1
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Joaquin D, Lee MA, Kastner DW, Singh J, Morrill ST, Damstedt G, Castle SL. Impact of Dehydroamino Acids on the Structure and Stability of Incipient 3 10-Helical Peptides. J Org Chem 2019; 85:1601-1613. [PMID: 31730750 DOI: 10.1021/acs.joc.9b02747] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A comparative study of the impact of small, medium-sized, and bulky α,β-dehydroamino acids (ΔAAs) on the structure and stability of Balaram's incipient 310-helical peptide (1) is reported. Replacement of the N-terminal Aib residue of 1 with a ΔAA afforded peptides 2a-c that maintained the 310-helical shape of 1. In contrast, installation of a ΔAA in place of Aib-3 yielded peptides 3a-c that preferred a β-sheet-like conformation. The impact of the ΔAA on peptide structure was independent of size, with small (ΔAla), medium-sized (Z-ΔAbu), and bulky (ΔVal) ΔAAs exerting similar effects. The proteolytic stabilities of 1 and its analogs were determined by incubation with Pronase. Z-ΔAbu and ΔVal increased the resistance of peptides to proteolysis when incorporated at the 3-position and had negligible impact on stability when placed at the 1-position, whereas ΔAla-containing peptides degraded rapidly regardless of position. Exposure of peptides 2a-c and 3a-c to the reactive thiol cysteamine revealed that ΔAla-containing peptides underwent conjugate addition at room temperature, while Z-ΔAbu- and ΔVal-containing peptides were inert even at elevated temperatures. These results suggest that both bulky and more accessible medium-sized ΔAAs should be valuable tools for bestowing rigidity and proteolytic stability on bioactive peptides.
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Affiliation(s)
- Daniel Joaquin
- Department of Chemistry and Biochemistry , Brigham Young University , Provo , Utah 84602 , United States
| | - Michael A Lee
- Department of Chemistry and Biochemistry , Brigham Young University , Provo , Utah 84602 , United States
| | - David W Kastner
- Department of Chemistry and Biochemistry , Brigham Young University , Provo , Utah 84602 , United States
| | - Jatinder Singh
- Department of Chemistry and Biochemistry , Brigham Young University , Provo , Utah 84602 , United States
| | - Shardon T Morrill
- Department of Chemistry and Biochemistry , Brigham Young University , Provo , Utah 84602 , United States
| | - Gracie Damstedt
- Department of Chemistry and Biochemistry , Brigham Young University , Provo , Utah 84602 , United States
| | - Steven L Castle
- Department of Chemistry and Biochemistry , Brigham Young University , Provo , Utah 84602 , United States
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2
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Jiang J, Ma Z, Castle SL. Bulky α,β-dehydroamino acids: their occurrence in nature, synthesis, and applications. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.06.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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3
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Hayashi R, Miyazaki M, Osada S, Kawasaki H, Fujita I, Hamasaki Y, Kodama H. A formyl peptide substituted with a conformationally constrained phenylalanine residue evokes a selective immune response in human neutrophils. Bioorg Med Chem 2013; 21:668-75. [DOI: 10.1016/j.bmc.2012.11.046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 11/28/2012] [Accepted: 11/28/2012] [Indexed: 10/27/2022]
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4
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Khlebnikov AI, Schepetkin IA, Kirpotina LN, Brive L, Dahlgren C, Jutila MA, Quinn MT. Molecular docking of 2-(benzimidazol-2-ylthio)-N-phenylacetamide-derived small-molecule agonists of human formyl peptide receptor 1. J Mol Model 2011; 18:2831-43. [PMID: 22127612 DOI: 10.1007/s00894-011-1307-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 11/07/2011] [Indexed: 12/25/2022]
Abstract
