these compounds might be suitable as delivery platforms for a variety of biologically active molecules for cancer therapy.
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5
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Shim YY, Kim JH, Cho JY, Reaney MJT. Health benefits of flaxseed and its peptides (linusorbs). Crit Rev Food Sci Nutr 2022; 64:1845-1864. [PMID: 36193986 DOI: 10.1080/10408398.2022.2119363] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Flaxseed (Linum usitatissimum L.) has been associated with numerous health benefits. The flax plant synthesizes an array of biologically active compounds including peptides or linusorbs (LOs, a.k.a., cyclolinopeptides), lignans, soluble dietary fiber and omega-3 fatty acids. The LOs arise from post-translational modification of four or more ribosome-derived precursors. These compounds exhibit an array of biological activities, including suppression of T-cell proliferation, excessive inflammation, and osteoclast replication as well as induction of apoptosis in some cancer cell lines. The mechanisms of LO action are only now being elucidated but these compounds might interact with other active compounds in flaxseed and contribute to biological activity attributed to other flax compounds. This review focuses on both the biological interaction of LOs with proteins and other molecules and comprehensive knowledge of LO pharmacological and biological properties. The physicochemical and nutraceutical properties of LOs, as well as the biological effects of certain LOs, and their underlying mechanisms of action, are reviewed. Finally, strategies for producing LOs by either peptide synthesis or recombinant organisms are presented. This review will be the first to describe LOs as a versatile scaffold for the action of compounds to deliver physiochemically/biologically active molecules for developing novel nutraceuticals and pharmaceuticals.
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Affiliation(s)
- Youn Young Shim
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Department of Integrative Biotechnology, Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Suwon, Gyeonggi-do, Korea
- Prairie Tide Diversified Inc, Saskatoon, Saskatchewan, Canada
- Guangdong Saskatchewan Oilseed Joint Laboratory, Department of Food Science and Engineering, Jinan University, Guangzhou, Guangdong, China
| | - Ji Hye Kim
- Department of Integrative Biotechnology, Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Suwon, Gyeonggi-do, Korea
| | - Jae Youl Cho
- Department of Integrative Biotechnology, Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Suwon, Gyeonggi-do, Korea
| | - Martin J T Reaney
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Prairie Tide Diversified Inc, Saskatoon, Saskatchewan, Canada
- Guangdong Saskatchewan Oilseed Joint Laboratory, Department of Food Science and Engineering, Jinan University, Guangzhou, Guangdong, China
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6
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Gruber KA, Ji RL, Gallazzi F, Jiang S, Van Doren SR, Tao YX, Newton Northup J. Development of a Therapeutic Peptide for Cachexia Suggests a Platform Approach for Drug-like Peptides. ACS Pharmacol Transl Sci 2022; 5:344-361. [PMID: 35592439 PMCID: PMC9112415 DOI: 10.1021/acsptsci.1c00270] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Indexed: 12/19/2022]
Abstract
During the development of a melanocortin (MC) peptide drug to treat the condition of cachexia (a hypermetabolic state producing lean body mass wasting), we were confronted with the need for peptide transport across the blood-brain barrier (BBB): the MC-4 receptors (MC4Rs) for metabolic rate control are located in the hypothalamus, i.e., behind the BBB. Using the term "peptides with BBB transport", we screened the medical literature like a peptide library. This revealed numerous "hits"-peptides with BBB transport and/or oral activity. We noted several features common to most peptides in this class, including a dipeptide sequence of nonpolar residues, primary structure cyclization (whole or partial), and a Pro-aromatic motif usually within the cyclized region. Based on this, we designed an MC4R antagonist peptide, TCMCB07, that successfully treated many forms of cachexia. As part of our pharmacokinetic characterization of TCMCB07, we discovered that hepatobiliary extraction from blood accounted for a majority of the circulating peptide's excretion. Further screening of the literature revealed that TCMCB07 is a member of a long-forgotten peptide class, showing active transport by a multi-specific bile salt carrier. Bile salt transport peptides have predictable pharmacokinetics, including BBB transport, but rapid hepatic clearance inhibited their development as drugs. TCMCB07 shares the general characteristics of the bile salt peptide class but with a much longer half-life of hours, not minutes. A change in its C-terminal amino acid sequence slows hepatic clearance. This modification is transferable to other peptides in this class, suggesting a platform approach for producing drug-like peptides.
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Affiliation(s)
- Kenneth A Gruber
- John M. Dalton Cardiovascular Research Center, and Department of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri 65211, United States.,Tensive Controls, Inc., Columbia, Missouri 65211, United States
| | - Ren-Lai Ji
- Department of Anatomy, Physiology and Pharmacology, Auburn University, College of Veterinary Medicine, Auburn, Alabama 36849, United States
| | - Fabio Gallazzi
- Department of Chemistry and Molecular Interaction Core, University of Missouri, Columbia, Missouri 65211, United States
| | - Shaokai Jiang
- Department of Chemistry and NMR Core, University of Missouri, Columbia, Missouri 65211, United States
| | - Steven R Van Doren
- Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, United States`
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, Auburn University, College of Veterinary Medicine, Auburn, Alabama 36849, United States
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7
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Lang T, Frank O, Lang R, Hofmann T, Behrens M. Activation Spectra of Human Bitter Taste Receptors Stimulated with Cyclolinopeptides Corresponding to Fresh and Aged Linseed Oil. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:4382-4390. [PMID: 35364812 PMCID: PMC9011397 DOI: 10.1021/acs.jafc.2c00976] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/16/2022] [Accepted: 03/21/2022] [Indexed: 06/14/2023]
Abstract
Linseed oil is rich in unsaturated fatty acids, and its increased consumption could aid in health-promoting nutrition. However, rapid oxidation of linseed oil and concomitant development of bitterness impair consumers' acceptance. Previous research revealed that cyclolinopeptides, a group of cyclic peptides inherent to linseed oil, dominantly contribute to the observed bitterness. In the present study, fresh and stored linseed oil and flaxseed were analyzed for the presence of cyclolinopeptides using preparative high-performance liquid chromatography combined with mass spectrometry- and nuclear magnetic resonance-based identification and quantification. The purified compounds were tested for the activation of all 25 human bitter taste receptors of which only two responded exclusively to methionine-oxidized cyclolinopeptides. Of those, the methionine sulfoxide-containing cyclolinopeptide-4 elicited responses at relevant concentrations. We conclude that this compound is the main determinant of linseed oil's bitterness and propose strategies to reduce the development of bitterness.
