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Singh J, Joshi S, Mumtaz S, Maurya N, Ghosh I, Khanna S, Natarajan VT, Mukhopadhyay K. Enhanced Cationic Charge is a Key Factor in Promoting Staphylocidal Activity of α-Melanocyte Stimulating Hormone via Selective Lipid Affinity. Sci Rep 2016; 6:31492. [PMID: 27526963 PMCID: PMC4985751 DOI: 10.1038/srep31492] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 07/20/2016] [Indexed: 02/07/2023] Open
Abstract
The steady rise in antimicrobial resistance poses a severe threat to global public health by hindering treatment of an escalating spectrum of infections. We have previously established the potent activity of α-MSH, a 13 residue antimicrobial peptide, against the opportunistic pathogen Staphylococcus aureus. Here, we sought to determine whether an increase in cationic charge in α-MSH could contribute towards improving its staphylocidal potential by increasing its interaction with anionic bacterial membranes. For this we designed novel α-MSH analogues by replacing polar uncharged residues with lysine and alanine. Similar to α-MSH, the designed peptides preserved turn/random coil conformation in artificial bacterial mimic 1,2-dimyristoyl-sn-glycero-3-phosphocholine:1,2-dimyristoyl-sn-glycero-3-phospho-rac-(1-glycerol) (7:3, w/w) vesicles and showed preferential insertion in the hydrophobic core of anionic membranes. Increased cationic charge resulted in considerable augmentation of antibacterial potency against MSSA and MRSA. With ~18-fold better binding than α-MSH to bacterial mimic vesicles, the most charged peptide KKK-MSH showed enhanced membrane permeabilization and depolarization activity against intact S. aureus. Scanning electron microscopy confirmed a membrane disruptive mode of action for KKK-MSH. Overall, increasing the cationic charge improved the staphylocidal activity of α-MSH without compromising its cell selectivity. The present study would help in designing more effective α-MSH-based peptides to combat clinically relevant staphylococcal infections.
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Affiliation(s)
- Jyotsna Singh
- Antimicrobial Research Laboratory, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi-110067, India
| | - Seema Joshi
- Antimicrobial Research Laboratory, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi-110067, India
| | - Sana Mumtaz
- Antimicrobial Research Laboratory, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi-110067, India
| | - Nancy Maurya
- Biochemistry and Environmental Toxicology Laboratory, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi-110067, India
| | - Ilora Ghosh
- Biochemistry and Environmental Toxicology Laboratory, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi-110067, India
| | - Shivangi Khanna
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi-110020, India
| | - Vivek T Natarajan
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi-110020, India
| | - Kasturi Mukhopadhyay
- Antimicrobial Research Laboratory, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi-110067, India
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2
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Singh A, Dirain M, Witek R, Rocca JR, Edison AS, Haskell-Luevano C. Structure-activity relationships of peptides incorporating a bioactive reverse-turn heterocycle at the melanocortin receptors: identification of a 5800-fold mouse melanocortin-3 receptor (mMC3R) selective antagonist/partial agonist versus the mouse melanocortin-4 receptor (mMC4R). J Med Chem 2013; 56:2747-63. [PMID: 23432160 PMCID: PMC3652311 DOI: 10.1021/jm301253y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The melanocortin-3 (MC3) and melanocortin-4 (MC4) receptors regulate energy homeostasis, food intake, and associated physiological conditions. The melanocortin-4 receptor (MC4R) has been studied extensively. Less is known about specific physiological roles of the melanocortin-3 receptor (MC3R). A major obstacle to this lack of knowledge is attributed to a limited number of identified MC3R selective ligands. We previously reported a spatial scanning approach of a 10-membered thioether-heterocycle ring incorporated into a chimeric peptide template that identified a lead nM MC4R ligand. Upon the basis of those results, 17 compounds were designed and synthesized that focused upon modification in the pharmacophore domain. Notable results include the identification of a 0.13 nM potent 5800-fold mMC3R selective antagonist/slight partial agonist versus a 760 nM mMC4R full agonist (ligand 11). Biophysical experiments (two-dimensional (1)H NMR and computer-assisted molecular modeling) of this ligand resulted in the identification of an inverse γ-turn secondary structure in the ligand pharmacophore domain.