Human N-formyl peptide receptor 1 (FPR1) is a G protein-coupled receptor (GPCR) involved in host defense and sensing cellular damage. Since structure-based ligand design for many GPCRs, including FPR1, is restricted by the lack of experimental three dimensional structures, homology modeling has been widely used to study GPCR-ligand binding. Indeed, receptor-ligand binding mode predictions can be derived from homology modeling with supporting ligand information. In the present work, we report comparative docking studies of 2-(benzimidazol-2-ylthio)-N-phenylacetamide derived FPR1 agonists, identified here and previously, with several known FPR1 peptide agonists in a FPR1 homology model that is based on the crystal structure of bovine rhodopsin. We found that the binding pocket of the most active molecules shares some common features with high affinity FPR1 peptide agonists, suggesting that they may bind to similar binding sites. Classification tree analysis led to the derivation of a good recognition model based on four amino acid descriptors for distinguishing FPR1 ligands from inactive analogs. Hence, the corresponding residues (Thr199, Arg201, Gly202, and Ala261) can be considered as markers of important areas in the ligand binding site. Concurrently, we identified several unique binding features of benzimidazole derivatives and showed that alkoxy-substituents of the benzimidazole ring are located within a FPR1 hole bounded by Thr199, Thr265, Ile268, and Leu271 or in a groove in the vicinity of Leu198, Arg201, Gly202, and Arg205. The understanding of these molecular features will likely prove beneficial in future design of novel FPR1 agonists based on the benzimidazole scaffold.
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5
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Lucente G, Paradisi MP, Giordano C, Sansone A, Torino D, Spisani S. Chemotactic tripeptides incorporating at position 2 alpha-aminoacid residues with unsaturated side chains. Amino Acids 2007; 35:329-38. [PMID: 18163179 DOI: 10.1007/s00726-007-0621-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2007] [Accepted: 10/09/2007] [Indexed: 11/25/2022]
Abstract
New N-For-Met-Leu-Phe-OMe (fMLF-OMe) analogues incorporating three different gamma-delta-didehydro-alpha-aminoacid residues (namely: Alg = (S)-Allylglycine; Dag = Diallylglycine; Cpg = 1-Aminocyclopent-3-ene-1-carboxylic acid) replacing the native (S)-Leucine have been synthesized and their activity towards human neutrophils has been evaluated in comparison with that shown by the reference tripeptide fMLF-OMe. Chemotaxis, lysozyme release and superoxide anion production have been measured. (1)H NMR titration experiments and NOESY spectrum of the Cpg containing model 10 have been discussed in order to ascertain the preferred solution conformations. A fully extended (C(5)) conformation at position 2 and a folded conformation with two consecutive gamma-turns (C(7) structure) have been proposed for the Dag and Cpg containing tripeptides, respectively.
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Affiliation(s)
- G Lucente
- Dipartimento di Studi Farmaceutici, Università degli Studi di Roma La Sapienza, Rome, Italy.
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6
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Cavicchioni G, Fraulini A, Falzarano S, Spisani S. Structure–activity relationship of for-l-Met l-Leu-l-Phe-OMe analogues in human neutrophils. Bioorg Chem 2006; 34:298-318. [PMID: 16919307 DOI: 10.1016/j.bioorg.2006.07.001] [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] [Received: 03/13/2006] [Revised: 06/29/2006] [Accepted: 07/07/2006] [Indexed: 11/22/2022]
Abstract
Neutrophils constitute the first line of defence against bacterial invasion. They migrate to infected tissues along a concentration gradient of chemoattractant molecules, the most important of which is for-Met-Leu-Phe-OH (fMLP). Different responses arise from formylpeptides binding to different isoforms of the specific receptor. The aim of the studies reported herein was to clarify (i) the role of fMLP-OMe amide bonds in receptor-ligand cross-linking, (ii) the nature of the group occupying the N- and C-terminal positions, (iii) the features peculiar to the Met, Leu, and Phe receptor pockets, and (iv) the features which determine the specific neutrophil response.
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Affiliation(s)
- Giorgio Cavicchioni
- Department of Pharmaceutical Sciences, University of Ferrara, 44100 Ferrara, Italy.