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Affiliation(s)
- Tatjana Lang
- Leibniz
Institute for Food Systems Biology, Technical
University of Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany
- Chair
of Food Chemistry and Molecular Sensory Science, Technical University of Munich, 85354 Freising, Germany
| | - Oliver Frank
- Chair
of Food Chemistry and Molecular Sensory Science, Technical University of Munich, 85354 Freising, Germany
| | - Roman Lang
- Leibniz
Institute for Food Systems Biology, Technical
University of Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany
- Chair
of Food Chemistry and Molecular Sensory Science, Technical University of Munich, 85354 Freising, Germany
| | - Thomas Hofmann
- Chair
of Food Chemistry and Molecular Sensory Science, Technical University of Munich, 85354 Freising, Germany
| | - Maik Behrens
- Leibniz
Institute for Food Systems Biology, Technical
University of Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany
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8
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Damjanovic J, Miao J, Huang H, Lin YS. Elucidating Solution Structures of Cyclic Peptides Using Molecular Dynamics Simulations. Chem Rev 2021; 121:2292-2324. [PMID: 33426882 DOI: 10.1021/acs.chemrev.0c01087] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Protein-protein interactions are vital to biological processes, but the shape and size of their interfaces make them hard to target using small molecules. Cyclic peptides have shown promise as protein-protein interaction modulators, as they can bind protein surfaces with high affinity and specificity. Dozens of cyclic peptides are already FDA approved, and many more are in various stages of development as immunosuppressants, antibiotics, antivirals, or anticancer drugs. However, most cyclic peptide drugs so far have been natural products or derivatives thereof, with de novo design having proven challenging. A key obstacle is structural characterization: cyclic peptides frequently adopt multiple conformations in solution, which are difficult to resolve using techniques like NMR spectroscopy. The lack of solution structural information prevents a thorough understanding of cyclic peptides' sequence-structure-function relationship. Here we review recent development and application of molecular dynamics simulations with enhanced sampling to studying the solution structures of cyclic peptides. We describe novel computational methods capable of sampling cyclic peptides' conformational space and provide examples of computational studies that relate peptides' sequence and structure to biological activity. We demonstrate that molecular dynamics simulations have grown from an explanatory technique to a full-fledged tool for systematic studies at the forefront of cyclic peptide therapeutic design.
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Affiliation(s)
- Jovan Damjanovic
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Jiayuan Miao
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - He Huang
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Yu-Shan Lin
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
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9
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Purdy SK, Spasyuk D, Chitanda JM, Reaney MJT. [1–9-NαC]-Linusorb B3 (Cyclolinopeptide A) dimethyl sulfoxide monosolvate. IUCRDATA 2020; 5:x200318. [PMID: 36339484 PMCID: PMC9462193 DOI: 10.1107/s2414314620003181] [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: 02/15/2020] [Accepted: 03/06/2020] [Indexed: 11/30/2022] Open
Abstract
[1–9-NαC]-Linusorb B3 (Cyclolinopeptide A) was extracted from flaxseed oil crystals formed in dimethyl sulfoxide. The molecule has four intramolecular N—H⋯O hydrogen bonds, and the DMSO solvate molecule is bound to the Phe6 amino acid by a fifth N—H⋯O hydrogen bond. Crystals of the dimethyl sulfoxide (DMSO) solvate of [1–9-NαC]-linusorb B3 (Cyclolinopeptide A; CLP-A; C57H84N9O9·C2H6OS), a cyclic polypeptide were obtained following peptide extraction and purification from flaxseed oil. There are four intramolecular N—H⋯O hydrogen bonds. In the crystal, the molecules are linked in chains along the a axis by N—H⋯O hydrogen bonds. Each DMSO O atom accepts a hydrogen bond from an NH group at the Phe6 location in the CLP-A molecule.![]()
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10
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Shim YY, Song Z, Jadhav PD, Reaney MJ. Orbitides from flaxseed (Linum usitatissimum L.): A comprehensive review. Trends Food Sci Technol 2019. [DOI: 10.1016/j.tifs.2019.09.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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11
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Slough DP, McHugh SM, Lin YS. Understanding and designing head-to-tail cyclic peptides. Biopolymers 2018; 109:e23113. [PMID: 29528114 PMCID: PMC6135719 DOI: 10.1002/bip.23113] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 02/23/2018] [Accepted: 02/26/2018] [Indexed: 01/30/2023]
Abstract
Cyclic peptides (CPs) are an exciting class of molecules with a variety of applications. However, design strategies for CP therapeutics, for example, are generally limited by a poor understanding of their sequence-structure relationships. This knowledge gap often leads to a trial-and-error approach for designing CPs for a specific purpose, which is both costly and time-consuming. Herein, we describe the current experimental and computational efforts in understanding and designing head-to-tail CPs along with their respective challenges. In addition, we provide several future directions in the field of computational CP design to improve its accuracy, efficiency and applicability. These advances, combined with experimental techniques, shall ultimately provide a better understanding of these interesting molecules and a reliable working platform to rationally design CPs with desired characteristics.
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Affiliation(s)
| | | | - Yu-Shan Lin
- Department of Chemistry, Tufts University, Medford, Massachusetts, 02155, United States
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12
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Burnett PGG, Young LW, Olivia CM, Jadhav PD, Okinyo-Owiti DP, Reaney MJT. Novel flax orbitide derived from genetic deletion. BMC PLANT BIOLOGY 2018; 18:90. [PMID: 29783946 PMCID: PMC5963108 DOI: 10.1186/s12870-018-1303-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 04/30/2018] [Indexed: 05/10/2023]
Abstract
BACKGROUND Flaxseed orbitides are homodetic plant cyclic peptides arising from ribosomal synthesis and post-translation modification (N to C cyclization), and lacking cysteine double bonds (Nat Prod Rep 30:108-160, 2013). Screening for orbitide composition was conducted on the flax core collection (FCC) grown at both Saskatoon, Saskatchewan and Morden, Manitoba over three growing seasons (2009-2011). Two flax (Linum usitatissimum L.) accessions 'Hollandia' (CN 98056) and 'Z 11637' (CN 98150) produce neither [1-9-NαC]-linusorb B2 (3) nor [1-9-NαC]-linusorb B3 (1). Mass spectrometry was used to identify novel compounds and elucidate their structure. NMR spectroscopy was used to corroborate structural information. RESULTS Experimental findings indicated that these accessions produce a novel orbitide, identified in three oxidation states having quasimolecular ion peaks at m/z 1072.6 (18), 1088.6 (19), and 1104.6 (20) [M + H]+ corresponding to molecular formulae C57H86N9O9S, C57H86N9O10S, and C57H86N9O11S, respectively. The structure of 19 was confirmed unequivocally as [1-9-NαC]-OLIPPFFLI. PCR amplification and sequencing of the gene coding for 18, using primers developed for 3 and 1, identified the putative linear precursor protein of 18 as being comprised of the first three amino acid residues of 3 (MLI), four conserved amino acid residues of 3 and/or 1 (PPFF), and the last two residues of 1 (LI). CONCLUSION Comparison of gene sequencing data revealed that a 117 base pair deletion had occurred that resulted in truncation of both 3 and 1 to produce a sequence encoding for the novel orbitide precursor of 18. This observation suggests that repeat units of flax orbitide genes are conserved and suggests a novel mechanism for evolution of orbitide gene diversity. Orbitides 19 and 20 contain MetO and MetO2, respectively, and are not directly encoded, but are products of post-translation modification of Met present in 18 ([1-9-NαC]-MLIPPFFLI).
