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Nuti F, Larregola M, Staśkiewicz A, Retzl B, Tomašević N, Macchia L, Street ME, Jewgiński M, Lequin O, Latajka R, Rovero P, Gruber CW, Chorev M, Papini AM. Design, synthesis, conformational analysis, and biological activity of Cα 1-to-Cα 6 1,4- and 4,1-disubstituted 1 H-[1,2,3]triazol-1-yl-bridged oxytocin analogues. J Enzyme Inhib Med Chem 2023; 38:2254019. [PMID: 37735942 PMCID: PMC10519257 DOI: 10.1080/14756366.2023.2254019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 08/26/2023] [Indexed: 09/23/2023] Open
Abstract
Oxytocin (OT) is a neurohypophyseal peptide hormone containing a disulphide-bridged pseudocyclic conformation. The biomedical use of OT peptides is limited amongst others by disadvantageous pharmacokinetic parameters. To increase the stability of OT by replacing the disulphide bridge with the stable and more rigid [1,2,3]triazol-1-yl moiety, we employed the Cu2+-catalysed side chain-to-side chain azide-alkyne 1,3-cycloaddition. Here we report the design, synthesis, conformational analysis, and in vitro pharmacological activity of a homologous series of Cα1-to-Cα6 side chain-to-side chain [1,2,3]triazol-1-yl-containing OT analogues differing in the length of the bridge, location, and orientation of the linking moiety. Exploiting this macrocyclisation approach, it was possible to generate a systematic series of compounds providing interesting insight into the structure-conformation-function relationship of OT. Most analogues were able to adopt similar conformation to endogenous OT in water, namely, a type I β-turn. This approach may in the future generate stabilised pharmacological peptide tools to advance understanding of OT physiology.
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Affiliation(s)
- Francesca Nuti
- Interdepartmental Research Unit of Peptide and Protein Chemistry and Biology, Department of Chemistry “Ugo Schiff”, University of Florence, Sesto Fiorentino, Florence, Italy
| | - Maud Larregola
- CNRS, BioCIS, CY Cergy Paris Université, Cergy Pontoise and Paris Saclay Université, Orsay, France
| | - Agnieszka Staśkiewicz
- Interdepartmental Research Unit of Peptide and Protein Chemistry and Biology, Department of Chemistry “Ugo Schiff”, University of Florence, Sesto Fiorentino, Florence, Italy
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wrocław University of Science and Technology, Wrocław, Poland
| | - Bernhard Retzl
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Nataša Tomašević
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Lorenzo Macchia
- Interdepartmental Research Unit of Peptide and Protein Chemistry and Biology, Department of Chemistry “Ugo Schiff”, University of Florence, Sesto Fiorentino, Florence, Italy
| | - Maria E. Street
- Dipartimento di Medicina e Chirurgia, Università di Parma e Clinica Pediatrica, AOU di Parma, Parma, Italy
| | - Michał Jewgiński
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wrocław University of Science and Technology, Wrocław, Poland
| | - Olivier Lequin
- Laboratoire des Biomolécules, Sorbonne Université, Ecole Normale Supérieure, PSL University, CNRS, Paris, France
| | - Rafal Latajka
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wrocław University of Science and Technology, Wrocław, Poland
| | - Paolo Rovero
- Interdepartmental Research Unit of Peptide and Protein Chemistry and Biology, Department of NeuroFarBa, University of Florence, Sesto Fiorentino, Florence, Italy
| | - Christian W. Gruber
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Michael Chorev
- Laboratory for Translational Research, Department of Medicine, Division of Hematology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Anna Maria Papini
- Interdepartmental Research Unit of Peptide and Protein Chemistry and Biology, Department of Chemistry “Ugo Schiff”, University of Florence, Sesto Fiorentino, Florence, Italy
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2
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Miao J, Descoteaux ML, Lin YS. Structure prediction of cyclic peptides by molecular dynamics + machine learning. Chem Sci 2021; 12:14927-14936. [PMID: 34820109 PMCID: PMC8597836 DOI: 10.1039/d1sc05562c] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 10/14/2021] [Indexed: 12/27/2022] Open
Abstract
Recent computational methods have made strides in discovering well-structured cyclic peptides that preferentially populate a single conformation. However, many successful cyclic-peptide therapeutics adopt multiple conformations in solution. In fact, the chameleonic properties of some cyclic peptides are likely responsible for their high cell membrane permeability. Thus, we require the ability to predict complete structural ensembles for cyclic peptides, including the majority of cyclic peptides that have broad structural ensembles, to significantly improve our ability to rationally design cyclic-peptide therapeutics. Here, we introduce the idea of using molecular dynamics simulation results to train machine learning models to enable efficient structure prediction for cyclic peptides. Using molecular dynamics simulation results for several hundred cyclic pentapeptides as the training datasets, we developed machine-learning models that can provide molecular dynamics simulation-quality predictions of structural ensembles for all the hundreds of thousands of sequences in the entire sequence space. The prediction for each individual cyclic peptide can be made using less than 1 second of computation time. Even for the most challenging classes of poorly structured cyclic peptides with broad conformational ensembles, our predictions were similar to those one would normally obtain only after running multiple days of explicit-solvent molecular dynamics simulations. The resulting method, termed StrEAMM (Structural Ensembles Achieved by Molecular Dynamics and Machine Learning), is the first technique capable of efficiently predicting complete structural ensembles of cyclic peptides without relying on additional molecular dynamics simulations, constituting a seven-order-of-magnitude improvement in speed while retaining the same accuracy as explicit-solvent simulations.
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Affiliation(s)
- Jiayuan Miao
- Department of Chemistry, Tufts University Medford Massachusetts 02155 USA
| | - Marc L Descoteaux
- 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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3
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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: 44] [Impact Index Per Article: 14.7] [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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4
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Kecel-Gunduz S, Budama-Kilinc Y, Cakir-Koc R, Zorlu T, Bicak B, Kokcu Y, E Ozel A, Akyuz S. In Silico design of AVP (4-5) peptide and synthesis, characterization and in vitro activity of chitosan nanoparticles. ACTA ACUST UNITED AC 2020; 28:139-157. [PMID: 31942695 DOI: 10.1007/s40199-019-00325-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 12/23/2019] [Indexed: 02/03/2023]
Abstract
BACKGROUND Arginine-vasopressin (AVP) is a neuropeptide and provides learning and memory modulation. The AVP (4-5) dipeptide corresponds to the N-terminal fragment of the major vasopressin metabolite AVP (4-9), has a neuroprotective effect and used in the treatment of Alzheimer's and Parkinson's disease. METHODS The main objective of the present study is to evaluate the molecular mechanism of AVP (4-5) dipeptide and to develop and synthesize chitosan nanoparticle formulation using modified version of ionic gelation method, to increase drug effectiveness. For peptide loaded chitosan nanoparticles, the synthesized experiment medium was simulated for the first time by molecular dynamics method and used to determine the stability of the peptide, and the binding mechanism to protein (HSP70) was also investigated by molecular docking calculations. A potential pharmacologically features of the peptide was also characterized by ADME (Absorption, Distribution, Metabolism and Excretion) analysis. The characterization, in vitro release study, encapsulation efficiency and loading capacity of the peptide loaded chitosan nanoparticles (CS NPs) were performed by Dynamic Light Scattering (DLS), UV-vis absorption (UV), Scanning Electron Microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy techniques. Additionally, in vitro cytotoxicity of the peptide on human neuroblastoma cells (SH-SY5Y) was examined with XTT assay and the statistical analysis was evaluated. RESULTS The results showed that; hydrodynamic size, zeta potential and polydispersity index (PdI) of the peptide-loaded CS NPs were 167.6 nm, +13.2 mV, and 0.211, respectively. In vitro release study of the peptide-loaded CS NPs showed that 17.23% of the AVP (4-5)-NH2 peptide was released in the first day, while 61.13% of AVP (4-5)-NH2 peptide was released in the end of the 10th day. The encapsulation efficiency and loading capacity were 99% and 10%, respectively. According to the obtained results from XTT assay, toxicity on SHSY-5Y cells in the concentration from 0.01 μg/μL to 30 μg/μL were evaluated and no toxicity was observed. Also, neuroprotective effect was showed against H2O2 treatment. CONCLUSION The experimental medium of peptide-loaded chitosan nanoparticles was created for the first time with in silico system and the stability of the peptide in this medium was carried out by molecular dynamics studies. The binding sites of the peptide with the HSP70 protein were determined by molecular docking analysis. The size and morphology of the prepared NPs capable of crossing the blood-brain barrier (BBB) were monitored using DLS and SEM analyses, and the encapsulation efficiency and loading capacity were successfully performed with UV Analysis. In vitro release studies and in vitro cytotoxicity analysis on SHSY-5Y cell lines of the peptide were conducted for the first time. Grapical abstract.