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Affiliation(s)
- Anamika Singh
- Departments of Medicinal Chemistry and Pharmacodynamics University of Florida, Gainesville, FL 32610, USA
- Department of Medicinal Chemistry University of Minnesota, Minneapolis, MN 55455, USA
| | - Marvin Dirain
- Departments of Medicinal Chemistry and Pharmacodynamics University of Florida, Gainesville, FL 32610, USA
| | - Rachel Witek
- Departments of Medicinal Chemistry and Pharmacodynamics University of Florida, Gainesville, FL 32610, USA
| | - James R. Rocca
- McKnight Brain Institute, University of Florida, Gainesville, FL 32611
| | - Arthur S Edison
- Department of Biochemistry & Molecular Biology and National High Magnetic Field Laboratory, University of Florida, Gainesville, FL 32610, USA
| | - Carrie Haskell-Luevano
- Departments of Medicinal Chemistry and Pharmacodynamics University of Florida, Gainesville, FL 32610, USA
- Department of Medicinal Chemistry University of Minnesota, Minneapolis, MN 55455, USA
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3
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Ji HX, Zou YL, Duan JJ, Jia ZR, Li XJ, Wang Z, Li L, Li YW, Liu GY, Tong MQ, Li XY, Zhang GH, Dai XR, He L, Li ZY, Cao C, Yang Y. The synthetic melanocortin (CKPV)2 exerts anti-fungal and anti-inflammatory effects against Candida albicans vaginitis via inducing macrophage M2 polarization. PLoS One 2013; 8:e56004. [PMID: 23457491 PMCID: PMC3573073 DOI: 10.1371/journal.pone.0056004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 01/04/2013] [Indexed: 12/30/2022] Open
Abstract
In this study, we examined anti-fungal and anti-inflammatory effects of the synthetic melanocortin peptide (Ac-Cys-Lys-Pro-Val-NH2)2 or (CKPV)2 against Candida albicans vaginitis. Our in vitro results showed that (CKPV)2 dose-dependently inhibited Candida albicans colonies formation. In a rat Candida albicans vaginitis model, (CKPV)2 significantly inhibited vaginal Candida albicans survival and macrophages sub-epithelial mucosa infiltration. For mechanisms study, we observed that (CKPV)2 inhibited macrophages phagocytosis of Candida albicans. Meanwhile, (CKPV)2 administration inhibited macrophage pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) release, while increasing the arginase activity and anti-inflammatory cytokine IL-10 production, suggesting macrophages M1 to M2 polarization. Cyclic AMP (cAMP) production was also induced by (CKPV)2 administration in macrophages. These above effects on macrophages by (CKPV)2 were almost reversed by melanocortin receptor-1(MC1R) siRNA knockdown, indicating the requirement of MC1R in the process. Altogether, our results suggest that (CKPV)2 exerted anti-fungal and anti-inflammatory activities against Candida albicans vaginitis probably through inducing macrophages M1 to M2 polarization and MC1R activation.
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Affiliation(s)
- Hai-xia Ji
- State Key Laboratory of Natural Medicines, Academic Institute of Pharmaceutical Science, China Pharmaceutical University, Nanjing, Jiangsu, People’s Republic of China
| | - Yu-lian Zou
- State Key Laboratory of Natural Medicines, Academic Institute of Pharmaceutical Science, China Pharmaceutical University, Nanjing, Jiangsu, People’s Republic of China
| | - Jing-jing Duan
- State Key Laboratory of Natural Medicines, Academic Institute of Pharmaceutical Science, China Pharmaceutical University, Nanjing, Jiangsu, People’s Republic of China
| | - Zhi-rong Jia
- State Key Laboratory of Natural Medicines, Academic Institute of Pharmaceutical Science, China Pharmaceutical University, Nanjing, Jiangsu, People’s Republic of China
| | - Xian-jing Li
- State Key Laboratory of Natural Medicines, Academic Institute of Pharmaceutical Science, China Pharmaceutical University, Nanjing, Jiangsu, People’s Republic of China
| | - Zhuo Wang
- State Key Laboratory of Natural Medicines, Academic Institute of Pharmaceutical Science, China Pharmaceutical University, Nanjing, Jiangsu, People’s Republic of China
| | - Li Li
- Department of Pharmacology, Department of Physiology, Guilin Medical University, Guilin, Guangxi, People’s Republic of China
| | - Yong-wen Li
- Department of Pharmacology, Department of Physiology, Guilin Medical University, Guilin, Guangxi, People’s Republic of China
| | - Gen-yan Liu
- Department of Laboratory Medicine, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China
| | - Ming-Qing Tong
- Department of Laboratory Medicine, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China
| | - Xiao-yi Li
- Hefei Zhaoke Pharmaceutical, Hefei, People’s Republic of China
| | - Guo-hui Zhang
- Hefei Zhaoke Pharmaceutical, Hefei, People’s Republic of China
| | - Xiang-rong Dai
- Hefei Zhaoke Pharmaceutical, Hefei, People’s Republic of China
| | - Ling He
- State Key Laboratory of Natural Medicines, Academic Institute of Pharmaceutical Science, China Pharmaceutical University, Nanjing, Jiangsu, People’s Republic of China
| | - Zhi-yu Li