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7
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Selvatici R, Falzarano S, Mollica A, Spisani S. Signal transduction pathways triggered by selective formylpeptide analogues in human neutrophils. Eur J Pharmacol 2006; 534:1-11. [PMID: 16516193 DOI: 10.1016/j.ejphar.2006.01.034] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Revised: 01/03/2006] [Accepted: 01/20/2006] [Indexed: 01/01/2023]
Abstract
Human neutrophils are highly specialised for their primary function, i.e. phagocytosis and destruction of microorganisms. Leukocyte recruitment to sites of inflammation and infection is dependent upon the presence of a gradient of locally produced chemotactic factors. The bacterial peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP) was one of the first of these to be identified and is a highly potent leukocyte chemoattractant. It interacts with its receptor on the neutrophil membrane, activating these cells through a G-protein-coupled pathway. Two functional fMLP receptors have thus far been cloned and characterized, namely FPR (formyl peptide receptor) and FPRL1 (FPR like-1), with high and low affinities for fMLP, respectively. FMLP is known to activate phospholipase C (PLC), PLD, PLA2 and phosphatidylinositol-3-kinase (PI3K), and it also activates tyrosine phosphorylation. The second messengers resulting from the fMLP receptor interaction act on various intracellular kinases, including protein kinase C (PKC) and mitogen-activated protein kinases (MAPKs). The activation of these signal transduction pathways is known to be responsible for various biochemical responses which contribute to physiological defence against bacterial infection and cell disruption. This review will consider the ability of selective analogues (ligands able to discriminate between different biological responses) to activate a single spectrum of signal transduction pathways capable of producing a unique set of cellular responses, hypothesising that a distinctive imprint of signal protein activation may exist. Through more complete understanding of intracellular signaling, new drugs could be developed for the selective inflammatory blockade.
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Affiliation(s)
- Rita Selvatici
- Dipartimento di Medicina Sperimentale e Diagnostica, Sezione Genetica Medica, Via Fossato di Mortara 74, Università degli Studi di Ferrara, 44100 Ferrara, Italy
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8
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Rathore RS. Conformational investigations on analogs of inflammation response inducing chemotactic tripeptide fMLP. Biopolymers 2005; 80:651-64. [PMID: 15648091 DOI: 10.1002/bip.20231] [Citation(s) in RCA: 5] [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
Conformations of three analogs of for-L-Met-L-Leu-L-Phe-OH (fMLP), which initiates inflammatory response by interaction with the formyl peptide receptor (FPR), have been investigated by the application of the X-ray crystallographic technique. The investigated analogs of fMLP peptides are as follows: for-L-Met-1-amino-1-cyclooctane-carbonyl(Ac8c)-L-Phe-OMe; for-L-Met-L-Leu-L-p-iodo-Phe-OH; and for-L-Met-di-n-propylglycyl(Dpg)-L-Phe-OMe. The peptide backbone in and is constrained at position of fMLP by the introduction of Calpha,alpha-disubstituted glycines. In peptide, Phe-OMe is substituted by p-iodo-Phe-OH. Crystal structures reveal an overall folded conformation adopted by and. The former is folded in the type II beta-turn, which is stabilized by an intramolecular 1<--4 (formyl) C==O...H--N (Phe) hydrogen bond, whereas the latter is folded in an open turn without any intramolecular hydrogen bond. On the other hand, peptide has an extended conformation, and two different molecules in a crystallographic asymmetric unit form an antiparallel beta-sheet-like structure. In and, residues Ac8c and Dpg adopt left-handed helical and fully extended (C5) conformations, respectively. The cyclooctane ring in Ac8c acquires a boat-chair conformation. Crystal packing of is characterized by the association of aliphatic-aromatic rings via a C--H...pi interaction. In the crystal of, contrary to the usual observations, peptides are interlinked via networks of head-to-tail hydrogen bond and pi...pi interactions, which are generally observed to be mutually exclusive. The structure-function mechanism of the ligand-receptor interaction is discussed.