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Affiliation(s)
- Serda Kecel-Gunduz
- Physics Department, Faculty of Science, Istanbul University, Vezneciler, 34134, Istanbul, Turkey.
| | - Yasemin Budama-Kilinc
- Department of Bioengineering, Faculty of Chemical and Metallurgical Engineering, Yildiz Technical University, 34220, Istanbul, Turkey
| | - Rabia Cakir-Koc
- Department of Bioengineering, Faculty of Chemical and Metallurgical Engineering, Yildiz Technical University, 34220, Istanbul, Turkey
| | - Tolga Zorlu
- Graduate School of Natural and Applied Science, Yildiz Technical University, 34220, Istanbul, Turkey.,Department of Physical Chemistry and EMaS, Universitat Rovira i Virgili, 43007, Tarragona, Spain
| | - Bilge Bicak
- Physics Department, Faculty of Science, Istanbul University, Vezneciler, 34134, Istanbul, Turkey.,Institute of Graduate Studies in Sciences, Istanbul University, 34452, Istanbul, Turkey
| | - Yagmur Kokcu
- Institute of Graduate Studies in Sciences, Istanbul University, 34452, Istanbul, Turkey
| | - Aysen E Ozel
- Physics Department, Faculty of Science, Istanbul University, Vezneciler, 34134, Istanbul, Turkey
| | - Sevim Akyuz
- Physics Department, Science and Letters Faculty, Istanbul Kultur University, Atakoy Campus, Bakirkoy, 34156, Istanbul, Turkey
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5
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Lubecka EA, Sikorska E, Sobolewski D, Prahl A, Slaninová J, Ciarkowski J. Potent antidiuretic agonists, deamino-vasopressin and desmopressin, and their inverso analogs: NMR structure and interactions with micellar and liposomic models of cell membrane. Biopolymers 2016; 106:245-59. [PMID: 26916937 DOI: 10.1002/bip.22825] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 02/11/2016] [Accepted: 02/13/2016] [Indexed: 11/08/2022]
Abstract
Deamination of vasopressin (AVP) enhances its antidiuretic activity. Moreover, introduction of D-Arg8 instead of its L enantiomer in deamino-vasopressin (dAVP) results in an extremely potent and selective antidiuretic agonist - desmopressin (dDAVP). In this study we describe the synthesis, pharmacological properties and structures of these two potent antidiuretic agonists, and their inverso analogs. The structures of the peptides are studied in micellar and liposomic models of cell membrane using CD spectroscopy. Additionally, three-dimensional structures in mixed anionic-zwitterionic micelles are obtained using NMR spectroscopy supported by molecular dynamics simulations. Our conformational studies have shown that desmopressin in a membrane mimicking environment adopts one of the characteristic for vasopressin-like peptides β-turn - in position 3,4. Furthermore, dDAVP shows the tendency to create a β-turn in the Cys6-Gly9 C-tail, considered to be important for the antidiuretic activity, and also some tendency to adopt a 5,6 β-turn. In desmopressin, in contrast to the native vasopressin, deamino-vasopressin and [D-Arg8]-vasopressin (DAVP), the Arg8 side chain, crucial for the pressor and antidiuretic activities, is very well exposed for interaction with the receptor, whereas Gly9, crucial for the pressor and uterotonic activities, is situated together with the C-terminal amide group very close to the tocin ring. The arrangements of the Gln4 and Asn5 side chains, being crucial for OT activity, also differ in desmopressin as compared to those of AVP, dAVP and DAVP. These differences in arrangement of the important for activities side chains are likely to explain extremely potent and selective antidiuretic activities of desmopressin. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 245-259, 2016.
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Affiliation(s)
- Emilia A Lubecka
- Faculty of Chemistry, University of Gdańsk, Gdańsk, 80-308, Poland
| | - Emilia Sikorska
- Faculty of Chemistry, University of Gdańsk, Gdańsk, 80-308, Poland
| | | | - Adam Prahl
- Faculty of Chemistry, University of Gdańsk, Gdańsk, 80-308, Poland
| | - Jiřina Slaninová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10 Prague, Czech Republic
| | - Jerzy Ciarkowski
- Faculty of Chemistry, University of Gdańsk, Gdańsk, 80-308, Poland
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6
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Lubecka EA, Sikorska E, Sobolewski D, Prahl A, Slaninová J, Ciarkowski J. Arginine-, D-arginine-vasopressin, and their inverso analogues in micellar and liposomic models of cell membrane: CD, NMR, and molecular dynamics studies. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2015; 44:727-43. [PMID: 26290060 PMCID: PMC4628624 DOI: 10.1007/s00249-015-1071-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/22/2015] [Accepted: 08/03/2015] [Indexed: 01/21/2023]
Abstract
We describe the synthesis, pharmacological properties, and structures of antidiuretic agonists, arginine vasopressin (AVP) and [d-Arg8]-vasopressin (DAVP), and their inverso analogues. The structures of the peptides are studied based on micellar and liposomic models of cell membranes using CD spectroscopy. Additionally, three-dimensional structures in mixed anionic–zwitterionic micelles are obtained using NMR spectroscopy and molecular dynamics simulations. NMR data have shown that AVP and DAVP tend to adopt typical of vasopressin-like peptides β-turns: in the 2–5 and 3–6 fragments. The inverso-analogues also adopt β-turns in the 3–6 fragments. For this reason, their inactivity seems to be due to the difference in side chains orientations of Tyr2, Phe3, and Arg8, important for interactions with the receptors. Again, the potent antidiuretic activity of DAVP can be explained by CD data suggesting differences in mutual arrangement of the aromatic side chains of Tyr2 and Phe3 in this peptide in liposomes rather than of native AVP. In the presence of liposomes, the smallest conformational changes of the peptides are noticed with DPPC and the largest with DPPG liposomes. This suggests that electrostatic interactions are crucial for the peptide–membrane interactions. We obtained similar, probably active, conformations of the antidiuretic agonists in the mixed DPC/SDS micelles (5:1) and in the mixed DPPC/DPPG (7:3) liposomes. Thus it can be speculated that the anionic–zwitterionic liposomes as well as the anionic–zwitterionic micelles, mimicking the eukaryotic cell membrane environment, partially restrict conformational freedom of the peptides and probably induce conformations resembling those of biologically relevant ones.