- State Key Laboratory of Natural Medicines, Academic Institute of Pharmaceutical Science, China Pharmaceutical University, Nanjing, Jiangsu, People’s Republic of China
- * E-mail: (YY); (CC); (ZL)
| | - Cong Cao
- Neuroscience Institute, Soochow University, Soochow, Jiangsu, People’s Republic of China
- * E-mail: (YY); (CC); (ZL)
| | - Yong Yang
- State Key Laboratory of Natural Medicines, Academic Institute of Pharmaceutical Science, China Pharmaceutical University, Nanjing, Jiangsu, People’s Republic of China
- * E-mail: (YY); (CC); (ZL)
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Seo MD, Won HS, Kim JH, Mishig-Ochir T, Lee BJ. Antimicrobial peptides for therapeutic applications: a review. Molecules 2012; 17:12276-86. [PMID: 23079498 PMCID: PMC6268056 DOI: 10.3390/molecules171012276] [Citation(s) in RCA: 331] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 10/08/2012] [Accepted: 10/17/2012] [Indexed: 11/16/2022] Open
Abstract
Antimicrobial peptides (AMPs) have been considered as potential therapeutic sources of future antibiotics because of their broad-spectrum activities and different mechanisms of action compared to conventional antibiotics. Although AMPs possess considerable benefits as new generation antibiotics, their clinical and commercial development still have some limitations, such as potential toxicity, susceptibility to proteases, and high cost of peptide production. In order to overcome those obstacles, extensive efforts have been carried out. For instance, unusual amino acids or peptido-mimetics are introduced to avoid the proteolytic degradation and the design of short peptides retaining antimicrobial activities is proposed as a solution for the cost issue. In this review, we focus on small peptides, especially those with less than twelve amino acids, and provide an overview of the relationships between their three-dimensional structures and antimicrobial activities. The efforts to develop highly active AMPs with shorter sequences are also described.
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Affiliation(s)
- Min-Duk Seo
- College of Pharmacy, Ajou University, Suwon 443-749, Korea
| | - Hyung-Sik Won
- Department of Biotechnology, College of Biomedical and Health Science, Konkuk University, Chungju, Chungbuk 380-701, Korea
| | - Ji-Hun Kim
- Center for Structural Biology and Departments of Biochemistry and Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | | | - Bong-Jin Lee
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
- Author to whom correspondence should be addressed; ; Tel.: +82-2-880-7869; Fax: +82-2-872-3632
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5
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Lee JY, Kim YC. Combinatorial Library Synthesis and Biological Evaluation of Pyrazolo[4,3-e][1,4]diazepine as a Potential Privileged Structure. ChemMedChem 2009; 4:733-7. [DOI: 10.1002/cmdc.200800453] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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6
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Capsoni F, Ongari A, Colombo G, Turcatti F, Catania A. The synthetic melanocortin (CKPV)2 exerts broad anti-inflammatory effects in human neutrophils. Peptides 2007; 28:2016-22. [PMID: 17850921 DOI: 10.1016/j.peptides.2007.08.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Revised: 08/02/2007] [Accepted: 08/03/2007] [Indexed: 11/21/2022]
Abstract
Natural melanocortin peptides exert broad effects on the host and they have remarkable therapeutic potential. However, successful use of melanocortins as therapeutic agents depends on the design of molecules that have more stable pharmacological profiles. The synthetic peptide (CKPV)(2), based on the C-terminal sequence of alpha-melanocyte stimulating hormone (alpha-MSH), has anti-tumor necrosis factor-alpha (TNF-alpha) effects in vitro and in vivo and is a promising candidate to treat inflammation. Because neutrophil activity is a major target for anti-inflammatory therapies, we determined whether (CKPV)(2) modulates human neutrophil functions in vitro. Incubation of freshly-separated human neutrophils with 10(-12)-10(-6)M (CKPV)(2) significantly inhibited activities relevant to the inflammatory reaction. Neutrophil migration toward the two chemoattractants interleukin 8 (IL-8) and N-formyl-methionyl-leucyl-phenylalanine (fMLP) was significantly inhibited by (CKPV)(2). (CKPV)(2) also inhibited reactive oxygen intermediate (ROI) production induced by phorbol 12-myristate 13-acetate (PMA), but not that induced by fMLP. Because these effects of (CKPV)(2) were abolished by the adenylyl cyclase inhibitor 2',5'-dideoxyadenosine (ddAdo), they appear to be cAMP-dependent. Finally, the peptide reduced lipopolysaccharide (LPS)-stimulated expression of TNF-alpha, interleukin-1beta (IL-1beta), interleukin-8 (IL-8), and intercellular adhesion molecule 1 (ICAM-1), as well as TNF-alpha protein release in cell supernatants. The data indicate that (CKPV)(2) modulates broad cAMP-dependent, anti-inflammatory pathways in human neutrophils.