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Affiliation(s)
- Peta-Gaye Gillian Burnett
- Department of Plant Sciences, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK S7N 5A8 Canada
| | - Lester Warren Young
- Department of Plant Sciences, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK S7N 5A8 Canada
| | - Clara Marisa Olivia
- Department of Food and Bioproduct Sciences, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK S7N 5A8 Canada
| | - Pramodkumar Dinkar Jadhav
- Department of Plant Sciences, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK S7N 5A8 Canada
| | - Denis Paskal Okinyo-Owiti
- Department of Plant Sciences, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK S7N 5A8 Canada
| | - Martin John Tarsisius Reaney
- Department of Plant Sciences, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK S7N 5A8 Canada
- Guangdong Saskatchewan Oilseed Joint Laboratory, Department of Food Science and Engineering, Jinan University, Guangzhou, 510632 Guangdong China
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13
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McHugh SM, Yu H, Slough DP, Lin YS. Mapping the sequence-structure relationships of simple cyclic hexapeptides. Phys Chem Chem Phys 2018; 19:3315-3324. [PMID: 28091629 DOI: 10.1039/c6cp06192c] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cyclic peptides are promising protein-protein interaction modulators with high binding affinities and specificities, as well as enhanced stabilities and oral availabilities over linear analogs. Despite their relatively small size and cyclic architecture, it is currently difficult to predict the favored conformation(s) of most classes of cyclic peptides. An improved understanding of the sequence-structure relationships for cyclic peptides will offer an avenue for the rational design of cyclic peptides as possible therapeutics. In this work, we systematically explored the sequence-structure relationships for two cyclic hexapeptide systems using molecular dynamics simulation techniques. Starting with an all-glycine cyclic hexapeptide, cyclo-G6, we systematically replaced glycine residues with alanines and characterized the structural ensembles of different variants. The same process was repeated with valines to investigate the effects of larger side chains. An analysis of the origin of structure preferences was performed using thermodynamics decomposition and several general observations are reported.
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Affiliation(s)
- Sean M McHugh
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA.
| | - Hongtao Yu
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA.
| | - Diana P Slough
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA.
| | - Yu-Shan Lin
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA.
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14
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Parikh M, Netticadan T, Pierce GN. Flaxseed: its bioactive components and their cardiovascular benefits. Am J Physiol Heart Circ Physiol 2018; 314:H146-H159. [DOI: 10.1152/ajpheart.00400.2017] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Cardiovascular disease remains the leading cause of mortality and morbidity worldwide. The inclusion of functional foods and natural health products in the diet are gaining increasing recognition as integral components of lifestyle changes in the fight against cardiovascular disease. Several preclinical and clinical studies have shown the beneficial cardiovascular effects of dietary supplementation with flaxseed. The cardiovascular effects of dietary flaxseed have included an antihypertensive action, antiatherogenic effects, a lowering of cholesterol, an anti-inflammatory action, and an inhibition of arrhythmias. Its enrichment in the ω-3 fatty acid α-linolenic acid and the antioxidant lignan secoisolariciresinol diglucoside as well as its high fiber content have been implicated primarily in these beneficial cardiovascular actions. Although not as well recognized, flaxseed is also composed of other potential bioactive compounds such as proteins, cyclolinopeptides, and cyanogenic glycosides, which may also produce biological actions. These compounds could also be responsible for the cardiovascular effects of flaxseed. This article will not only summarize the cardiovascular effects of dietary supplementation with flaxseed but also review its bioactive compounds in terms of their properties, biological effects, and proposed mechanisms of action. It will also discuss promising research directions for the future to identify additional health-related benefits of dietary flaxseed.
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Affiliation(s)
- Mihir Parikh
- Department of Physiology and Pathophysiology, Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
- Canadian Centre for Agri-food Research in Health and Medicine, Winnipeg, Manitoba, Canada
- Institute of Cardiovascular Sciences, St. Boniface Hospital, Albrechtsen Research Centre, Winnipeg, Manitoba, Canada
| | - Thomas Netticadan
- Agriculture and Agri-food Canada, Winnipeg, Manitoba, Canada
- Canadian Centre for Agri-food Research in Health and Medicine, Winnipeg, Manitoba, Canada
| | - Grant N. Pierce
- Department of Physiology and Pathophysiology, Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
- Canadian Centre for Agri-food Research in Health and Medicine, Winnipeg, Manitoba, Canada
- Institute of Cardiovascular Sciences, St. Boniface Hospital, Albrechtsen Research Centre, Winnipeg, Manitoba, Canada
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15
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McHugh SM, Rogers JR, Yu H, Lin YS. Insights into How Cyclic Peptides Switch Conformations. J Chem Theory Comput 2016; 12:2480-8. [DOI: 10.1021/acs.jctc.6b00193] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sean M. McHugh
- Department
of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Julia R. Rogers
- Department
of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Hongtao Yu
- Department
of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Yu-Shan Lin
- Department
of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
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16
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Jadhav PD, Shen J, Sammynaiken R, Reaney MJT. Site Covalent Modification of Methionyl Peptides for the Production of FRET Complexes. Chemistry 2015; 21:17023-34. [DOI: 10.1002/chem.201502699] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Indexed: 11/05/2022]
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17
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Shim YY, Reaney MJT. Kinetic Interactions between Cyclolinopeptides and Immobilized Human Serum Albumin by Surface Plasmon Resonance. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:1099-1106. [PMID: 25554104 DOI: 10.1021/jf504811x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Cyclolinopeptides (CLs) are octa-, nona-, and decapeptides present in flaxseed (Linum usitatissimum L.) that may have immunosuppressive and antitumor activities, but little is known of their pharmacokinetics. Human serum albumin (HSA), the most abundant blood protein, is an important mediator of organic solute flux, and hence when compounds bind this protein, it potentially affects both their availability and efficacy. Quantitative thermodynamic analysis of the interaction of compounds with HSA is important in the development of biomedical applications. A surface plasmon resonance (SPR) biosensor was utilized to reliably determine binding constants for several CLs with HSA. The maximum binding response of [1-9-NαC]-CLA/HSA was almost 20-fold higher than that of [1-8-NαC],[1-MetO]-CLE/HSA. Through analysis of an array of peptides, it was possible to correlate the impact of structural changes on CL binding. The oxidation of sulfur in methionine (Met) residues formed methionine S-oxide (MetO) and reduced binding significantly. Most strikingly, the further oxidation of MetO to S,S-dioxide (MetO2) produced CLs with stronger binding. The large impact on binding by relatively small modifications of methionine containing CLs suggested that small changes in methionine oxidation can disrupt hydrophobic interaction, the predominant intermolecular force stabilizing the complex between CLs and HSA. SPR binding studies may aid in understanding the fate of CLs after consumption of flaxseed or flaxseed products or the development of CLs as drugs or drug carriers.