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9
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Selvatici R, Falzarano S, Traniello S, Pagani Zecchini G, Spisani S. Formylpeptides trigger selective molecular pathways that are required in the physiological functions of human neutrophils. Cell Signal 2003; 15:377-83. [PMID: 12618212 DOI: 10.1016/s0898-6568(02)00123-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
For-Met-Delta(z)Leu-Phe-OMe ([Delta(z)Leu(2)]) is a conformationally restricted for-Met-Leu-Phe-OMe (fMLP-OMe) analogue able to discriminate between different responses of human neutrophils. In contrast, [Delta(z)Leu(2)] significantly activates the transduction pathways-involving Ca(2+), inositol phosphate, and cyclic AMP (cAMP) enhancement, as is the case with the full agonist fMLP-OMe. Here, we have studied the specific involvement of protein kinase C (PKC) isoforms and mitogen activated protein kinases (MAPKs) in the presence or absence of extracellular Ca(2+), being the cation clearly involved in the activation of neutrophils by fMLP. A strong correlation has been found between PKC isoforms, MAPKs and the selective physiological functions by [Delta(z)Leu(2)]-activated neutrophils. In a calcium-free condition, our data suggest that the failure of PKC beta1 translocation and of p38 MAPK phosphorylation by the analogue refers to its inability to induce chemotaxis, and that the failure by both fMLP-OMe and [Delta(z)Leu(2)] to evoke extracellular response kinase 1 and 2 (ERK1/2) phosphorylation would suggest a reduction in superoxide anion production.
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Affiliation(s)
- Rita Selvatici
- Dipartimento di Medicina Sperimentale e Diagnostica, Sezione Genetica Medica, Via L Borsari 46, Università degli Studi di Ferrara, 44100 Ferrara, Italy
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10
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Ferretti ME, Nalli M, Biondi C, Colamussi ML, Pavan B, Traniello S, Spisani S. Modulation of neutrophil phospholipase C activity and cyclic AMP levels by fMLP-OMe analogues. Cell Signal 2001; 13:233-40. [PMID: 11306240 DOI: 10.1016/s0898-6568(01)00140-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP)-OMe (1) analogues for-Thp-Leu-Ain-OMe (2), for-Thp-Leu-Phe-OMe (3), for-Met-Leu-Ain-OMe (4), for-Met-Delta(z)Leu-Phe-OMe (5), for-Met-Lys-Phe-For-Met-Lys-Phe (6), for-Met-Leu-Pheol-COMe (7), and for-Nle-Leu-Phe-OMe (8) have been studied. Some of these have been found selective towards the activation of different biological responses of human neutrophils. In particular, peptides 2 and 3, which evoke only chemotaxis, are ineffective in enhancing inositol phosphate, as well as cyclic AMP (cAMP) levels. On the contrary, analogues 5 and 7, which induce superoxide anion production and degranulation, but not chemotaxis, significantly increase the levels of the two intracellular messengers, as is the case of the full agonists 1 and 6. The Ca(2+) ionophore A23187 also activates phospholipase C (PLC) and increases the nucleotide levels; when tested in combination with peptide 1 or 5, a supra-additive enhancement of cAMP concentration is obtained. The PLC blocker, U-73122, inhibits the formylpeptide-induced inositol phosphate formation, as well as cAMP increase. Moreover, this drug drastically reduces superoxide anion release triggered by 1 or 5, whereas it inhibits to a much lesser extent neutrophil chemotaxis induced by 1 or 2. Our results suggest that: (i) PLC stimulation is involved in cAMP enhancement by formylpeptides; (ii) the activation of PLC by formylpeptides, in conditions of increased Ca(2+) influx, induces a supra-additive enhancement of the nucleotide; (iii) the inability of pure chemoattractants to significantly alter the PLC activity or cAMP level, differently from full agonists or peptides specific in inducing superoxide anion release, appears as a general property. Thus, the activation of neutrophil PLC seems essential for superoxide anion release, but less involved in the chemotactic response.