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Affiliation(s)
- Franco Capsoni
- Rheumatology Unit, Istituto Ortopedico Galeazzi IRCCS, University of Milan, Milan, Italy
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7
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Spencer JD, Gibbons NCJ, Rokos H, Peters EMJ, Wood JM, Schallreuter KU. Oxidative stress via hydrogen peroxide affects proopiomelanocortin peptides directly in the epidermis of patients with vitiligo. J Invest Dermatol 2007; 127:411-20. [PMID: 16946714 DOI: 10.1038/sj.jid.5700538] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The human skin holds the capacity for autocrine processing of the proopiomelanocortin (POMC)-derived peptides. Recent data demonstrated the presence and functionality of ACTH, alpha- and beta-melanocyte-stimulating hormone (MSH), and beta-endorphin in the regulation of skin pigmentation, and a role has been put forward for alpha-MSH as an effective antioxidant. In patients with vitiligo, decreased epidermal POMC processing and low alpha-MSH levels were documented previously. These patients accumulate hydrogen peroxide (H2O2) in the 10(-3) M range in their epidermis. Therefore, we examined the involvement of H2O2 on POMC-derived peptides as possible targets for oxidation by this reactive oxygen species. To address this, we employed immunofluorescence labelling, dot blot analysis, Fourier transform Raman spectroscopy, functionality studies, and computer simulation of the peptide structures. We demonstrate H2O2-mediated oxidation of epidermal ACTH, alpha-MSH, and beta-endorphin in vitiligo owing to oxidation of methionine residues in the sequences of these peptides. Moreover, we show that oxidized beta-endorphin loses its function in the promotion of pigmentation in melanocytes. These changes are reversible upon the reduction of H2O2 levels by a pseudocatalase PC-KUS. Moreover, oxidation of alpha-MSH can be prevented by the formation of a 1:1 complex with the abundant cofactor (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin. Thus, using vitiligo, we demonstrate that H2O2 can affect pigmentation via epidermal POMC peptide redox homeostasis.
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Affiliation(s)
- Jennifer D Spencer
- Clinical and Experimental Dermatology/Department of Biomedical Sciences, University of Bradford, Bradford, UK
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8
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Chen M, Georgeson KE, Harmon CM, Haskell-Luevano C, Yang Y. Functional characterization of the modified melanocortin peptides responsible for ligand selectivity at the human melanocortin receptors. Peptides 2006; 27:2836-45. [PMID: 16730390 DOI: 10.1016/j.peptides.2006.04.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2006] [Revised: 04/14/2006] [Accepted: 04/17/2006] [Indexed: 11/24/2022]
Abstract
The melanocortin system plays an important role in energy homeostasis as well as skin pigmentation, steroidogenesis and exocrine gland function. In this study, we examined eight Ac-His-Phe-Arg-Trp-NH(2) tetrapeptides that were modified at the Phe position and pharmacologically characterized their activities at the human MCR wild-types and their mutants. Our results indicate that at the hMC1R, all D stereochemical modified residues at the Phe position of peptides increase cAMP production in a dose-dependent manner. At the hMC3R, the DPhe peptide dose dependently increases cAMP production but all other three tetrapeptides were not. At the hMC4R, both the DPhe and DNal(1') peptides induce cAMP production. However, both DTyr and DNal(2') were not able to induce cAMP production. Further studies indicated that at the hMC1R M128L mutant receptor, the all D-configured tetrapeptides reduce their potencies as compared to that of hMC1R wild-type. However, at the hMC3R and hMC4R L165M and L133M mutant receptors, the DNal(2') and DTyr tetrapeptides possess agonist activity. These findings indicate that DPhe in tetrapeptide plays an important role in ligand selectivity and specific residue TM3 of the melanocortin receptors is crucial for ligand selectivity.
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Affiliation(s)
- Min Chen
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL 35233, USA
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9
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Gatti S, Carlin A, Sordi A, Leonardi P, Colombo G, Fassati LR, Lipton JM, Catania A. Inhibitory Effects of the Peptide (CKPV)2 on Endotoxin-Induced Host Reactions. J Surg Res 2006; 131:209-14. [PMID: 16413580 DOI: 10.1016/j.jss.2005.08.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2005] [Revised: 07/29/2005] [Accepted: 08/04/2005] [Indexed: 11/19/2022]
Abstract
BACKGROUND alpha-Melanocyte stimulating hormone (alpha-MSH) is an endogenous peptide that has remarkable anti-inflammatory and antimicrobial effects. These activities have been traced to the C-terminal tripeptide Lys-Pro-Val (KPV). A dimer composed of two KPV sequences connected with a Cys-Cys linker, (CKPV)2, is currently under clinical investigation for antimicrobial use. The present research was designed to evaluate effects of (CKPV)(2) on endotoxin-induced host reactions in vitro and in vivo. MATERIALS AND METHODS Effects of (CKPV)2, KPV, and [Nle4-dPhe7]-alpha-MSH (NDP-alpha-MSH) on tumor necrosis factor alpha (TNF-alpha) production were determined: 1) in human peripheral blood mononuclear cells (PBMC) stimulated with lipopolysaccharide (LPS) in vitro, and 2) in rats injected with LPS i.v. and sacrificed at 1 h. In additional experiments, dialysis peritonitis was induced in rats by adding LPS to dialysis fluid. Net ultrafiltrate was calculated and concentrations of nitrite (NO2-) and TNF-alpha were measured in blood and peritoneal fluid at 7 h. RESULTS (CKPV)2 inhibited TNF-alpha production by LPS-stimulated human PBMC. This small peptide was as effective as NDP-alpha-MSH and more potent than KPV. Similar effectiveness was observed in vivo: 1 h after LPS injection, the large increase in circulating TNF-alpha was markedly reduced by (CKPV)2 treatment. In LPS-induced peritonitis, (CKPV)2 restored net ultrafiltrate to control values and significantly inhibited concentrations of TNF-alpha and NO2- both in plasma and in dialysate. CONCLUSIONS The remarkable capacity of (CKPV)2 to inhibit endotoxin-induced host reactions suggests that it may be useful in treatment of inflammatory disorders.