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Affiliation(s)
- Emilia A Lubecka
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308, Gdańsk, Poland.
| | - Emilia Sikorska
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308, Gdańsk, Poland
| | - Dariusz Sobolewski
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308, Gdańsk, Poland
| | - Adam Prahl
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308, Gdańsk, Poland
| | - Jiřina Slaninová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10, Prague, Czech Republic
| | - Jerzy Ciarkowski
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308, Gdańsk, Poland
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Kulkarni AK, Ojha RP. Conformations of a model cyclic hexapeptide, CYIQNC: (1)H-NMR and molecular dynamics studies. J Biomol Struct Dyn 2014; 33:1850-65. [PMID: 25375824 DOI: 10.1080/07391102.2014.975283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Solution conformation of the cyclic hexapeptide sequence, [cyclo-S-Cys-Tyr-Ile-Gln-Asn-Cys-S] (CYIQNC) - a disulfide-linked fragment of a neurohypophyseal peptide hormone oxytocin (OT) - has been investigated by high-field one-dimensional (1D) and two-dimensional (2D) NMR spectroscopic methods and compared with the results obtained from computer simulation studies. (1)H-NMR results based on temperature dependence of amide proton chemical shifts and nuclear Overhauser effect indicate that peptide in solution populates different conformations, characterized by two fused β-turns. The segment Ile(3)-Gln(4)-Asn(5)-Cys(6) yields a preferred type-III β-turn at residues 4, 5 (HB, 3HN → 6CO), while the segment Cys(6), Cys(1)-Tyr(2)-Ile(3) exhibits inherently weaker, flexible β-turn either of type I/II'/III/half-turn at residues 1, 2 (HB, 6HN → 3CO). The computer simulation studies using a mixed protocol of distance geometry-simulated annealing followed by constrained minimization, restrained molecular dynamics, and energy minimization showed the possibility of existence of additional conformations with the hydrogen bonds, (a) 5HN → 3CO and (b) 2HN → 6CO. These results, therefore, indicate that the additional conformations obtained from both NMR and simulation studies can also be possible to the peptide. These additional conformations might have very small population in the solution and did not show their signatures in these conditions. These findings will be helpful in designing more analogs with modifications in the cyclic moiety of OT.
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Affiliation(s)
- Ashok Kumar Kulkarni
- a Department of Physiology , MediCiti Institute of Medical Sciences , Ghanpur, Medchal Mandal, R. R. Dist., Hyderabad 501401 , India
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8
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Haensele E, Banting L, Whitley DC, Clark T. Conformation and dynamics of 8-Arg-vasopressin in solution. J Mol Model 2014; 20:2485. [DOI: 10.1007/s00894-014-2485-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 10/06/2014] [Indexed: 01/12/2023]
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Hill TA, Shepherd NE, Diness F, Fairlie DP. Constraining cyclic peptides to mimic protein structure motifs. Angew Chem Int Ed Engl 2014; 53:13020-41. [PMID: 25287434 DOI: 10.1002/anie.201401058] [Citation(s) in RCA: 306] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 04/02/2013] [Indexed: 12/18/2022]
Abstract
Many proteins exert their biological activities through small exposed surface regions called epitopes that are folded peptides of well-defined three-dimensional structures. Short synthetic peptide sequences corresponding to these bioactive protein surfaces do not form thermodynamically stable protein-like structures in water. However, short peptides can be induced to fold into protein-like bioactive conformations (strands, helices, turns) by cyclization, in conjunction with the use of other molecular constraints, that helps to fine-tune three-dimensional structure. Such constrained cyclic peptides can have protein-like biological activities and potencies, enabling their uses as biological probes and leads to therapeutics, diagnostics and vaccines. This Review highlights examples of cyclic peptides that mimic three-dimensional structures of strand, turn or helical segments of peptides and proteins, and identifies some additional restraints incorporated into natural product cyclic peptides and synthetic macrocyclic peptidomimetics that refine peptide structure and confer biological properties.
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Affiliation(s)
- Timothy A Hill
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072 (Australia)
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10
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Hill TA, Shepherd NE, Diness F, Fairlie DP. Fixierung cyclischer Peptide: Mimetika von Proteinstrukturmotiven. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201401058] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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11
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Yedvabny E, Nerenberg PS, So C, Head-Gordon T. Disordered structural ensembles of vasopressin and oxytocin and their mutants. J Phys Chem B 2014; 119:896-905. [PMID: 25231121 DOI: 10.1021/jp505902m] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Vasopressin and oxytocin are intrinsically disordered cyclic nonapeptides belonging to a family of neurohypophysial hormones. Although unique in their functions, these peptides differ only by two residues and both feature a tocin ring formed by the disulfide bridge between first and sixth cysteine residues. This sequence and structural similarity are experimentally linked to oxytocin agonism at vasopressin receptors and vasopressin antagonism at oxytocin receptors. Yet single- or double-residue mutations in both peptides have been shown to have drastic impacts on their activities at either receptor, and possibly the ability to bind to their neurophysin carrier protein. In this study we perform molecular dynamics simulations of the unbound native and mutant sequences of the oxytocin and vasopressin hormones to characterize their structural ensembles. We classify the subpopulations of these structural ensembles on the basis of the distributions of radius of gyration and secondary structure and hydrogen-bonding features of the canonical tocin ring and disordered tail region. We then relate the structural changes observed in the unbound form of the different hormone sequences to experimental information about peptide receptor binding, and more indirectly, carrier protein binding affinity, receptor activity, and protease degradation. This study supports the hypothesis that the structural characteristics of the unbound form of an IDP can be used to predict structural or functional preferences of its functional bound form.
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Affiliation(s)
- Eugene Yedvabny
- Department of Chemistry, ‡Department of Bioengineering, and §Department of Chemical and Biomolecular Engineering, University of California , Berkeley, California 94720-3220, United States
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12
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Pliska V, Folkers G, Spiwok V. Thermodynamics of the interaction between oxytocin and its myometrial receptor in sheep: a stepwise binding mechanism. Biochem Pharmacol 2014; 91:119-27. [PMID: 25010721 DOI: 10.1016/j.bcp.2014.06.025] [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: 04/12/2014] [Revised: 06/27/2014] [Accepted: 06/30/2014] [Indexed: 11/16/2022]
Abstract
Entropy (ΔS), enthalpy (ΔH) and heat capacity (ΔCp) changes attending the oxytocin interaction with its two binding sites on myometrial cell membranes in sheep were derived from the temperature dependence of Kd values. The high affinity oxytocin site (Kd on the order of 10(-9)mol l(-1), 25 °C), ascribed to the oxytocin receptor (OXTR), is entropy-driven in the temperature range 0-37 °C. Enthalpy component prevails as a driving force in the binding to the low affinity site (Kd ≈ 10(-7)) within the higher temperature range. ΔCp values in both cases do not differ significantly from zero but become highly relevant in the presence of a GTP analog (10(-4)M GTP-γS). Under these conditions, ΔCp in the low site interaction becomes negative and ΔS is shifted toward negative values (enthalpy drift); ΔCp of the high affinity site rises to a high positive value and the interaction is even more strongly entropy driven. Atosiban, a competitive antagonist of oxytocin at OXTR displays a single significant binding site on myometrial cells (Kd about 10(-7)mol l(-1)). Thermodynamic profiles of atosiban and the low affinity oxytocin site show conspicuous similarities, indicating that the inhibitor is bound to the low affinity site, and not, with a lower affinity, to the putative receptor protein. It is suggested that the interaction of oxytocin with its responding system on myometrial membranes follows in two distinct steps that are likely to be associated with several independent binding domains in the GPCR receptor.