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Affiliation(s)
- M E Ferretti
- Dipartimento di Biologia, Sezione di Fisiologia Generale, via L. Borsari 46, Università di Ferrara, 44100, Ferrara, Italy
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11
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Fabbri E, Spisani S, Barbin L, Biondi C, Buzzi M, Traniello S, Zecchini GP, Ferretti ME. Studies on fMLP-receptor interaction and signal transduction pathway by means of fMLP-OMe selective analogues. Cell Signal 2000; 12:391-8. [PMID: 10889468 DOI: 10.1016/s0898-6568(00)00075-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
For-Thp-Leu-Ain-OMe ([Thp(1), Ain(3)] fMLP-OMe) (2), for-Met-delta(z)Leu-Phe-OMe ([delta(z)Leu(2)] fMLP-OMe) (3), for-Thp-Leu-Phe-OMe ([Thp(1)] fMLP-OMe) (4), and for-Met-Leu-Ain-OMe ([Ain(3)] fMLP-OMe) (5) are for-Met-Leu-Phe-OMe (fMLP-OMe) (1) analogues which discriminate between different responses of human neutrophils. Peptides 3 and 5, similar to fMLP-OMe, enhance neutrophil cyclic AMP (cAMP) as well as calcium levels, while analogues 2 and 4, which evoke only chemotaxis, do not alter the concentration of these intracellular messengers. When we tested the peptides' ability to displace [3H]-fMLP from its binding sites, the following order of potency was observed: analogue 1 > 3 > 5 > 2 > 4. A particularly low activity at the receptor level characterized analogues 2 and 4. Their low effectiveness was not improved by the addition of cytochalasin B, by different incubation temperatures, or by the absence of endogenous guanine nucleotides, conditions known to influence fMLP receptor fate and functionality. We speculate that, in certain conditions, the fMLP receptor may undergo conformational changes that impede the binding of pure chemoattractants.
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Affiliation(s)
- E Fabbri
- Dipartimento di Biologia, via Selmi 3, Università di Bologna, 40100 Bologna, Italy
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12
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Torrini I, Zecchini GP, Paradisi MP, Lucente G, Mastropietro G, Gavuzzo E, Mazza F, Pochetti G, Traniello S, Spisani S. Modified chemotactic peptides: Synthesis, conformation, and activity of HCO-Thp-Ac6c-Phe-OMe. Biopolymers 1998. [DOI: 10.1002/(sici)1097-0282(199609)39:3<327::aid-bip5>3.0.co;2-q] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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13
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Tuzi A, Rosaria Ciajolo M, Picone D, Crescenzi O, Temussi PA, Fissi A, Pieroni O. 310-Helices, Helix Screw Sense and Screw Sense Reversal in the Dehydro-peptide Boc-Val-ΔPhe-Gly-ΔPhe-Val-OMe. J Pept Sci 1998. [DOI: 10.1002/psc.47.o] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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14
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Fabbri E, Spisani S, Biondi C, Barbin L, Colamussi ML, Cariani A, Traniello S, Torrini I, Ferretti ME. Two for-Met-Leu-Phe-OMe analogues trigger selective neutrophil responses. A differential effect on cytosolic free Ca2+. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1359:233-40. [PMID: 9434129 DOI: 10.1016/s0167-4889(97)00101-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
For-Thp-Leu-Ain-OMe and for-Met-delta(z)Leu-Phe-OMe are two conformationally restricted fMLP-OMe analogues able to discriminate between different biological responses of human neutrophils. In this paper, we demonstrate that the former peptide, which evokes only chemotaxis, does not alter human neutrophil Ca2+ levels. In contrast, for-Met-delta(z)Leu-Phe-OMe, which induces superoxide anion release and degranulation but not chemotaxis, significantly increases the cation concentration. The chelation of Ca2+ in both extracellular and intracellular media abolishes O2- production triggered by for-Met-delta(z)Leu-Phe-OMe, while the same procedure does not affect neutrophil chemotaxis towards for-Thp-Leu-Ain-OMe. We therefore suggest that chemotaxis, unlike superoxide anion release, is independent of Ca2+ enhancement in human neutrophils.