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Affiliation(s)
- Stefano Gatti
- Department of Liver Transplantation, Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Milano, Italy
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10
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Fernandez RM, Vieira RFF, Nakaie CR, Lamy MT, Ito AS. Acid-base titration of melanocortin peptides: evidence of Trp rotational conformers interconversion. Biopolymers 2005; 80:643-50. [PMID: 15657882 DOI: 10.1002/bip.20210] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Tryptophantime-resolved fluorescence was used to monitor acid-base titration properties of alpha-melanocyte stimulating hormone (alpha-MSH) and the biologically more potent analog [Nle4, D-Phe7]alpha -MSH (NDP-MSH), labeled or not with the paramagnetic amino acid probe 2,2,6,6-tetramthylpiperidine-N-oxyl-4-amino-4-carboxylic acid (Toac). Global analysis of fluorescence decay profiles measured in the pH range between 2.0 and 11.0 showed that, for each peptide, the data could be well fitted to three lifetimes whose values remained constant. The less populated short lifetime component changed little with pH and was ascribed to Trp g+ chi1 rotamer, in which electron transfer deactivation predominates over fluorescence. The long and intermediate lifetime preexponential factors interconverted along that pH interval and the result was interpreted as due to interconversion between Trp g- and trans chi1 rotamers, driven by conformational changes promoted by modifications in the ionization state of side-chain residues. The differences in the extent of interconversion in alpha-MSH and NDP-MSH are indicative of structural differences between the peptides, while titration curves suggest structural similarities between each peptide and its Toac-labeled species, in aqueous solution. Though less sensitive than fluorescence, the Toac electron spin resonance (ESR) isotropic hyperfine splitting parameter can also monitor the titration of side-chain residues located relatively far from the probe.
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11
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Pogozheva ID, Chai BX, Lomize AL, Fong TM, Weinberg DH, Nargund RP, Mulholland MW, Gantz I, Mosberg HI. Interactions of human melanocortin 4 receptor with nonpeptide and peptide agonists. Biochemistry 2005; 44:11329-41. [PMID: 16114870 PMCID: PMC2532597 DOI: 10.1021/bi0501840] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Specific interactions of human melanocortin-4 receptor (hMC4R) with its nonpeptide and peptide agonists were studied using alanine-scanning mutagenesis. The binding affinities and potencies of two synthetic, small-molecule agonists (THIQ, MB243) were strongly affected by substitutions in transmembrane alpha-helices (TM) 2, 3, 6, and 7 (residues Glu(100), Asp(122), Asp(126), Phe(261), His(264), Leu(265), and Leu(288)). In addition, a I129A mutation primarily affected the binding and potency of THIQ, while F262A, W258A, Y268A mutations impaired interactions with MB243. By contrast, binding affinity and potency of the linear peptide agonist NDP-MSH were substantially reduced only in D126A and H264A mutants. Three-dimensional models of receptor-ligand complexes with their agonists were generated by distance-geometry using the experimental, homology-based, and other structural constraints, including interhelical H-bonds and two disulfide bridges (Cys(40)-Cys(279), Cys(271)-Cys(277)) of hMC4R. In the models, all pharmacophore elements of small-molecule agonists are spatially overlapped with the corresponding key residues (His(6), d-Phe(7), Arg(8), and Trp(9)) of the linear peptide: their charged amine groups interact with acidic residues from TM2 and TM3, similar to His(6) and Arg(6) of NDP-MSH; their substituted piperidines mimic Trp(9) of the peptide and interact with TM5 and TM6, while the d-Phe aromatic rings of all three agonists contact with Leu(133), Trp(258), and Phe(261) residues.