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Affiliation(s)
- Youn Young Shim
- Department of Plant Sciences, University of Saskatchewan , Saskatoon, Saskatchewan S7N 5A8, Canada
- Prairie Tide Chemicals Inc., 102 Melville Street, Saskatoon, Saskatchewan S7J 0R1, Canada
| | - Martin J T Reaney
- Department of Plant Sciences, University of Saskatchewan , Saskatoon, Saskatchewan S7N 5A8, Canada
- Prairie Tide Chemicals Inc., 102 Melville Street, Saskatoon, Saskatchewan S7J 0R1, Canada
- Guangdong Saskatchewan Oilseed Joint Laboratory, Department of Food Science and Engineering, Jinan University , 601 Huangpu Avenue West, Guangdong, Guangzhou 510632, China
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18
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Jędrzejczak K, Hrynczyszyn P, Artym J, Kocięba M, Zimecki M, Zabrocki J, Jankowski S. Synthesis and biological activity of cyclolinopeptide A analogues modified with γ(3)-bis(homophenylalanine). Eur J Med Chem 2014; 86:515-27. [PMID: 25203781 DOI: 10.1016/j.ejmech.2014.09.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Revised: 09/01/2014] [Accepted: 09/04/2014] [Indexed: 01/01/2023]
Abstract
Cyclolinopeptide A, naturally occurring immunomodulatory nonapeptide, was modified with S or R-γ(3)-bis(homophenylalanine) in positions 3 or 4, or both 3 and 4. The replacement of one or both Phe residues by γ(3)-hhPhe led to decrease of their conformational flexibility in the analogues in comparison to CLA. All cyclic peptides, except 11, exist as isomers with the cis Pro-Pro peptide bond. Cyclic peptide 11 with single modification S-γ(3)-hhPhe(4) exists as a mixture of two isomers and the major isomer (89%) contains all peptide bonds of the trans geometry. The peptides were subjected to several immunological tests in vitro and in vivo. Linear peptides 1-8, precursors of CLA analogues 9-16, were not toxic against human peripheral blood mononuclear cells (PBMC) but cyclic analogues showed dose-dependent toxicity with exception of peptide 11. Linear peptides did not inhibit mitogen-induced PBMC proliferation whereas cyclic ones inhibited the proliferation in a dose-dependent manner. The actions of linear and cyclic peptides with regard to lipopolysaccharide (LPS) -induced tumour necrosis factor alpha (TNF α) production in whole human blood cultures were differential but particularly suppressive in the case of linear compound 6. Therefore, for in vivo tests compounds 6 and 11 were selected. The compounds showed comparable, suppressive actions in induction and effector phases of delayed type hypersensitivity as well as in the carrageenan-induced foot pad edema in mouse models. In summary, linear peptide 6 and cyclic peptide 11 are attractive as potential immune suppressor drugs.
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Affiliation(s)
- Karol Jędrzejczak
- Institute of Organic Chemistry, Faculty of Chemistry, Technical University of Łódź, Żeromskiego 116, 90-924, Poland
| | - Paweł Hrynczyszyn
- Institute of Organic Chemistry, Faculty of Chemistry, Technical University of Łódź, Żeromskiego 116, 90-924, Poland
| | - Jolanta Artym
- Institute of Immunology and Experimental Therapy, Polish Academy of Science, R. Weigla 12, 53-114 Wroclaw, Poland
| | - Maja Kocięba
- Institute of Immunology and Experimental Therapy, Polish Academy of Science, R. Weigla 12, 53-114 Wroclaw, Poland
| | - Michał Zimecki
- Institute of Immunology and Experimental Therapy, Polish Academy of Science, R. Weigla 12, 53-114 Wroclaw, Poland
| | - Janusz Zabrocki
- Institute of Organic Chemistry, Faculty of Chemistry, Technical University of Łódź, Żeromskiego 116, 90-924, Poland; Peptaderm Ltd., Rydygiera 8, 01-793 Warsaw, Poland
| | - Stefan Jankowski
- Institute of Organic Chemistry, Faculty of Chemistry, Technical University of Łódź, Żeromskiego 116, 90-924, Poland.
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19
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Huben K, Jewgiński M, Pabis A, Paluch P, Luy B, Jankowski S. The structure of cyclolinopeptide A in chloroform refined by RDC measurements. J Pept Sci 2014; 20:901-7. [DOI: 10.1002/psc.2683] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 07/16/2014] [Accepted: 07/17/2014] [Indexed: 11/07/2022]
Affiliation(s)
- Krzysztof Huben
- Institute of Organic Chemistry, Faculty of Chemistry; Lodz University of Technology; Żeromskiego 116 90-924 Lodz Poland
| | - Michał Jewgiński
- Department of Bioorganic Chemistry, Faculty of Chemistry; Wrocław University of Technology; Wybrzeże Wyspiańskiego 27 50-370 Wroclaw Poland
| | - Anna Pabis
- Institute of Applied Radiation Chemistry, Faculty of Chemistry; Lodz University of Technology; Żeromskiego 116 90-924 Lodz Poland
| | - Piotr Paluch
- Institute of Organic Chemistry, Faculty of Chemistry; Lodz University of Technology; Żeromskiego 116 90-924 Lodz Poland
- Centre of Molecular and Macromolecular Studies; PAS; Sienkiewicza 112 90-363 Lodz Poland
| | - Burkhard Luy
- Institute of Organic Chemistry and Institute for Biological Interfaces; Karlsruhe Institute of Technology (KIT); Fritz-Haber-Weg 6 76131 Karlsruhe Germany
| | - Stefan Jankowski
- Institute of Organic Chemistry, Faculty of Chemistry; Lodz University of Technology; Żeromskiego 116 90-924 Lodz Poland
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20
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Shim YY, Gui B, Arnison PG, Wang Y, Reaney MJ. Flaxseed (Linum usitatissimum L.) bioactive compounds and peptide nomenclature: A review. Trends Food Sci Technol 2014. [DOI: 10.1016/j.tifs.2014.03.011] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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21
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Gui B, Shim YY, Datla RSS, Covello PS, Stone SL, Reaney MJT. Identification and quantification of cyclolinopeptides in five flaxseed cultivars. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:8571-9. [PMID: 22897677 DOI: 10.1021/jf301847u] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Cyclolinopeptides are a group of naturally occurring hydrophobic cyclic peptides found in flaxseed and flax oil that have immunosuppressive activity. This study describes the measurement of flaxseed cyclolinopeptide concentrations using an internal standard HPLC method. In addition, the concentration of cyclolinopeptides in the seed of Canadian flax cultivars grown at two locations over two years is reported. The data are consistent with the formation of flaxseed cyclolinopeptides from two ribosome-derived precursors. Each precursor protein includes the sequences corresponding to three cyclolinopeptides from which those cyclolinopeptides are presumably derived by precursor processing. The concentrations of cyclolinopeptides C and E, which are encoded by the same gene sequence, are highly correlated, and the concentrations of cyclolinopeptides D, F, and G, which are encoded by a second gene sequence, are also highly correlated. The strong correlation between the cyclolinopeptides arising from the same gene may prove to be important in understanding how peptide concentration is controlled. Additional research may lead to approaches to improve flax either as a platform for peptide production or as a source of oil with improved drying properties and flavor.
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Affiliation(s)
- Bo Gui
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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22
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Olivia CM, Burnett PGG, Okinyo-Owiti DP, Shen J, Reaney MJ. Rapid reversed-phase liquid chromatography separation of cyclolinopeptides with monolithic and microparticulate columns. J Chromatogr B Analyt Technol Biomed Life Sci 2012; 904:128-34. [DOI: 10.1016/j.jchromb.2012.07.037] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 07/27/2012] [Accepted: 07/31/2012] [Indexed: 01/05/2023]
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23
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Ovadia O, Greenberg S, Laufer B, Gilon C, Hoffman A, Kessler H. Improvement of drug-like properties of peptides: the somatostatin paradigm. Expert Opin Drug Discov 2010; 5:655-71. [DOI: 10.1517/17460441.2010.493935] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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24
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Quail JW, Shen J, Reaney MJT, Sammynaiken R. Cyclo-linopeptide A methanol solvate. Acta Crystallogr Sect E Struct Rep Online 2009; 65:o1913-4. [PMID: 21583600 PMCID: PMC2977324 DOI: 10.1107/s1600536809026841] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Accepted: 07/08/2009] [Indexed: 11/23/2022]
Abstract
Crystals of the title compound, C57H85N9O9·CH4O, the methanol solvate of a nine peptide polypeptide, cyclo-(Pro-Pro-Phe-Phe-Leu-Ile-Ile-Leu-Val), were obtained after separation of the cyclic peptide from flax oil. The cyclolinopeptide A (CLP-A) molecules are linked in chains along the a axis by N—H⋯O hydrogen bonds. Each methanol O atom is hydrogen bonded to one O atom and two N—H groups in the same CLP-A molecule. There are a total of eight hydrogen bonds in each CLP-A–MeOH unit.