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Affiliation(s)
- E Fabbri
- Dipartimento di Biologia, Università degli Studi, Ferrara, Italy
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15
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Torrini I, Paglialunga Paradisi M, Pagani Zecchini G, Lucente G, Gavuzzo E, Mazza F, Pochetti G, Traniello S, Spisani S. Synthesis, conformation, and biological activity of two fMLP-OMe analogues containing the new 2-[2'-(methylthio)ethyl]methionine residue. Biopolymers 1997; 42:415-26. [PMID: 9283291 DOI: 10.1002/(sici)1097-0282(19971005)42:4<415::aid-bip5>3.0.co;2-t] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The new C alpha-tetrasubstituted alpha-amino acid residue 2-[2'-(methylthio)ethyl]methionine (Dmt) has been introduced into the reference chemotactic tripeptide HCO-Met-Leu-Phe-OMe (fMLP-OMe) in place of the leucine or methionine, respectively. The biological activity of the new analogues [Dmt2]fMLP-OMe (2) and [Dmt1]fMLP-OMe (3) has been determined; whereas 2 is active toward human neutrophils, stimulating directed migration, superoxide anion generation, and lysozyme release, 3 results practically inactive in all tested assays. A conformational analysis on 2 and 3 has been performed in solution by using ir absorption and 1H-nmr. The conformation of 2 was also examined in the crystal by x-ray diffraction methods. Both 2 and 3 adopt fully extended conformation in correspondence with the Dmt residue. Biological and conformational results are discussed and compared with related previously studied models.
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Affiliation(s)
- I Torrini
- Dipartimento di Studi Farmaceutici, Università La Sapienza, Roma, Italy
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16
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Mitra SN, Dey S, Karthikeyan S, Singh TP. Design of specific structures using alpha,beta-dehydro-phenylalanine residues: synthesis, crystal structure, and molecular conformation of Boc-L-Val-delta Phe-delta Phe-L-Val-delta Phe-delta Phe-L-Val-OCH3, a 3(10)-helical heptapeptide. Biopolymers 1997; 41:97-105. [PMID: 8986122 DOI: 10.1002/(sici)1097-0282(199701)41:1<97::aid-bip9>3.0.co;2-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The peptide design using alpha,beta-dehydro-residues has wide applications. To design an extensive 3(10)-helical conformation, a heptapeptide Boc-L-Val-delta Phe-delta Phe-L-Val-delta Phe-delta Phe-L-Val-OCH3, with a repeat of two consecutive delta Phe residues has been synthesized using an azlactone method in solution phase. This is the first design using a repeat of two consecutive delta Phe residues. It is observed that the delta Phe in a sequence of two consecutive delta Phe residues, adopts only one set of phi, psi values, i.e., +/- 60 degrees, +/- 30 degrees, thus making it a specific design tool. The peptide crystallized from its solution in a methanol-water mixture in the space group P2(1) with a = 10.159(5)A, b = 20.057(2)A, c = 14.448(3)A, beta = 99.41(2)degrees, V = 2904(2)A3. The structure has been determined by direct methods and refined to an R value of 0.048 for 5404 observed [I > or = 3 sigma(I)] reflections. The structure consists of a heptapeptide Boc-L-Val-delta Phe-delta Phe-L-Val-delta Phe-delta Phe-L-Val-OCH3 and a solvent methanol molecule in the asymmetric unit. All peptide units in the structure are trans. As a result of six overlapping type III beta-turns formed involving seven residues and five intramolecular 4-->1 hydrogen bonds, the peptide adopts a right-handed 3(10)-helical conformation with more than two complete helical turns. It is noteworthy that starting from the Boc group to the C-terminal residue of Val, the 3(10)-helical structure is maintained well. The carbonyl oxygen atom of the Boc group is the first acceptor whereas the carbonyl oxygen atom of Val4 is the last acceptor in the helical structure of the peptide. The side chains of four delta Phe residues in this helical arrangement exist in a slightly staggered arrangement. The solvent methanol molecule interacts through its hydroxyl group and forms two intermolecular hydrogen bonds, one as a donor with a C-terminal CO group of delta Phe6 and second as an acceptor with the NH group of delta Phe2 from the N-terminal region of the peptide. Thus the solvent molecule plays a significant role in promoting a head-to-tail packing of 3(10)-helices of the peptide. There are no lateral hydrogen bonds between the helices, but there exist several van der Waals interactions involving the hydrophobic side chains of peptide molecules.