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MESH Headings
- Amino Acid Sequence
- Binding Sites
- Cyclic AMP/pharmacology
- Humans
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Peptides/pharmacology
- Piperazines/pharmacology
- Piperidines/pharmacology
- Protein Structure, Secondary
- Receptor, Melanocortin, Type 4/agonists
- Receptor, Melanocortin, Type 4/chemistry
- Receptor, Melanocortin, Type 4/drug effects
- Receptor, Melanocortin, Type 4/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/drug effects
- Recombinant Proteins/metabolism
- Rhodopsin/chemistry
- Sequence Alignment
- Sequence Homology, Amino Acid
- Transfection
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Affiliation(s)
- Irina D Pogozheva
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109, USA
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12
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Catania A, Grieco P, Randazzo A, Novellino E, Gatti S, Rossi C, Colombo G, Lipton JM. Three-dimensional structure of the alpha-MSH-derived candidacidal peptide [Ac-CKPV]2. ACTA ACUST UNITED AC 2005; 66:19-26. [PMID: 15946192 DOI: 10.1111/j.1399-3011.2005.00265.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Previous research has shown that the immunomodulatory peptide alpha-melanocyte-stimulating hormone (alpha-MSH) and its carboxy-terminal tripeptide KPV (Lys-Pro-Val alpha-MSH11-13) have antimicrobial influences. By inserting a Cys-Cys linker between two units of KPV, we designed the dimer [Ac-CKPV]2 that showed excellent candidacidal effects in pilot tests and was the subject of further investigations. [Ac-CKPV]2 was active against azole-resistant Candida spp. Therefore, the molecule appeared a promising candidate for therapy of fungal infections and was the subject of a structural study. 1H-NMR and restrained mechanic and dynamic calculations suggest that the peptide adopts an extended backbone structure with a beta-turn-like structure. These results open a pathway to development of additional novel compounds that have candidacidal effects potentially useful against clinical infections.
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Affiliation(s)
- A Catania
- Division of Internal Medicine, Ospedale Maggiore di Milano IRCCS, 20122 Milano, Italy.
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13
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Mutulis F, Mutule I, Liepinsh E, Yahorau A, Lapinsh M, Kopantshuk S, Veiksina S, Rinken A, Wikberg JES. N-alkylated dipeptide amides and related structures as imitations of the melanocortins' active core. Peptides 2005; 26:1997-2016. [PMID: 15985308 DOI: 10.1016/j.peptides.2004.11.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2004] [Accepted: 11/20/2004] [Indexed: 11/22/2022]
Abstract
Thirty-three low molecular mass structures combining both peptide and peptoid features were prepared and tested on human melanocortin receptors MC1,3-5R. Most of them displayed low micromolar activity with preference for diamines, guanidino and 2-naphthyl derivatives compared to monoacetylated, amino and 3-indolyl counterparts. Some contained L- or D-histidine residues, but the change did not influence affinity. QSAR modelling yielded excellent models for the MC3-5 receptors explaining R2Y=0.89-0.91 and predicting Q2=0.77-0.80 of the affinity variations. One compound displayed MC1R selectivity (13-fold and more). An NMR study of showed that it exists as a mixture of four rotamers at its tertiary amide bonds. Comparisons with earlier data for melanocortin core tetrapeptide analogues indicate that the novel peptide-peptoids interact with the melanocortin receptors in a different way.
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Affiliation(s)
- Felikss Mutulis
- Department of Pharmaceutical Biosciences, Division of Pharmacology, Uppsala University, Box 591, Biomedicum, SE-751 24 Uppsala, Sweden
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14
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Holder JR, Haskell-Luevano C. Melanocortin ligands: 30 years of structure-activity relationship (SAR) studies. Med Res Rev 2004; 24:325-56. [PMID: 14994367 DOI: 10.1002/med.10064] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The challenge of peptide and peptidomimetic research is the development of methods and techniques to improve the biological properties of native peptides and to convert peptide ligands into non-peptide compounds. Improved biological properties of peptides includes enhancement of stability, potency, and receptor selectivity, for both in vivo and in vitro applications. The design of a ligand with specific activity and desired biological properties is a complex task, and, to accomplish this objective, knowledge about putative interactions between a ligand and the corresponding receptor will be valuable. This includes interactions for both the binding and signal transduction processes. Structure-activity relationship (SAR) studies involve systematic modification of a lead peptide and are designed to provide insight into potential interactions involved in the formation of the ligand-receptor complex. It is desirable to have knowledge about both favorable and unfavorable processes that may occur in putative ligand-receptor interactions that result in either receptor stimulation or inhibition. Herein, we discuss various SAR studies that have involved melanocortin peptides over three decades and the information these studies have provided to the melanocortin field.