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25
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MORELLI MCASTIGLIONE, PASTORE A, PEDONE C, TEMUSSI P, ZANOTTI G, TANCREDI T. Conformational study of cyclolinopeptide A. ACTA ACUST UNITED AC 2009. [DOI: 10.1111/j.1399-3011.1991.tb00087.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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26
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Joshi KB, Verma S. Sequence shuffle controls morphological consequences in a self-assembling tetrapeptide. J Pept Sci 2008; 14:118-26. [DOI: 10.1002/psc.955] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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27
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Huang H, Mu LJ, Cheng JP, Lu JM, Hu XB. Synthesis Of A New Series Of Cyclic Pseudopeptides Containing Pyridine As Backbone Modifier. SYNTHETIC COMMUN 2006. [DOI: 10.1080/00397919808004529] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Hai Huang
- a Department of Chemistry , Nankai University , Tianjin , 300071 , China
| | - Lin-Jing Mu
- a Department of Chemistry , Nankai University , Tianjin , 300071 , China
| | - Jin-Pei Cheng
- a Department of Chemistry , Nankai University , Tianjin , 300071 , China
| | - Jian-Ming Lu
- a Department of Chemistry , Nankai University , Tianjin , 300071 , China
| | - Xu-Bo Hu
- a Department of Chemistry , Nankai University , Tianjin , 300071 , China
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28
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29
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Abstract
Cyclolinopeptide A (CLA), a cyclic nonapeptide from linseed, possesses strong immunosuppressive and antimalarial activity along with the ability to inhibit cholate uptake into hepatocytes. The structure of the peptide was studied extensively in solution as well as in the solid state. It is postulated that both the Pro-Pro cis-amide bond and an 'edge-to-face' interaction between the aromatic rings of two adjacent Phe residues are important for biological activity. Structure-activity relationship studies of many linear and cyclic analogues of CLA suggest that the Pro-Xxx-Phe sequence and the flexibility of the peptide are important for the immunosuppressive activity.
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Affiliation(s)
- Bolesław Picur
- Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie, 50-383 Wroclaw, Poland
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30
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Rossi F, Saviano M, Di Talia P, Di Blasio B, Pedone C, Zanotti G, Mosca M, Saviano G, Tancredi T, Ziegler K, Benedetti E. Solution and solid state structure of an aib-containing cyclodecapeptide inhibiting the cholate uptake in hepatocytes. Biopolymers 2000; 40:465-78. [PMID: 9062069 DOI: 10.1002/(sici)1097-0282(1996)40:5<465::aid-bip4>3.0.co;2-u] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The conformational analysis of synthetic cyclodecapeptide c(Pro-Phe-phe-Aib-Leu)2 related to the cyclolinopeptide A, in the solid state and solution, has been carried out by x-ray diffraction and nmr spectroscopy. The structure of the monoclinic form obtained from methanol [a = 11.351 (5) A, b = 27.455 (2) A, c = 12.716 (8) A, beta = 99.65 (3) degrees; space group P2(1); Z = 2] shows the presence of six intramolecular NH...CO hydrogen bonds, with formation of four turns (three of type I and one of type III) and two C16 ring structures. All peptide units are trans. The solution structure, as found by nmr, indicates that, at room temperature, the peptide is conformationally homogeneous; the structure determined is perfectly symmetrical and topologically similar to that found in the solid state. The cyclodecapeptide exhibits similar biological activity to cyclolinopeptide A.
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Affiliation(s)
- F Rossi
- Dipartimento di Chimica, Università di Napoli Federico II, Italy
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31
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Saviano M, Isernia C, Rossi F, Di Blasio B, Iacovino R, Mazzeo M, Pedone C, Benedetti E. Solid state structural analysis of the cyclooctapeptide cyclo- (Pro1-Pro-Phe-Phe-Ac6c-Ile-D-Ala-Val8). Biopolymers 2000; 53:189-99. [PMID: 10679623 DOI: 10.1002/(sici)1097-0282(200002)53:2<189::aid-bip9>3.0.co;2-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A solid state analysis of the cyclic octapeptide c(-Pro(1)-Pro-Phe-Phe-Ac(6)c-Ile-D-Ala-Val(8)-) (C8-CLA), containing the Pro-Pro-Phe-Phe sequence, followed by the bulky helicogenic C(alpha,alpha)-dialkylated 1-aminocyclohexane-1-carboxylic acid (Ac(6)c) residue and a D-Ala residue in position 7, has been carried out by x-ray diffraction. The crystals, grown from a DMSO solution, are monoclinic, space group P2(1) with a = 13.458(3) A, b = 19. 404(5) A, c = 21.508(4) A, and beta = 90.83(6) degrees, with two independent cyclic molecules in the asymmetric unit, two DMSO molecules, and three water molecules. The structure has been solved using the half and bake procedure by Sheldrick, and refined to final R1 and wR2 indices of 0.0613 and 0.1534 for 9867 reflections with I > 2sigma(I). This cyclic peptide, a deletion analogue of the naturally occurring cyclic nonapeptide cyclolinopeptide A [c(Pro-Pro-Phe-Phe-Leu-Ile-Ile-Leu-Val), CLA] has been designed to study the influence of the ring size reduction on the conformational behavior of CLA and more in general to obtain structural information on asymmetric cyclic octapeptides. The compound exhibits, in the solid state, a "banana-twisted" conformation with a cis peptide bond located between the two proline residues. Five intramolecular H bonds stabilize the structure: one type VIa beta-turn, two consecutive type III/I beta-turns, one gamma-turn, and one C(16) bend. The structure has also been compared with either the solution structure previously reported by us and obtained by nmr and computational analysis, and with solid state structural data reported in the literature on cyclic octapeptides.