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Affiliation(s)
- Vladimir Pliska
- Collegium Helveticum, Swiss Federal Institute of Technology (ETH-Zürich) and University of Zurich, Schmelzbergstrasse 25, CH-8092 Zürich, Switzerland; Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH-Zürich), Campus Hönggerberg, CH-8093 Zürich, Switzerland.
| | - Gerd Folkers
- Collegium Helveticum, Swiss Federal Institute of Technology (ETH-Zürich) and University of Zurich, Schmelzbergstrasse 25, CH-8092 Zürich, Switzerland; Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH-Zürich), Campus Hönggerberg, CH-8093 Zürich, Switzerland
| | - Vojtěch Spiwok
- Department of Biochemistry and Microbiology, Institute of Chemical Technology (VŠCHT-Prague), Technická 5, CZ-166 28 Praha 6, Czech Republic
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13
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Lubecka EA, Sikorska E, Marcinkowska A, Ciarkowski J. Conformational studies of neurohypophyseal hormones analogues with glycoconjugates by NMR spectroscopy. J Pept Sci 2014; 20:406-14. [DOI: 10.1002/psc.2628] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 02/18/2014] [Accepted: 02/21/2014] [Indexed: 11/05/2022]
Affiliation(s)
- Emilia A. Lubecka
- Faculty of Chemistry; University of Gdańsk; Wita Stwosza 63 80-952 Gdańsk Poland
| | - Emilia Sikorska
- Faculty of Chemistry; University of Gdańsk; Wita Stwosza 63 80-952 Gdańsk Poland
| | - Alina Marcinkowska
- Faculty of Chemistry; University of Gdańsk; Wita Stwosza 63 80-952 Gdańsk Poland
| | - Jerzy Ciarkowski
- Faculty of Chemistry; University of Gdańsk; Wita Stwosza 63 80-952 Gdańsk Poland
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Lubecka EA, Ciarkowski J, Prahl A, Sikorska E. Highly Potent Antidiuretic Antagonists: Conformational Studies of Vasopressin Analogues Modified with 1-Naphthylalanine Enantiomers at Position 2. Chem Biol Drug Des 2012; 79:1033-42. [DOI: 10.1111/j.1747-0285.2012.01358.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Kaltenböck A, Hibert M, Langer T. Putative Dynamics of Vasopressin in its V1a Receptor Binding Site. ACTA ACUST UNITED AC 2011. [DOI: 10.3109/10606820308251] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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16
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Libster D, Aserin A, Garti N. Interactions of biomacromolecules with reverse hexagonal liquid crystals: Drug delivery and crystallization applications. J Colloid Interface Sci 2011; 356:375-86. [DOI: 10.1016/j.jcis.2011.01.047] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Revised: 01/13/2011] [Accepted: 01/14/2011] [Indexed: 11/26/2022]
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17
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Garibotto FM, Garro AD, Rodríguez AM, Raimondi M, Zacchino SA, Perczel A, Somlai C, Penke B, Enriz RD. Penetratin analogues acting as antifungal agents. Eur J Med Chem 2011; 46:370-7. [DOI: 10.1016/j.ejmech.2010.10.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 10/21/2010] [Accepted: 10/26/2010] [Indexed: 11/16/2022]
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18
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Olivella MS, Rodríguez AM, Zacchino SA, Somlai C, Penke B, Farkas V, Perczel A, Enriz RD. New antifungal peptides. Synthesis, bioassays and initial structure prediction by CD spectroscopy. Bioorg Med Chem Lett 2010; 20:4808-11. [DOI: 10.1016/j.bmcl.2010.06.105] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 06/14/2010] [Accepted: 06/21/2010] [Indexed: 11/25/2022]
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19
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Lubecka E, Kwiatkowska A, Ciarkowski J, Sikorska E. NMR studies of new arginine vasopressin analogs modified with alpha-2-indanylglycine enantiomers at position 2 bound to sodium dodecyl sulfate micelles. Biophys Chem 2010; 151:139-48. [PMID: 20598431 DOI: 10.1016/j.bpc.2010.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 06/08/2010] [Accepted: 06/08/2010] [Indexed: 11/17/2022]
Abstract
In this paper, we use NMR spectroscopy and molecular modeling to examine four new vasopressin analogs modified with alpha-2-indanylglycine (Igl) at position 2, [L-Igl(2)]AVP (I), [D-Igl(2)]AVP (II), [Mpa(1),L-Igl(2)]AVP (III) and [Mpa(1),D-Igl(2)]AVP (IV), embedded in a sodium dodecyl sulfate (SDS) micelle. All the analogs display antiuterotonic activity. In addition, the analogs with D-Igl reveal antipressor properties. Each analog exhibits the tendency to adopt beta-turns at positions 2, 3 and/or 3, 4, which is characteristic of oxytocin-like peptides. Mutual arrangement of aromatic residues at positions 2 and 3 has been found to be crucial for binding antagonists with the OT and V(1a) receptors. The orientation of the Gln(4) side chain seems to be important for the V(1a) receptor affinity. In each of the peptides studied, the Gln(4) side chain is folded back over the ring moiety. However, it lies on the opposite face of the tocin moiety in analogs with L and D enantiomers of Igl.
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20
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Xu X, Yu W, Huang Z, Lin Z. Comprehensive Density Functional Theory Study on the Mechanism of Activation of the Nonapeptide Hormone Oxytocin by Metal Ions. J Phys Chem B 2010; 114:1417-23. [DOI: 10.1021/jp907436p] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xuee Xu
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China, and Department of Physics, University of Science and Technology of China, Hefei 230026, China
| | - Wenbo Yu
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China, and Department of Physics, University of Science and Technology of China, Hefei 230026, China
| | - Zhijian Huang
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China, and Department of Physics, University of Science and Technology of China, Hefei 230026, China
| | - Zijing Lin
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China, and Department of Physics, University of Science and Technology of China, Hefei 230026, China
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21
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Garibotto FM, Garro AD, Masman MF, Rodríguez AM, Luiten PG, Raimondi M, Zacchino SA, Somlai C, Penke B, Enriz RD. New small-size peptides possessing antifungal activity. Bioorg Med Chem 2010; 18:158-67. [DOI: 10.1016/j.bmc.2009.11.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 11/03/2009] [Accepted: 11/04/2009] [Indexed: 11/24/2022]
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22
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Libster D, Aserin A, Yariv D, Shoham G, Garti N. Concentration- and Temperature-Induced Effects of Incorporated Desmopressin on the Properties of Reverse Hexagonal Mesophase. J Phys Chem B 2009; 113:6336-46. [DOI: 10.1021/jp810309d] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Dima Libster
- Casali Institute of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel, Department of Inorganic Chemistry and the Laboratory for Structural Chemistry and Biology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Abraham Aserin
- Casali Institute of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel, Department of Inorganic Chemistry and the Laboratory for Structural Chemistry and Biology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Doron Yariv
- Casali Institute of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel, Department of Inorganic Chemistry and the Laboratory for Structural Chemistry and Biology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Gil Shoham
- Casali Institute of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel, Department of Inorganic Chemistry and the Laboratory for Structural Chemistry and Biology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Nissim Garti
- Casali Institute of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel, Department of Inorganic Chemistry and the Laboratory for Structural Chemistry and Biology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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23
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Ciszewska M, Kwasiborska M, Nowakowski M, Oleszczuk M, Wójcik J, Chung NN, Schiller PW, Izdebski J. N-(ureidoethyl)amides of cyclic enkephalin analogs. J Pept Sci 2009; 15:312-8. [DOI: 10.1002/psc.1118] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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24
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Sikorska née Trzepałka E, Ślusarz R, Lammek B. Conformational studies of highly potent 1-aminocyclohexane-1-carboxylic acid substituted V2 vasopressin agonists. ACTA ACUST UNITED AC 2008. [DOI: 10.1111/j.1747-0285.2006.00336.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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25
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Masman MF, Somlai C, Garibotto FM, Rodríguez AM, de la Iglesia A, Zacchino SA, Penke B, Enriz RD. Structure-antifungal activity relationship of His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2 and analogues. Bioorg Med Chem 2008; 16:4347-58. [PMID: 18346897 DOI: 10.1016/j.bmc.2008.02.072] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Revised: 02/20/2008] [Accepted: 02/22/2008] [Indexed: 11/28/2022]
Abstract
The synthesis, in vitro evaluation and conformational study of His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH(2) and analogues acting as antifungal agents are reported. Among them, His-Phe-Lys-Trp-Gly-Arg-Phe-Val-NH(2) exhibited a moderate but significant antifungal activity against Cryptococcus neoformans, Candida albicans and Candida tropicalis. A theoretical study allows us to propose a biologically relevant conformation for these octapeptides acting as antifungal agents. In addition, these theoretical calculations allow us to determine the minimal structural requirements to produce the antifungal response and can provide a guide for the design of compounds with this biological activity.