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Affiliation(s)
- Jerry Ryan Holder
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, USA
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15
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Ying J, Kövér KE, Gu X, Han G, Trivedi DB, Kavarana MJ, Hruby VJ. Solution structures of cyclic melanocortin agonists and antagonists by NMR. Biopolymers 2004; 71:696-716. [PMID: 14991679 DOI: 10.1002/bip.10596] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The melanocortin receptors are involved in many physiological functions, including pigmentation, sexual function, feeding behavior, and energy homeostasis, making them potential targets for drugs to treat obesity, sexual dysfunction, etc. Understanding the conformational basis of the receptor-ligand interactions is crucial to the design of potent and selective ligands for these receptors. The solution structures of the cyclic melanocortin agonists, partial agonist, and antagonists MTII, VJH085, SHU9119, MK5, and MK9 were determined by two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy at pH 4.5 and 25 degrees C in water (90% H(2)O/10% D(2)O). The overall backbone structures of these cyclic alpha-melanocyte-stimulating hormone (alpha-MSH) analogues around the message sequence (His(6)-D-Phe(7)/D-Nal(2')(7)-Arg(8)-Trp(9)) were similar and reasonably well defined. beta-Turns spanning His(6) and D-Phe(7)/D-Nal(2')(7) were identified in all analogues, and an amphiphilic molecular surface was obtained for the message sequence residues in most structures within the NMR ensembles. The beta-turn, which most closely resembles a type II beta-turn, leads to stacking between the aromatic rings of His(6) and D-Phe(7) in MTII and VJH085. However, no aromatic stacking between His(6) and D-Nal(2')(7) was found in structures of the D-Nal(2')(7)-containing analogues. The difference in the side-chain dispositions of His(6) and D-Nal(2')(7) may be responsible for the reduced potency or antagonist activity of the D-Nal(2')(7)-containing analogues. In addition, our results suggest that the side-chain orientations may also modulate the receptor selectivity. The information found in this study will be useful for the further design of ligands for melanocortin receptors.
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Affiliation(s)
- Jinfa Ying
- Department of Chemistry, University of Arizona, Tucson, AZ 85721, USA
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16
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Desai P, Prachand M, Coutinho E, Saran A, Bodi J, Süli-Vargha H. Activity and conformation of a cyclic heptapeptide possessing the message sequence His-Phe-Arg-Trp of alpha-melanotropin. Int J Biol Macromol 2002; 30:187-95. [PMID: 12063121 DOI: 10.1016/s0141-8130(02)00019-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Alpha-melanotropin (alpha-MSH, i.e. alpha-melanocyte stimulating hormone), tridecapeptide (Ac-Ser(1)-Tyr-Ser-Met-G1u(5)-His-Phe-Arg-Trp-Gly(10)-Lys-Pro-Val(13)-NH(2)), has been extensively studied to understand structure-activity relationships. The core sequence (His-Phe-Arg-Trp) is conserved in several species and is considered as the primary active site or "message sequence". Attempts have been made to design conformationally constrained cyclic analogs containing the message sequence to improve the activity. We had earlier reported that the cyclic analog--cyclo[Gly-His-D-Phe-Arg-Trp-Gly], a 18 membered ring system with two fused beta-turn structure, was less active than the corresponding linear peptide. It was suggested that ring size could be an important parameter in the activity of cyclic melanotropic analogs. To investigate the effect of ring size on biological activity, a cyclic heptapeptide, cyclo[Nle(1)-Gly-His-D-Phe-Arg(5)-Trp-Gly(7)], with 21 member ring system was synthesized. This peptide has three orders of magnitude higher biological activity than the cyclic hexapeptide. The conformational study of this cyclic heptapeptide in DMSO-d(6) by NMR and molecular dynamics simulations reveals a structure with two fused beta-turns running across the residues D-Phe(4)-Gly(7) (Type I) and Gly(7)-His(3) (Type II). These findings confirm that stabilization of beta-turns and a relatively larger ring size are essential determinants of activity for cyclic alpha-MSH analogs.
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Affiliation(s)
- Prashant Desai
- Department of Pharmaceutical Chemistry, Bombay College of Pharmacy, Kalina, Mumbai 400098, India
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17
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Prabhu NV, Dalosto SD, Sharp KA, Wright WW, Vanderkooi JM. Optical Spectra of Fe(II) Cytochrome c Interpreted Using Molecular Dynamics Simulations and Quantum Mechanical Calculations. J Phys Chem B 2002. [DOI: 10.1021/jp014208y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ninad V. Prabhu
- Johnson Research Foundation, Department of Biochemistry & Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Sergio D. Dalosto
- Johnson Research Foundation, Department of Biochemistry & Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Kim A. Sharp
- Johnson Research Foundation, Department of Biochemistry & Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - W. W. Wright
- Johnson Research Foundation, Department of Biochemistry & Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Jane M. Vanderkooi
- Johnson Research Foundation, Department of Biochemistry & Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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18
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Prabhu NV, Siddiqui SA, McMurray JS, Pettitt BM. Structural basis for the activity of pp60(c-src) protein tyrosine kinase inhibitors. Biopolymers 2001; 59:167-79. [PMID: 11391566 DOI: 10.1002/1097-0282(200109)59:3<167::aid-bip1016>3.0.co;2-l] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Conformational searches on three closely related pp60(c-src) protein tyrosine kinase inhibitors of varying potencies were performed to determine a structural basis for their activity. The first was a linear peptide (PDNEYAFFQf), the second its 10-membered cyclic analogue, and the third a cyclic analogue with a para carboxyphenylalanine in place of one the F residues. A common backbone conformation with an antiparallel beta-sheet-like geometry capped by similar beta-turns was found for all three peptides, which may be a binding conformation and gives a candidate pharmacophore for further testing. The interaction between some polar side chains and between some of the aromatic rings may be important for maintaining the correct conformation. The differences in potencies of these inhibitors may be attributed to certain thermodynamic and chemical reasons.