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Affiliation(s)
- M Saviano
- Centro di Studio di Biocristallografia del CNR, Dipartimento di Chimica, Università di Napoli, via Mezzocannone 4,80134, Napoli, Italy
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32
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Wu MG, Deem MW. Analytical rebridging Monte Carlo: Application to cis/trans isomerization in proline-containing, cyclic peptides. J Chem Phys 1999. [DOI: 10.1063/1.479952] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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33
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Zanotti G, Saviano M, Saviano G, Tancredi T, Rossi F, Pedone C, Benedetti E. Structure of cyclic peptides: the crystal and solution conformation of cyclo(Phe-Phe-Aib-Leu-Pro). THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 1998; 51:460-6. [PMID: 9650721 DOI: 10.1111/j.1399-3011.1998.tb00645.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A solid-state and solution conformation analyses of the cyclopentapeptide cyclo(Phe-Phe-Aib-Leu-Pro) has been carried out by X-ray diffraction and nuclear magnetic resonance techniques. The structure of the hexagonal crystals, grown from a methanol solution [a = b = 16.530(4) A, c = 21.356(9) A, space group P6(5), Z = 6], shows the presence of one intramolecular N-H ..O=C hydrogen bond with the formation of a gamma-turn (C7). The Aib3 residue, at the center of the gamma-turn, presents unexpected values of the torsion angles [phi = 70.5 degrees and psi = -73.8 degrees], which have been observed only once before for this helicogenic residue. A cis peptide bond occurs between Leu4 and Pro5; all other peptide bonds are trans. The overall conformation for the cyclopentapeptide with one cis-peptide bond on one side and an intramolecular gamma-turn on the opposite side results in an equatorial topology of the side-chains of the Phe1, Phe2 and Leu4 residues. Indeed, the Calpha-Cbeta and Cbeta-Cgamma bonds of these residues lie approximately in the mean plane of the cyclic ring system. The structure is compared with data in the literature on cyclic pentapeptides. In addition the Pro-Phe-Phe moiety shows a conformation similar to that observed in other larger cyclic bioactive peptides, which indicates a reduced number of conformations for this sequence. The solution study was carried out in three different solvent systems: chloroform, acetonitrile and methanol in the temperature interval 220-300 K. In all three solvents the room temperature spectra show that the peptide is conformationally nonhomogeneous. In acetonitrile at low temperatures it is possible to reduce the conformational equilibrium to two predominant conformers which differ for the cis-trans isomerism of the Leu4-Pro5 peptide bond.
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Affiliation(s)
- G Zanotti
- Centro di Studio sulla Chimica del Farmaco del C.N.R, Università di Roma La Sapienza, Italy
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34
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Kemmer H, Tripier D, Jouvenal K, Scriba D, Zanotti G, Maione AM, Ziegler K. Binding proteins for cyclic and linear oligopeptides in plasma membranes and the cytosol of rat hepatocytes. Biochem Pharmacol 1997; 54:481-90. [PMID: 9313775 DOI: 10.1016/s0006-2952(97)00208-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Using a cyclolinopeptide A analogue, the hydrophobic cyclic peptide c(-Ala-Lys-Pro-Phe-Phe-Ala-Lys-Pro-Phe-Phe-), termed CDP (cyclodecapeptide), as ligand in affinity chromatography, hepatocellular peptide binding proteins were isolated from the integral part of plasma membranes and the cytosol. The sequence of the isolated protein with MW of 50 kDa from the integral part of the plasma membrane fraction was identical to cytochrome P450 II C13 and cytochrome P450 II C22, whereas the sequence of the 54 kDa protein was identical to 3-hydroxyandrogen-UDP-glucuronosyltransferase. These proteins have also been described as binding proteins for bile acids. As shown in earlier studies, bile acids and CDP also compete for uptake into hepatocytes. In the cytosol, a further known bile acid binding protein, the glutathione-S-transferase (G-S-T) subunit Yb1, was isolated and sequenced as binding protein for CDP and also for a further cyclopeptide, the somatostatin analogue OO8, and a linear peptide with renin-inhibiting activity, EMD 55068. As shown in uptake studies using isolated basolateral plasma membrane vesicles, G-S-T was able to increase the uptake of EMD 51921, a linear peptide with renin-inhibiting potency, into the vesicles when the latter were preloaded with G-S-T. The binding of the substrate to the outside of the preloaded vesicles was not different than binding to unloaded vesicles. The maximal transport rate of the carrier-mediated/facilitated diffusion and the rate of permeation, however, were doubled in the presence of G-S-T, pointing to the involvement of intracellular binding proteins such as G-S-T in the unloading of the carrier protein and in the reduction of the free substrate concentration.
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Affiliation(s)
- H Kemmer
- Institut Für Pharmakologie und Toxikologie, Justus-Liebig-Universitat, Giessen, Germany
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35
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Cebrat M, Lisowski M, Siemion IZ, Zimecki M, Wieczorek Z. Sulfonated analogues of cyclolinopeptide A. Synthesis, immunosuppressive activity and CD studies. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 1997; 49:415-20. [PMID: 9211222 DOI: 10.1111/j.1399-3011.1997.tb00893.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Linear and cyclic analogues of cyclolinopeptide A (CLA) in which one or both phenylalanine residues in fragment Pro6-Pro7-Phe8-Phe9 were substituted by their sulfonated derivatives have been synthesized by SPPS method and cyclization with the BOP reagent. The peptides were examined for their immunosuppressive activity in the humoral and cellular immune response by PFC and DTH tests. All of the analogues retain some immunosuppressive activity of native CLA. Their CD spectra confirm that the optical activity of aromatic residues in CLA depends on their position in the peptide chain. Only the residue in position 8 seems to be optically active. CD spectrum of the cyclic analogue modified in position 9 is very similar to that of native CLA which correlates with its high biological activity. The chiroptical properties of the p-sulfonated Phe-residue are established.
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Affiliation(s)
- M Cebrat
- Faculty of Chemistry, University of Wrocław, Poland
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36
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Saviano M, Rossi F, Filizola M, Isernia C, Di Blasio B, Benedetti E, Pedone C, Siemion IZ, Pedyczak A. Bioactive peptides: conformational studies of [Tyr4] cyclolinopeptide A. Biopolymers 1995; 36:453-60. [PMID: 7578940 DOI: 10.1002/bip.360360408] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The solid state conformational analysis of [Tyr4] cyclolinopeptide A has been carried out by x-ray diffraction studies. The crystal structure of the monoclinic form, grown from a dioxane-water mixture [alpha = 9.849 (5) A, b = 20.752 (4) A, c = 16.728 (5) A, beta = 98.83 (3) degrees, space group P21, Z = 2], shows the presence of five intramolecular N-H...O = C hydrogen bonds, with formation of one C17 ring structure, one alpha-turn (C13), one inverse gamma-turn (C7), and two beta-turns (C10, one of type III and one of type I). The Pro1-Pro2 peptide unit is cis (omega = 5 degrees), all others are trans. The structure is almost superimposable with that of cyclolinopeptide A. The rms deviation for the atoms of the backbones is on the average 0.33 A.
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Affiliation(s)
- M Saviano
- CNR, Università di Napoli Federico II, Dipartimento di Chimica, Italy
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Rossi F, Saviano M, Di Blasio B, Zanotti G, Maione AM, Tancredi T, Pedone C. Bioactive peptides: solid state, solution and molecular dynamics studies of a cyclolinopeptide A-related cystinyl cyclopentapeptide. Biopolymers 1994; 34:273-84. [PMID: 8142593 DOI: 10.1002/bip.360340213] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The conformational analysis of [sequence: see text] the disulphide cyclopeptide-related cyclolinopeptide A, has been carried out by solid state methods using x-ray diffraction techniques, in solution by nmr, CD, ir spectroscopies, and by molecular dynamics (MD) analysis. The structure of the monoclinic form, obtained from ethanol (a = 11.303(2) A, b = 14.467(8) A, c = 12.355(2) A, beta(degree) = 109.40(1), space group P2(1), Z = 2) presents two transannular H bonds with the formation of one type VIa beta-turn involving the C = O of the urethane moiety and the Phe3 NH, and an intramolecular H bond between the C = O of urethane group and the Phe4 NH. In the solid state all the peptide bonds are in the trans configuration with the exception of a cis peptide bond occurring between the Cys1 and Pro2 residues; the linkage S-S assumes right-handed chirality. The conformational study in solution by nmr spectroscopy indicates that the peptide is very flexible and that some conformer families are present at room temperature both in polar and apolar solvents. CD studies confirm that this cyclic system tends to give rise to a complex mixture of quasi-isoenergetic conformations, favored by the flexibility of the disulphide bridge and by the isomerism of the Xxx-Pro bond. MD studies carried out in vacuo and in solution shows that the structure determined by solid state represents a energy minimum. All hydrogen bonds found in the crystalline state are correctly reproduced in vacuo and in solution simulations.