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Affiliation(s)
- S N Mitra
- Department of Biophysics All India Institute of Medical Sciences New Delhi, India
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17
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Pagani Zecchini G, Paglialunga Paradisi M, Torrini I, Lucente G, Mastropietro G, Paci M, Spisani S. Chemotactic peptide analogues. Centrally constrained chemotactic N-formyltripeptides: synthesis, conformation, and activity of two new analogues. Arch Pharm (Weinheim) 1996; 329:517-23. [PMID: 9038418 DOI: 10.1002/ardp.19963291202] [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: 02/03/2023]
Abstract
The role exercised by the central residue of the chemotactic N-formyltripeptide HCO-Met-Leu-Phe-OMe (fMLP-OMe) in controlling both the backbone conformation and the biochemical activity is the subject of recent interest. Here, two new centrally constrained fMLP-OMe analogues, namely HCO-Met-azaPro-Phe-OMe (4) and HCO-Met-(gamma-lactam)-Phe-OMe (6) have been synthesized and their CDCI3 solution conformation and activity have been studied. The azapeptide 4 adopts beta-folded conformation with the azaPro residue at the i+2 position and an intramolecular H-bond involving the formylic oxygen and the Phe NH. The gamma-lactam tripeptide 6 prefers a semi-extended backbone conformation. When tested on human neutrophils both the new models were found practically devoid of biological activity. The role exerted by the NH groups as well as by the conformational preferences is discussed.
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Affiliation(s)
- G Pagani Zecchini
- Dipartimento di Studi Farmaceutici, Università La Sapienza, Roma, Italy
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18
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Torrini I, Pagani Zecchini G, Paglialunga Paradisi M, Lucente G, Mastropietro G, Gavuzzo E, Mazza F, Pochetti G, Traniello S, Spisani S. Modified chemotactic peptides: synthesis, conformation, and activity of HCO-Thp-Ac6c-Phe-OMe. Biopolymers 1996; 39:327-37. [PMID: 8756513 DOI: 10.1002/(sici)1097-0282(199609)39:3%3c327::aid-bip5%3e3.0.co;2-q] [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: 02/02/2023]
Abstract
HCO-Thp-Ac6c-Phe-OMe (3) has been synthesized as a new analogue of the prototypical chemotactic agent HCO-Met-Leu-Phe-OMe (fMLP-OMe). Compound 3 contains 4-aminotetra-hydrothiopyran-4-carboxylic acid (Thp) and 1-aminocyclohexane-1-carboxylic acid (Ac6c) as achiral, conformationally restricted mimics of Met and Leu, respectively. In the crystal, the formyltripeptide adopts an helical conformation at the Thp and Ac6c residues, of the type alpha R and alpha L, respectively, whereas the C-terminal phenylalanine is quasi-extended. A system of two consecutive gamma-turns, centered at the first two residues, better explains the nmr data as compared with an alternative beta-turn structure. The conformation of the new analogue 3 is compared with those of two related peptides containing Thp as N-terminal residue. The biological activity of 3 has been determined on human neutrophils and compared to that of the previously studied model [Ac6c2] fMLP-OMe. While the above analogue is highly active in the superoxide anion production, the new tripeptide 3 is practically unable to elicit any of the tested biological activities.