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Affiliation(s)
- Marcelo F Masman
- Departamento de Química, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco 915, 5700 San Luis, Argentina
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26
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Möller C, Marí F. A vasopressin/oxytocin-related conopeptide with gamma-carboxyglutamate at position 8. Biochem J 2007; 404:413-9. [PMID: 17331075 PMCID: PMC1896288 DOI: 10.1042/bj20061480] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Vasopressins and oxytocins are homologous, ubiquitous and multifunctional peptides present in animals. Conopressins are vasopressin/oxytocin-related peptides that have been found in the venom of cone snails, a genus of marine predatory molluscs that envenom their prey with a complex mixture of neuroactive peptides. In the present paper, we report the purification and characterization of a unique conopressin isolated from the venom of Conus villepinii, a vermivorous cone snail species from the western Atlantic Ocean. This novel peptide, designated gamma-conopressin-vil, has the sequence CLIQDCPgammaG* (gamma is gamma-carboxyglutamate and * is C-terminal amidation). The unique feature of this vasopressin/oxytocin-like peptide is that the eighth residue is gamma-carboxyglutamate instead of a neutral or basic residue; therefore it could not be directly classified into either the vasopressin or the oxytocin peptide families. Nano-NMR spectroscopy of the peptide isolated directly from the cone snails revealed that the native gamma-conopressin-vil undergoes structural changes in the presence of calcium. This suggests that the peptide binds calcium, and the calcium-binding process is mediated by the gamma-carboxyglutamate residue. However, the negatively charged residues in the sequence of gamma-conopressin-vil may mediate calcium binding by a novel mechanism not observed in other peptides of this family.
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Affiliation(s)
- Carolina Möller
- Department of Chemistry and Biochemistry, and Center of Excellence in Biomedical and Marine Biotechnology, Florida Atlantic University, Boca Raton, FL 33431, U.S.A
| | - Frank Marí
- Department of Chemistry and Biochemistry, and Center of Excellence in Biomedical and Marine Biotechnology, Florida Atlantic University, Boca Raton, FL 33431, U.S.A
- To whom correspondence should be addressed (email )
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27
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Witkowska E, Nowakowski M, Oleszczuk M, Filip K, Ciszewska M, Chung NN, Schiller PW, Wójcik J, Izdebski J. Ureido group containing cyclic dermorphin(1–7) analogues: synthesis, biology and conformation. J Pept Sci 2007; 13:519-28. [PMID: 17605130 DOI: 10.1002/psc.877] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Six cyclic peptides related to dermorphin(1-7) have been synthesized. The synthesis of linear peptides containing diamino acid residues in positions 2 and 4 was carried out on a 4-methylbenzhydrylamine resin, and cyclization was achieved by treatment with bis-(4-nitrophenyl)carbonate to form a urea unit. The peptides were tested in the guinea-pig ileum (GPI) and mouse vas deferens (MVD) assays. Diverse opioid agonist activities were observed, depending on the size of the ring. The results were compared with those obtained earlier for 1-4 dermorphin analogues. The conformations of all six dermorphin analogues were studied. The conformational space of the peptides was examined using the electrostatically driven Monte Carlo method. On the basis of NMR data, an ensemble of conformations was obtained for each peptide. The opioid activity profiles of the compounds are discussed in the light of the structural data.
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Affiliation(s)
- Ewa Witkowska
- Peptide Laboratory, Department of Chemistry, Warsaw University, Pasteura 1, 02-093 Warsaw, Poland
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28
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Sikorska E, Rodziewicz-MotowidŁo S. Conformational studies of vasopressin and mesotocin using NMR spectroscopy and molecular modelling methods. Part I: studies in water. J Pept Sci 2007; 14:76-84. [DOI: 10.1002/psc.918] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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29
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Masman MF, Rodríguez AM, Svetaz L, Zacchino SA, Somlai C, Csizmadia IG, Penke B, Enriz RD. Synthesis and conformational analysis of His-Phe-Arg-Trp-NH2 and analogues with antifungal properties. Bioorg Med Chem 2006; 14:7604-14. [PMID: 16926096 DOI: 10.1016/j.bmc.2006.07.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Accepted: 07/01/2006] [Indexed: 11/30/2022]
Abstract
The synthesis, in vitro evaluation, and conformational study of His-Phe-Arg-Trp-NH2 and related derivatives acting as antifungal agents are reported. Among them, His-Phe-Arg-Trp-NH2 and His-Tyr-Arg-Trp-NH2 exhibited antifungal activity against Cryptococcus neoformans. Antifungal activity of these compounds appears to be closely related to the alpha-MSH effect. A conformational and electronic study allows us to propose a biologically relevant conformation for these tetrapeptides acting as antifungal agents. In addition, these theoretical calculations permit us to determine the minimal structural requirements to produce the antifungal response and may provide a guide for the design of compounds with this biological activity.
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Affiliation(s)
- Marcelo F Masman
- Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco 915, 5700 San Luis, Argentina
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30
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Podstawka E, Sikorska E, Proniewicz LM, Lammek B. Raman and surface-enhanced Raman spectroscopy investigation of vasopressin analogues containing 1-aminocyclohexane-1-carboxylic acid residue. Biopolymers 2006; 83:193-203. [PMID: 16741975 DOI: 10.1002/bip.20545] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In this work, Raman spectroscopy (RS) was employed to characterize molecular structures of [Arg8]vasopressin (AVP) and its [Acc2,D-Arg8]AVP, [Acc3]AVP, and [Cpa1, Acc3]AVP analogues. The RS band assignments have been proposed. To determine the mechanism of adsorption of the above-mentioned compounds adsorbed on a colloidal silver surface, surface-enhanced Raman spectra (SERS) were measured. The SERS spectra were used to determine relative proximity of the adsorbed functional groups of [corrected] investigated peptides and their orientation on the silver surface. The AVP and [Acc3]AVP SERS spectra (Acc: 1-aminocyclohexane-1-carboxylic acid) show that the L-tyrosine (Tyr) lies far from the metal surface, whereas the [Cpa1,Acc3]AVP spectrum (Cpa: 1-mercaptocyclohexaneacetic acid) provides evidence that Tyr interacts with the silver surface. These results suggest that [corrected] the binding of the Tyr-ionized phenolic group might be responsible for the selectivity of the analogues. We show that the aromatic ring of L-phenylalanine (Phe) of AVP and [Acc2,D-Arg8]AVP interacts with the silver surface. The strength of this interaction is considerably weaker for [Acc2,D-Arg8]AVP than for AVP. This might be due either to a longer distance between the Phe ring and the silver surface, or to the almost perpendicular orientation of the Phe ring towards the surface. The carbonyl group of the L-glutamine [corrected] (Gln) or L-asparagine [corrected](Asn) of AVP, [Acc2,D-Arg8]AVP, and [Acc3]AVP is strongly bound to the silver surface. We have also found that all peptides adsorb on the silver surface via sulfur atoms of the disulfide bridge, adopting a "GGG" conformation, except [Cpa1,Acc3]AVP, which accepts a "TGG" geometry.
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Affiliation(s)
- Edyta Podstawka
- Laser Raman Laboratory, Regional Laboratory of Physicochemical Analysis and Structural Research, Jagiellonian University, Ingardena 3 Str., 30-060 Kraków, Poland
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31
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Sikorska E, Slusarz MJ, Slusarz R, Kowalczyk W, Lammek B. Investigation ofcis/trans ratios of peptide bonds in AVP analogues containingN-methylphenylalanine enantiomers. J Pept Sci 2005; 12:13-24. [PMID: 15959924 DOI: 10.1002/psc.684] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The solution conformation of vasopressin analogues, modified at positions 2 and 3 with N-methylphenylalanine or its enantiomer, [D-MePhe2,MePhe3]AVP and [MePhe2,D-MePhe3]AVP, were studied by 2D NMR spectroscopy in H2O/D2O and theoretical calculations (EDMC/ANALYZE). In the case of [MePhe2,D-MePhe3]AVP, the synthesis afforded two products, A and B, which had identical molecular ions and similar retention times on HPLC. This finding was explained by racemization of Cys1, which gave an additional analogue, [D-Cys1,MePhe2,D-MePhe3]AVP (B). The possibility is not excluded of racemization of Cys1 in the remaining analogues of this series. However, only in the case of [MePhe2,D-MePhe3]AVP was this process so distinct that two strong peaks in the HPLC chromatogram were observed. The NMR spectra of all the analogues showed several distinct sets of residual proton resonances. This suggests that the peptides adopt more than two groups of conformations in H2O/D2O. This fact is due to cis/trans isomerization. Two more populated isomers arise from the cis/trans isomerization across the 2-3 peptide bond in [D-MePhe2,MePhe3]AVP and [MePhe2,D-MePhe3]AVP (A) and across the 1-2 peptide bond in [D-Cys1,MePhe2,D-MePhe3]AVP (B).