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Affiliation(s)
- F Rossi
- Centro di Studio di Biocristallografia del CNR, CIRPEB, Università di Napoli, Italy
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38
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39
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Zanotti G, Maione A, Rossi F, Saviano M, Pedone C, Tancredi T. Bioactive peptides: conformational study of a cystinyl cycloheptapeptide in its free and calcium complexed forms. Biopolymers 1993; 33:1083-91. [PMID: 8343586 DOI: 10.1002/bip.360330710] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The disulphide bridged heptapeptide Boc-Cys-Val-Pro-Pro-Phe-Phe-Cys-OMe has been synthesized by classical solution methods. An ion binding study showed the peptide's ability to complex calcium ions with definite stoichiometry. The solution conformation of the peptide in its free and calcium-complexed form has been investigated by CD and nmr. The model structure derived from nmr data has been energy minimized and the resulting structure investigated by molecular dynamics simulation in water. The structure of the equimolar peptide/Ca2+ complex in acetonitrile at room temperature shows the presence of two transannular hydrogen bonds, with the formation of two ring structures of the C10 (type VIa) and C14 type. One peptide unit (Pro-Pro) is cis, all others are trans.
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Affiliation(s)
- G Zanotti
- Centro di Studi Chimica del Farmaco del CNR, Roma, Italy
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40
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Di Blasio B, Pavone V, Lombardi A, Pedone C, Benedetti E. Noncoded residues as building blocks in the design of specific secondary structures: symmetrically disubstituted glycines and beta-alanine. Biopolymers 1993; 33:1037-49. [PMID: 8343584 DOI: 10.1002/bip.360330706] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Structural changes can be induced in a peptide by selective substitution of coded alpha-amino acid residues by noncoded alpha-amino acid residues and the consequent production of analogues with modified structure and conformational preferences. In this review article we summarize the solid state structural results and the conformational preferences of two classes of "building blocks": (a) the linear and cyclic symmetrically alpha, alpha-disubstituted glycines in which either two identical n-alkyl groups replace the hydrogen atoms of the glycine residue or a cyclic aliphatic side-chain system is formed by linking the two alpha-carbon side chains, respectively; and (b) the beta-alanine residue. Examples, whenever possible, of the use of these residues for the elucidation of the bioactive conformation in the appropriate biological systems will be given.
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Affiliation(s)
- B Di Blasio
- Department of Chemistry, University of Naples Federico II, Italy
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41
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Ernst RR. Nuclear Magnetic Resonance Fourier Transform Spectroscopy (Nobel Lecture). ACTA ACUST UNITED AC 1992. [DOI: 10.1002/anie.199208053] [Citation(s) in RCA: 122] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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42
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Saviano M, Rossi F, Pavone V, Di Blasio B, Pedone C. Molecular dynamics simulation in vacuo and in solution of [Aib5,6-D-Ala8] cyclolinopeptide A: a conformational and comparative study. J Biomol Struct Dyn 1992; 9:1045-60. [PMID: 1637502 DOI: 10.1080/07391102.1992.10507978] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The conformation of a Cyclolinopeptide A analogue, c-(Pro-Pro-Phe-Phe-Aib-Aib-Ile-D-Ala-Val), has been investigated by means of molecular dynamics simulations, in various molecular environments. The molecular dynamics results are compared with that obtained for Cyclolinopeptide A and a detailed analysis of the different behaviour for the two compounds is reported. A complete analysis of hydrogen bonds is presented.
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Affiliation(s)
- M Saviano
- Centro di Studio di Biocristallografia del C.N.R., Dipartimento di Chimica, Napoli, Italy
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43
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Saviano M, Aida M, Corongiu G. Molecular dynamics simulation in vacuo and in solution of cyclolinopeptide A: a conformational study. Biopolymers 1991; 31:1017-24. [PMID: 1782353 DOI: 10.1002/bip.360310811] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The conformation of cyclolinopeptide A [c-(Pro-Pro-Phe-Phe-Leu-Ile-Ile-Leu-Val)], a naturally occurring peptide with remarkable cytoprotective activity, has been investigated by means of molecular dynamics simulations in various molecular environments. Structural and dynamical properties have been analyzed and compared with those experimentally determined. A detailed analysis of hydrogen bonds is reported.
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Affiliation(s)
- M Saviano
- IBM Corporation, Scientific Engineering Computations, Department 48B/MS428, Kingston, New York 12401
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44
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Tancredi T, Benedetti E, Grimaldi M, Pedone C, Rossi F, Saviano M, Temussi PA, Zanotti G. Ion binding of cyclolinopeptide A: an NMR and CD conformational study. Biopolymers 1991; 31:761-7. [PMID: 1932572 DOI: 10.1002/bip.360310621] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
CD and nmr techniques have been used to study, in acetonitrile solution, the ion-complexing capability of cyclolinopeptide A (CLA), a cyclic nonapeptide of sequence cyclo-(Pro-Pro-Phe-Phe-Leu-Ile-Ile-Leu-Val) endowed with remarkable cytoprotective ability in vitro, and the conformation of the Ba(2+)/CLA complex. At room temperature, CLA in acetonitrile shows a proton nmr spectrum characteristic of the coexistence of many different conformers in intermediate exchange. The backbone contains a cis Pro-Pro bond, with all other peptide bonds in the trans conformation. CLA binds Ba2+ more tightly than the other cations studied, namely K+, Na+, Mg2+, and Ca2+; CD data are indicative of the presence of both 1:2 (sandwich) and 1:1 (equimolar) type complexes, depending on the Ba2+ ion concentration, whereas nmr data are consistent with an equimolar form. The relevant conformational features of the equimolar Ba2+/CLA complex are that the backbone contains all trans peptide bonds, a type I 6----3 beta-turn and a 3----1 gamma-turn (or a distorted 3----9 beta-turn). The global shape of the complexed peptide can be described as a bowl, with the concave (polar) side hosting Ba2+ and the convex side predominantly apolar.
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Affiliation(s)
- T Tancredi
- Istituto Chimica MIB del CNR, Arco Felice, Italy
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45
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Gilon C, Halle D, Chorev M, Selinger Z, Byk G. Backbone cyclization: A new method for conferring conformational constraint on peptides. Biopolymers 1991; 31:745-50. [PMID: 1718473 DOI: 10.1002/bip.360310619] [Citation(s) in RCA: 160] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
This article describes a new concept of medium- and long-range cyclization of peptides through "backbone cyclization." In this approach, conformational constraints are conferred on a peptide by linking omega-substituted alkylidene chains replacing N(alpha) or C(alpha) hydrogens in a peptidic backbone. Backbone cyclization, which is divided into N-backbone and C-backbone cyclizations, allow for new modes of cyclization in addition to the classical ones that are limited to cyclization through the side chains and/or the amino or carboxyl terminal groups. The article also describes the application of the N-backbone cyclization to the active region of substance P. Conformational constraints of this peptide by the classical cyclization modes led to inactive analogues whereas N-backbone cyclization provided an active, selective, and metabolically stable analogue.