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Affiliation(s)
- N V Prabhu
- Department of Chemistry, University of Houston, Houston, TX 77204-5641, USA
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19
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Ito AS, Souza ES, dos Reis Barbosa S, Nakaie CR. Fluorescence study of conformational properties of melanotropins labeled with aminobenzoic acid. Biophys J 2001; 81:1180-9. [PMID: 11463659 PMCID: PMC1301587 DOI: 10.1016/s0006-3495(01)75775-x] [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: 11/28/2022] Open
Abstract
The native hormone alpha-melanocyte-stimulating hormone (alpha-MSH) and its more potent analog [Nle(4),D-Phe(7)]alpha-MSH (NDP-alpha MSH), labeled at the amino terminal with the fluorescent aminobenzoic acid (Abz) isomers, were examined by fluorescence methods. We observed energy transfer between the tryptophan(9) residue acting as donor and Abz as acceptor, the transfer being more pronounced to the ortho-form of the acceptor. Within the hypothesis that different peptide conformations coexist in equilibrium during the fluorescence decay, we supposed that the intensity decay was modulated by an acceptor-donor distance distribution function f(r). From the time-resolved fluorescence experimental data, we recovered the distance distribution between Abz and Trp(9), using the CONTIN program, within the framework of the Förster resonance energy transfer model. The methodology proved to be useful to provide quantitative information about conformational dynamics of melanotropins and its dependency on the solvent. In aqueous medium, alpha-MSH has a broad Abz-Trp(9) distance distribution, reflecting the structural flexibility of the peptide. Three different distance populations could be identified in the labeled analog NDP-alpha MSH in water, indicating distinct conformational states for the synthetic peptide, compared with the native hormone. Measurements in trifluoroethanol resulted in the recovery of two Abz-Trp(9) distance populations, both for the native and the analog hormones, reflecting the decrease, induced by the solvent, of the conformational states available to the peptides.
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Affiliation(s)
- A S Ito
- Faculdade de Filosofia Ciências e Letras de Ribeirão Preto da Universidade de São Paulo, São Paulo, Brasil.
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20
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Chavatte P, Yous S, Lesieur D, Hénichart JP. Conformational analysis of tripeptide Ac-Lys-Pro-Val-NH2, COOH-terminal sequence of alpha-MSH. J Pharm Pharmacol 2001; 53:949-53. [PMID: 11480545 DOI: 10.1211/0022357011776360] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Alpha-melanocyte stimulating hormone (alpha-MSH) is an endogenous linear tridecapeptide which interacts with the melanocortin receptors (MC1-R to MC5-R) to mediate its biological effects. Antipyretic and anti-inflammatory activities of alpha-MSH are due to the COOH-terminal peptide sequence, Lys-Pro-Val (alpha-MSH[11-13]). This tripeptide might be useful as a therapeutic agent in the control of fever and inflammatory reactions. With this aim, a theoretical conformational study of the tripeptide has been carried out using molecular dynamics. The obtained conformational space has been classified into families according to the letter-code convention to partition the phi-psi map. The lowest energy conformations of each family were used as templates to design six models of conformationally constrained nonpeptide analogues.
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Affiliation(s)
- P Chavatte
- Institut de Chimie Pharmaceutique Albert Lespagnol, Lille, France
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21
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Prusis P, Muceniece R, Mutule I, Mutulis F, Wikberg JE. Design of new small cyclic melanocortin receptor-binding peptides using molecular modelling: Role of the His residue in the melanocortin peptide core. Eur J Med Chem 2001; 36:137-46. [PMID: 11311745 DOI: 10.1016/s0223-5234(00)01200-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The conserved core of melanocyte stimulating hormones (MSH), His-Phe-Arg-Trp, was probed by comparing a cyclic pentapeptide containing His-DPhe-Arg-Trp, with three structurally similar cyclic peptides, that lacked the His residue. All three peptides bound to the MC(1), MC(3), MC(4) and MC(5) receptors with similar affinities. Molecular modelling indicated that the 3D structure of the DPhe-Arg-Trp of all three peptides were closely similar. The data indicate that the His residue of the small rigid cyclic MSH core peptides does not participate in binding with the melanocortin receptors.
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Affiliation(s)
- P Prusis
- Department of Pharmaceutical Pharmacology, Uppsala University, SE-751 24, Uppsala, Sweden
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