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Affiliation(s)
- Emilia Sikorska
- Faculty of Chemistry, University of Gdańsk, Sobieskiego 18, 80-952 Gdańsk, Poland.
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32
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Filip K, Oleszczuk M, Wójcik J, Chung NN, Schiller PW, Pawlak D, Zieleniak A, Parcińska A, Witkowska E, Izdebski J. Cyclic enkephalin and dermorphin analogues containing a carbonyl bridge. J Pept Sci 2004; 11:347-52. [PMID: 15635652 DOI: 10.1002/psc.613] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Four cyclic enkephalin analogues and four cyclic dermorphin analogues have been synthesized. Cyclization of linear peptides containing basic amino acid residues of various side chain length in position 2 and 5 (enkephalin analogues) or 2 and 4 (dermorphin analogues) was achieved by treatment with bis-(4-nitrophenyl) carbonate to form a urea unit. The peptides were tested in the guinea-pig ileum (GPI) and mouse vas deferens (MVD) assays. Diverse activity was observed, depending on the size of the ring and the location of the urea unit. The conformation of two dermorphin analogues has been studied: one of high activity (IC(50) = 4.15 nM in the GPI assay) and a second of low activity (IC(50) = 6700 nM in the GPI assay). The conformational space of these peptides was examined using the EDMC method. Using data from the NMR spectra, each peptide was described as an ensemble of conformers. Biological activity was discussed in light of the structural data.
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Affiliation(s)
- Katarzyna Filip
- Peptide Laboratory, Department of Chemistry, Warsaw University, Pasteura 1, Warsaw, 02-093 Poland
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33
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Filip K, Oleszczuk M, Pawlak D, Wojcik J, Chung NN, Schillerc PW, Izdebski J. Potent side-chain to side-chain cyclized dermorphin analogues containing a carbonyl bridge. J Pept Sci 2003; 9:649-57. [PMID: 14620130 DOI: 10.1002/psc.510] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A new family of cyclic opioid peptide analogues related to the 1-4 sequence of dermorphin/deltorphin (Tyr-D-Aaa2-Phe-Aaa4-NH2) has been synthesized. The synthesis of the linear precursor peptides was accomplished by the solid-phase method and ring formation was achieved via a ureido group incorporating the side chain amino functions of D-Aaa2 (D-Lys, D-Orn) and Aaa4 (Lys, Orn, Dab, Dap). The peptides were tested in the guinea-pig ileum (GPI) and mouse vas deferens (MVD) assays. Most showed very high agonist potency in the GPI assay. The peptide containing D-Lys in position 2 and Dab in position 4 was 210 times more active than enkephalin, and that containing Orn and Dab, respectively, was 150 times more active than enkephalin. The latter peptide was also very active in the MVD assay, and showed an IC50 MVD/GPI ratio of 0.816. NMR spectra of selected peptides were recorded, and structural parameters were determined. The conformational space of the peptides was examined using the electrostatically driven Monte Carlo method. With the help of the NMR spectra each peptide was described as an ensemble of conformations. The conformations have been interpreted with regard to the opioid activities, and comparisons have been made with a model proposed earlier for enkephalin analogues.
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MESH Headings
- Analgesics, Opioid/chemical synthesis
- Analgesics, Opioid/chemistry
- Analgesics, Opioid/pharmacology
- Animals
- Guinea Pigs
- In Vitro Techniques
- Magnetic Resonance Spectroscopy
- Mice
- Muscle Contraction/drug effects
- Muscle, Smooth/drug effects
- Muscle, Smooth/metabolism
- Oligopeptides/chemical synthesis
- Oligopeptides/chemistry
- Oligopeptides/pharmacology
- Opioid Peptides
- Peptides, Cyclic/chemical synthesis
- Peptides, Cyclic/chemistry
- Peptides, Cyclic/pharmacology
- Protein Conformation
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, mu/agonists
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Affiliation(s)
- Katarzyna Filip
- Laboratory of Peptides, Department of Chemistry, Warsaw University, Pasteura 1, Warsaw, 02-093 Poland
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34
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Liepiņa I, Czaplewski C, Janmey P, Liwo A. Molecular dynamics study of a gelsolin-derived peptide binding to a lipid bilayer containing phosphatidylinositol 4,5-bisphosphate. Biopolymers 2003; 71:49-70. [PMID: 12712500 DOI: 10.1002/bip.10375] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Gelsolin is an actin-severing protein whose action is initiated by Ca(2+) and inhibited by binding to phosphorylated inositol lipid or phosphoinositides. The regions of gelsolin responsible for phosphoinositide binding are comprised of residues 150-169 (G150-169) and 135-142 (G135-142). The corresponding peptides possess similar binding potency as native gelsolin. Their common feature is the presence of arginine and lysine residues that can bind to negatively charged phosphate groups of phosphoinositides. In this work the binding of the G150-169 peptide to a phosphatidylinositol 4,5-bisphosphate (PIP2) cluster in a lipid membrane model was investigated by molecular dynamics calculations (MD) with the AMBER 4.1 force field, taking into account explicit solvent molecules. Initially the structure of G150-169 was simulated by using the electrostatically driven Monte Carlo (EDMC) and MD methods, and the resulting structure agreed within 3.7 A backbone-atom root mean square deviation with the corresponding experimentally derived structure (PDB code: 1SOL). Using this model for the peptide, a subsequent MD simulation of G150-169 in a periodic box containing a model of dimyristoyl-phosphatidylcholine (DMPC) lipids with a cluster of four PIP2 molecules was carried out. During the simulation G150-169 interacted strongly with PIP2 molecules, initially by formation of salt bridges between its N-terminal basic groups and the phosphate groups of PIP2, followed by formation of hydrophobic bonds between the hydrophobic side chains of the peptide and the fatty acid tail of the lipid. As a result of the formation of hydrophobic bonds, the PIP2 molecules were pulled out from the lipid bilayer. This mode of binding differs from those of other PIP2-binding protein motifs such as PH domains that interact solely with the hydrophilic head group of PIP2. These results suggest that dissociation of gelsolin from actin by PIP2 lipids may involve entering of the PIP2 molecules to the gelsolin-actin interface, thereby weakening the interactions between these proteins.
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Affiliation(s)
- Inta Liepiņa
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga, LV1006, Latvia
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35
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Rodziewicz-Motowidło S, Zhukov I, Kasprzykowski F, Grzonka Z, Ciarkowski J, Wójcik J. Conformational solution studies of (Sar7)desamino- and (MeAla7)desamino-vasopressin analogues using NMR spectroscopy. J Pept Sci 2002; 8:347-64. [PMID: 12148784 DOI: 10.1002/psc.394] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Solution structures of two analogues of vasopressin with an amino acid sequence of c[Mpa1-Tyr2-Phe3-Gln4-Asn5-Cys6]-Xaa7-Arg8-Gly9-NH2 (Xaa = Sar [I] or MeAla [II]) were established using ROE and the 3J(HNH alpha) couplings. Each of the peptides was found to exist in two stable isomers, pertaining to the cis or trans status of the Cys6-Xaa7 peptide bond, thus giving rise to four study objects. Two methods for studies of the conformational properties of the structures were compared. In the first, the algorithm consisted of three steps: (i) An Electrostatically Driven Monte-Carlo (EDMC) search for low-energy conformations. (ii) Simulations of the NOESY spectra and the vicinal couplings for these conformations. (iii) Determination of the statistical weights of the conformations with the ANALYZE package, so as to meet the best fit of the averaged NOE intensities and couplings to the experimental data. In the second method, the distance constraints and the torsion angles were used as the usual constraints in the Distance Geometry and Simulated Annealing algorithms. The flexibility of the pressin ring and the C-terminus was characterized by a large number of families of conformations. The presence of the beta-turn at position 4,5 was confirmed for all low energy structures found. The use of the EDMC method for the elaboration of the NMR data for small flexible peptides yielded an adequate description of their conformational diversity and is the method of choice for the analysis of their solution structures.