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Affiliation(s)
- C Gilon
- Department of Organic Chemistry, Hebrew University of Jerusalem, Israel
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46
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Neela BS, Manjula MV, Ramakumar S, Balasubramanian D, Viswamitra MA. Conformation of cyclolinopeptide dihydrate: an antamanide analogue. Biopolymers 1990; 29:1499-501. [PMID: 2361160 DOI: 10.1002/bip.360291017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- B S Neela
- Department of Physics, Indian Institute of Science, Bangalore, India
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47
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Hofmann M, Gehrke M, Bermel W, Kessler H. Proton-detected C,H correlation NMR techniques for the complete assignment of all proton and carbon resonances of a cyclic peptide. MAGNETIC RESONANCE IN CHEMISTRY : MRC 1989; 27:877-886. [PMID: 34034434 DOI: 10.1002/mrc.1260270911] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/1989] [Accepted: 05/15/1989] [Indexed: 06/12/2023]
Abstract
The assignment of the proton and carbon spectra of the cyclic peptide cyclo(-Phe1 -Pro2 -Thr3 -Lys(Z)4 -Trp5 -Phe6 -) was accomplished by the application of multiple quantum proton-detected heteronuclear correlation spectroscopy. Since the proton spectrum shows severe overlap, the carbon chemical shifts were used to disentangle the proton resonances. The methodology described is useful even in cases where only limited quantities of materials are available. The combination of (i) a proton decoupled C,H correlation spectrum and (ii) a (not decoupled) H-relayed C,H correlation gave the assignments of all CHn groups. The non-protonated carbons, i.e. the carbonyl carbons of the peptide bond, were assigned with a C,H correlation optimized for long-range couplings, an experiment that also gave helpful information about the conformational features of the hexapeptide. The cyclic peptide contains a Phe-Pro cis-peptide bond forming a βVI-like bend and a β-turn about the amino acids Thr-Lys-Trp-Phe. Although the conventional discussion of NMR parameters indicates a strong preference for one conformation, the quantitative evaluation of NOE-derived distances in restrained MD calculations proves that the type of β-turn in the last-mentioned region is not unique. Whereas the MD calculations converge to a βII' turn, the vicinal proton coupling constants are in better agreement with type βI. Thus a dynamic equilibrium of the backbone is proposed.
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Affiliation(s)
- Mechtild Hofmann
- Institut für Organische Chemie, Johann Wolfgang Goethe-Universität, Niederurseler Hang, D-6000 Frankfurt 50, FRG
| | - Matthias Gehrke
- Institut für Organische Chemie, Johann Wolfgang Goethe-Universität, Niederurseler Hang, D-6000 Frankfurt 50, FRG
| | - Wolfgang Bermel
- Institut für Organische Chemie, Johann Wolfgang Goethe-Universität, Niederurseler Hang, D-6000 Frankfurt 50, FRG
| | - Horst Kessler
- Institut für Organische Chemie, Johann Wolfgang Goethe-Universität, Niederurseler Hang, D-6000 Frankfurt 50, FRG
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48
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Raghothama S, Ramakrishnan C, Balasubramanian D, Balaram P. Conformational analysis of cyclolinopeptide A, a cyclic nonapeptide: nuclear Overhauser effect and energy minimization studies. Biopolymers 1989; 28:573-88. [PMID: 2713453 DOI: 10.1002/bip.360280204] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The conformation of cyclolinopeptide A [cyclo(Pro-Pro-Phe-Phe-Leu-Ile-Ile-Leu-Val)], a naturally occurring cyclic nonapeptide has been investigated in dimethylsulfoxide solution by 270 MHz 1H-nmr. A complete assignment of all C alpha H and NH resonances has been accomplished using two-dimensional correlated spectroscopy and nuclear Overhauser effects (NOEs). Analysis of interresidue NOEs and JHNC alpha H values permit construction of a molecular model for the cyclic peptide backbone. The crude model derived from nmr has been used as a starting point for energy minimization, which yields a refined structure largely compatible with nmr observations. The major features of the conformation of cyclolinopeptide A are a Type VI beta-turn centered at Pro(1)-Pro(2), with a cis peptide bond between these residues and a gamma-turn (C7 structure) centered at Ile(6). Two intramolecular hydrogen bonds Val(9) CO--Phe(3)NH (4----1) and Leu(5) CO--Ile(7)NH (3----1) are observed in the low-energy conformation. The limited solvent accessibility observed for the Val(9) and Leu(5) NH groups in the nmr studies are rationalized in terms of steric shielding.
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49
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Zanotti G, Tancredi T, Rossi F, Benedetti E, Pedone C, Temussi P. Ala analogues of the cyclolinopeptide A. Biopolymers 1989; 28:371-83. [PMID: 2720114 DOI: 10.1002/bip.360280135] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Analogues of cyclolinopeptide A, due to the replacement of each amino acid in the Pro1-Pro2-Phe3-Phe4 sequences with an L-Ala residue, were synthesized by classical method in solution. Mixed anhydride and N,N'-dicyclohexylcarbodiimide coupling methods have been used for the synthesis of both linear and cyclic peptides. The products were characterized by Rf values and uv spectra, as well as by fast atom bombardment spectroscopy. 1H-nmr studies on [Ala2] analogues are also reported. Preliminary data in CDCl3 solution, at low temperature, seems more promising.
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50
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Kessler H, Haupt A, Schudok M, Ziegler K, Frimmer M. Peptide conformations--49(1): synthesis and structure-activity relationships of side chain modified peptides of cyclo(-D-Pro-Phe-Thr-Lys-Trp-Phe.). INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1988; 32:183-93. [PMID: 2907513 DOI: 10.1111/j.1399-3011.1988.tb00933.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cyclic hexapeptide analogues representing the modified retro sequence of the amino acid residues 7-11 of natural somatostatin are known to protect liver cells from phalloidin poisoning. To determine the influence of steric, lipophilic, and charge effects on (a) the conformation of the backbone and the aromatic side chains and (b) the biological response, the side chains of Phe2, Lys4, and Phe6 of cyclo(-D-Pro1-Phe2-Thr3-Lys(Z)4-Trp5-Phe6-), 1a, one of the most active peptides found so far, were modified by various residues. The discussion of conformationally relevant parameters proves that neither backbone conformations nor populations of aromatic side chain rotamers were altered by these substitutions. The potency of these derivatives in a cytoprotection assay varies by at most one order of magnitude (more or less active than the parent peptide 1a). A qualitative evaluation of lipophilic, steric, and charge effects reveals the dominance of lipophilic effects of aromatic residues; the most potent compounds contain aromatic substructures in the side chain of Lys4.
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Affiliation(s)
- H Kessler
- Institute of Organic Chemistry, Johann Wolfgang Goethe-University, Frankfurt, Federal Republic of Germany
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