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Malicka J, Groth M, Czaplewski C, Wiczk W, Liwo A. Conformational studies of cyclic enkephalin analogues with L- or D-proline in position 3. Biopolymers 2002; 63:217-31. [PMID: 11807749 DOI: 10.1002/bip.10068] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The conformation of a series of cyclic enkephalin analogues of a general formula X(1)-cyclo[Y(2)-Z(3)-Nal(4)-Leu(5)] (Nal: beta-(2-naphthyl)alanine), where X = Tyr, Phe, or Phe(NO(2)), Y = D-Dab or L-Dab (Dab: 2,4-diaminobutyric acid), and Z = D-Pro or L-Pro, was studied by means of NMR spectroscopy and theoretical conformational analysis with the Empirical Conformational Energy Program for Peptides and Proteins force field plus solvation. The NMR measurements were performed in dimethyl sulfoxide solution. The nuclear Overhauser effect intensities and coupling constants were used to compute the statistical weights of the conformations of the ensemble generated in global conformational searches. The purpose of this study was to determine whether introducing the D- or L-proline residue in position 3 can produce peptides with both rigid backbone and significant separation of the pharmacophore groups in position 1 and 4 (as required for high affinity for the mu-type opioid receptors). It was found that the analogues with D-Dab in position 2 and D-Pro in position 3 possess a stable type II' beta-turn at positions 3 and 4, which rigidifies the cyclic backbone; this finding was confirmed by independent measurements of the temperature coefficients of the amide protons, which indicated very significant screening of the Leu(5) amide proton from the solvent. However, these analogues were found to possess a short interchromophore distance. The analogues containing both Dab and Pro in the L-configuration are characterized by a larger interchromophore distance; however, they do not possess a stable beta-turn and have therefore a higher conformational flexibility. The modifications proposed in this work are therefore not likely to lead to enkephalin analogues with a high affinity for the mu-receptors.
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Scheraga HA, Pillardy J, Liwo A, Lee J, Czaplewski C, Ripoll DR, Wedemeyer WJ, Arnautova YA. Evolution of physics-based methodology for exploring the conformational energy landscape of proteins. J Comput Chem 2002; 23:28-34. [PMID: 11913387 DOI: 10.1002/jcc.1154] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The evolution of our physics-based computational methods for determining protein conformation without the introduction of secondary-structure predictions, homology modeling, threading, or fragment coupling is described. Initial use of a hard-sphere potential captured much of the structural properties of polypeptide chains, and subsequent more refined force fields, together with efficient methods of global optimization provide indications that progress is being made toward an understanding of the interresidue interactions that underlie protein folding.
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Affiliation(s)
- Harold A Scheraga
- Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853-1301, USA.
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39
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Groth M, Malicka J, Rodziewicz- Motowidło S, Czaplewski C, Klaudel L, Wiczk W, Liwo A. Determination of conformational equilibrium of peptides in solution by NMR spectroscopy and theoretical conformational analysis: application to the calibration of mean-field solvation models. Biopolymers 2001; 60:79-95. [PMID: 11455544 DOI: 10.1002/1097-0282(2001)60:2<79::aid-bip1006>3.0.co;2-l] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Peptides occur in solution as ensembles of conformations rather than in a fixed conformation. The existing energy functions are usually inadequate to predict the conformational equilibrium in solution, because of failure to account properly for solvation, if the solvent is not considered explicitly (which is usually prohibitively expensive). NMR data are therefore widely incorporated into theoretical conformational analysis. Because of conformational flexibility, restrained molecular dynamics (with restraints derived from NMR data), which is usually applied to determine protein conformation is of limited use in the case of peptides. Instead, (a) the restraints are averaged within predefined time windows during molecular dynamics (MD) simulations (time averaging), (b) multiple-copy MD simulations are carried out and the restraints are averaged over the copies (ensemble averaging), or (c) a representative ensemble of sterically feasible conformations is generated and the weights of the conformations are then fitted so that the computed average observables match the experimental data (weight fitting). All these approaches are briefly discussed in this article. If an adequate force field is used, conformations with large statistical weights obtained from the weight-fitting procedure should also have low energies, which can be implemented in force field calibration. Such a procedure is particularly attractive regarding the parameterization of the solvation energy in nonaqueous solvents, e.g., dimethyl sulfoxide, for which thermodynamic solvation data are scarce. A method for calibration of solvation parameters in dimethyl sulfoxide, which is based on this principle was recently proposed by C. Baysal and H. Meirovitch (Journal of the American Chemical Society, 1998, Vol. 120, pp. 800--812), in which the energy gap between the conformations compatible with NMR data and the alternative conformations is maximized. In this work we propose an alternative method based on the principle that the best-fitting statistical weights of conformations should match the Boltzmann weights computed with the force field applied. Preliminary results obtained using three test peptides of varying conformational mobility: H-Ser(1)-Pro(2)-Lys(3)-Leu(4)-OH, Ac-Tyr(1)-D-Phe(2)-Ser(3)-Pro(4)-Lys(5)-Leu(6)-NH(2), and cyclo(Tyr(1)-D-Phe(2)-Ser(3)-Pro(4)-Lys(5)-Leu(6)) are presented.
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Affiliation(s)
- M Groth
- Faculty of Chemistry University of Gdańsk Sobieskiego 18 80-952 Gdańsk Poland
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40
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Malicka J, Groth M, Karolczak J, Czaplewski C, Liwo A, Wiczk W. Influence of solvents and leucine configuration at position 5 on tryptophan fluorescence in cyclic enkephalin analogues. Biopolymers 2001; 58:447-57. [PMID: 11180057 DOI: 10.1002/1097-0282(20010405)58:4<447::aid-bip1020>3.0.co;2-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The fluorescence decay of tryptophan is a sensitive indicator of its local environment within a peptide or protein. In this study we carried out fluorescence measurements of the tryptophan residue of cyclic enkephalin analogues of a general formula X-c[D-Dab(2)-Gly(3)-Trp(4)-Y(5)] where X = Cbz or H and Y = D- or L-Leu, in four solvents [water, methanol, acetonitrile, and dimethyl sulfoxide (DMSO)]. An analysis of the tryptophan fluorescence decays using a discrete-exponential model indicates that tryptophan fluorescence decay can be described by a double exponential function in all solvents studied. Lifetime distribution analysis yields a bimodal distribution in protic solvents (water and methanol), whereas an asymmetric, unimodal distribution in an aprotic solvent (DMSO) and uni- or bimodal distributions in acetonitrile solution, depending on leucine configuration. The data are interpreted in terms of the rotamer model, in which the modality and the relative proportions of the lifetime components are related to the population distribution of tryptophan chi(1) rotamers about the C(alpha)--C(beta) bond. The chirality of the Leu(5) residue and solvent properties affect the local environment of the tryptophan residue and therefore influence the distribution of side-chain rotamers. These results are consistent with the results of theoretical conformational calculations.
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Affiliation(s)
- J Malicka
- University of Gdańsk, Faculty of Chemistry, Sobieskiego 18, 80-952 Gdańsk, Poland
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41
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Pawlak D, Oleszczuk M, Wójcik J, Pachulska M, Chung NN, Schiller PW, Izdebski J. Highly potent side-chain to side-chain cyclized enkephalin analogues containing a carbonyl bridge: synthesis, biology and conformation. J Pept Sci 2001; 7:128-40. [PMID: 11297348 DOI: 10.1002/psc.303] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Six novel cyclic enkephalin analogues have been synthesized. Cyclization of the linear peptides containing basic amino acid residues in position 2 and 5 was achieved by treatment with bis(4-nitrophenyl)carbonate. It was found that some of the compounds exibit unusually high mu-opioid activity in the guinea pig ileum (GPI) assay. The 18-membered analogue cyclo(N(epsilon),N(beta)-carbonyl-D-Lys2,Dap5)-enkephalinamide turned out to be one of the most potent mu-agonists reported so far. NMR spectra of the peptides were recorded and structural parameters were determined. The conformational space was exhaustively examined for each of them using the electrostatically driven Monte Carlo method. Each peptide was finally described as an ensemble of conformations. A model of the bioactive conformation of this class of opioid peptides was proposed.
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Affiliation(s)
- D Pawlak
- Department of Chemistry, University of Warsaw, Poland
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Rachkov A, Minoura N. Towards molecularly imprinted polymers selective to peptides and proteins. The epitope approach. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1544:255-66. [PMID: 11341934 DOI: 10.1016/s0167-4838(00)00226-0] [Citation(s) in RCA: 286] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In this paper, we describe the epitope approach to molecular imprinting. The applicability of molecular imprinting, a method that allows the preparation of biomimetic compounds (artificial receptors and antibodies), is extended by this approach. Our approach makes it possible to obtain imprinted polymers selective to peptides and proteins whereas, to date, molecular imprinting has been used primarily for the preparation of polymers that selectively bind to relatively low molecular weight substances. The epitope approach is based on using (as a template) a short peptide that represents only part of a larger peptide or protein (as an epitope represents an antigen), which in turn can be recognized by the synthesized polymer. It is demonstrated that although other parts of peptides can influence the process of molecular recognition, the polymers imprinted with a short peptide efficiently recognize both the template and larger peptides (for example, oxytocin) that possess the same C-terminal part of the structure.
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Affiliation(s)
- A Rachkov
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kiev
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Slusarz R, Kaźmierkiewicz R, Lammek B. Theoretical conformational analysis of six arginine vasopressin analogs with the L-naphthylalanine in position 3. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 2000; 56:352-9. [PMID: 11152294 DOI: 10.1034/j.1399-3011.2000.00743.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Introduction of the naphthylalanine residue into either position 3 of arginine vasopressin (AVP), or its analogs results in peptides with interesting pharmacological properties. The single substituted analog of AVP with L-2-Nal in position 3 causes moderate antiduretic activity, whereas [Mpa1, (L-1-Nal)3, (D-Arg)8] VP and [Mpa1, (L-2-Nal)3, (D-Arg)8] VP are potent and selective V2 agonists. Moreover [(L-2-Nal)3, (D-Arg)8] VP is among the most potent and selective antagonists of V1a receptors. In this study we carried out conformational calculations on [(L-1-Nal)3] AVP, [(L-2-Nal)3] AVP, [(L-1-Nal)3, (D-Arg)8] VP, [(L-2-Nal)3, (D-Arg)8] VP, [Mpa1, (L-1-Nal)3, (D-Arg)8] VP, [Mpa1, (L-2-Nal)3, (D-Arg)8] VP, using the ECEPP/3 force field with and without including hydration to simulate aqueous and nonpolar environments. It was found that in all six compound studied, the low-energy conformations have common geometry and relative energies. Therefore, the modifications of the Phe in position 3 influence the binding to the receptor by changing the size of the third residue, rather than by changing the conformational space. The lowest-energy conformations in the presence and absence of water had beta-turns at residues Phe3-Gln4 and Gln4-Asn5 and Gln4-Asn5, respectively. The conformation at the Gln4-Asn5 turn was most similar to the crystal structure of the pressinoic acid (the cyclic moiety of vasopressin).
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Affiliation(s)
- R Slusarz
- Department of Chemistry, University of Gdańsk, Poland
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Ananthanarayanan VS, Belciug MP, Zhorov BS. Interaction of oxytocin with Ca2+: II. Proton magnetic resonance and molecular modeling studies of conformations of the hormone and its Ca2+ complex. Biopolymers 2000; 40:445-64. [PMID: 9062068 DOI: 10.1002/(sici)1097-0282(1996)40:5%3c445::aid-bip3%3e3.0.co;2-w] [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: 02/03/2023]
Abstract
Drastic changes in the CD and fluorescence spectra of oxytocin [cyclo(Cys1-Tyr2-Ile3-Gln4-Asn5-Cys6)-Pro7-Leu8-Gly 9-NH2] occur on binding Ca2+ in trifluoroethanol (Ananthanarayanan and Brimble, preceding paper). To further characterize the conformation of the Ca(2+)-bound hormone, we carried out 1H-nmr measurements in deuterated trifluorethanol of oxytocin and its 1:1 Ca2+ complex. The one-dimensional nmr data identified residues involved in Ca2+ binding and the extent of their perturbation on Ca2+ addition. The 3JNH-CH coupling constants and two-dimensional nuclear Overhauser effect (NOE) spectral cross peaks confirmed the helical nature of the Ca2+ complex deduced from CD data. Interproton distances in the free hormone and its Ca2+ complex were estimated from the respective NOE data. Apparent global minimum-energy conformations of free and Ca2+ bound oxytocin were computed using the Monte Carlo with energy minimization protocol, with and without incorporating the NOE-derived distance constraints. Taken together, our results show Ca2+ binding to oxytocin to be a two-step process. The binding of the first Ca2+ brings the otherwise extended tail segment of oxytocin closer to the ring moiety so that it wraps around the cation. This causes the maximal extent of change in all the spectral parameters. The subsequent formation of the 2:1 Ca-oxytocin complex results in the tail detaching itself away from the ring so as to bind the second Ca2+ ion. This leads to further spectral changes in the hormone molecule. The tail segment plays a major role in both steps. These observations may be useful in understanding the structural basis of oxytocin action.
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Wiczk W, Lankiewicz L, Kasprzykowski F, Ołdziej S, Szmaciński H, Lakowicz JR, Grzonka Z. Fluorescence study of neurohypophyseal hormones and their analogues. Distance distributions in a series of arginine-vasopressin analogues. EUROPEAN BIOPHYSICS JOURNAL : EBJ 1997; 26:183-93. [PMID: 9232846 PMCID: PMC6884421 DOI: 10.1007/s002490050070] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Analogues of arginine-vasopressin (AVP) in which substitution of the proline residue in position 7 (by either sarcosine or N-methylalanine) combined with replacement of the cysteine residue in position 1 were the subject of a fluorescence and molecular mechanics study. We obtained two groups of analogues: selective antidiuretic agonists (cysteine or beta-mercaptopropionic acid in position 1) and pressor and uterotonic antagonists (deaminopenicillamine or beta-mercapto-beta, beta-cyclopentamethylenepropionic acid in position 1). Using frequency-domain measurements of fluorescence resonance energy transfer (FRET) we estimated the distance distribution between the phenolic ring of Tyr2 and the disulphide bridge Cys1-Cys6. We also analyzed acrylamide quenching of tyrosyl fluorescence to determine the exposure of the tyrosyl ring to the solvent. Results from fluorescence experiments were compared with those from Monte Carlo simulation (ECEPP/3 force-field).
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Affiliation(s)
- W Wiczk
- Faculty of Chemistry, University of Gdańsk, Poland
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Ananthanarayanan VS, Belciug MP, Zhorov BS. Interaction of oxytocin with Ca2+: II. Proton magnetic resonance and molecular modeling studies of conformations of the hormone and its Ca2+ complex. Biopolymers 1996. [DOI: 10.1002/(sici)1097-0282(1996)40:5<445::aid-bip3>3.0.co;2-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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