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Affiliation(s)
- I Torrini
- Dipartimento di Studi Farmaceutici, Università La Sapienza, Roma, Italy
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19
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Spisani S, Pareschi MC, Buzzi M, Colamussi ML, Biondi C, Traniello S, Pagani Zecchini G, Paglialunga Paradisi M, Torrini I, Ferretti ME. Effect of cyclic AMP level reduction on human neutrophil responses to formylated peptides. Cell Signal 1996; 8:269-77. [PMID: 8842527 DOI: 10.1016/0898-6568(96)00049-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The increase in human neutrophil cyclic adenosine monophosphate (cAMP) levels evoked by formylated peptides is significantly reduced in the presence of MDL 12330A, SQ 22536, GDPssS and clonidine, which inhibit the adenylyl cyclase system by acting at different sites in this enzyme complex. A similar effect is exerted by adenosine deaminase and dipyridamole, which alter the extracellular adenosine concentration. Neutrophil preincubation with adenylyl cyclase inhibitors or dipyridamole reduces chemotaxis and superoxide anion production triggered by peptides; adenosine deaminase, on the contrary, has no effect on neutrophil responses. Our results seem to indicate that: (1) the peptide-induced increase in neutrophil cAMP is due mainly to an action on the adenylyl cyclase system; (2) an enhancement of this cyclic nucleotide, even slight and necessarily transient, is required for chemotaxis and O2 production induced in neutrophils by formylated peptides; and (3) cAMP does not represent the crucial second messenger for adenosine in the modulation of neutrophil responses.
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Affiliation(s)
- S Spisani
- Dipartimento di Biochimica e Biologia Molecolare, Università Degli Studi di Ferrara, Italy
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20
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Singh TP, Kaur P. Conformation and design of peptides with alpha,beta-dehydro-amino acid residues. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1996; 66:141-65. [PMID: 9175427 DOI: 10.1016/s0079-6107(97)85628-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- T P Singh
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India
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21
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Abstract
A CD investigation of eleven dehydropeptides is reported. The compounds investigated include tri-, tetra-, hepta-, and octapeptides and contain one, two, or three dehydro-phenylalanine (deltaPhe) residues. The peptides showed different CD profiles depending on chain length, position, and number of dehydro residues. The CD data very much complemented that provided by nmr studies, confirming the conformational preference for beta-bend structures in small peptides (tripeptides), and 3(10)-helical or alpha-helical structures in longer peptides. The secondary structures were stable in chloroform solution and were denatured by addition of trifluoroacetic acid. Solvent titration experiments performed by measuring CD as a function of solvent composition provided evidence that the order < or > disorder conformational changes occurred as cooperative transitions.
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Affiliation(s)
- O Pieroni
- CNR-Institute of Biophysics, Pisa, Italy
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22
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Tuzi A, Ciajolo MR, Picone D, Crescenzi O, Temussi PA, Fissi A, Pieroni O. 3(10)-Helices, helix screw sense and screw sense reversal in the dehydro-peptide Boc-Val-delta Phe-Gly-delta Phe-Val-OMe. J Pept Sci 1996; 2:47-58. [PMID: 9225245 DOI: 10.1002/psc.47] [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: 02/04/2023]
Abstract
The pentapeptide Boc-Val-delta Phe-Gly-delta Phe-Val-OME, containing two dehydro-phenylalanine (delta Phe) residues, has been synthesized and its structure investigated. In the crystalline state, the molecule adopts a right-handed 3(10)-helical conformation stabilized by two intramolecular hydrogen bonds between CO of Val1 and NH of delta Phe4, and between CO of delta Phe2 and NH of Val5, respectively. NMR measurements are consistent with the presence of 3(10)-helical structures also in acetonitrile and dimethylsulphoxide solution: the distances between backbone protons estimated from NOE connectivities are in overall agreement with those observed in the solid state; the chemical shifts of the amide protons show the smaller temperature coefficients for the NHs that in solid state are involved in intramolecular hydrogen bonds. The CD spectra in acetonitrile, chloroform, methanol and dimethylsulphoxide display exciton couplets of bands corresponding to the delta Phe electronic transition at 280 nm; the sign of the bands is consistent with the presence of helical structures having a prevalent left-handed screw sense. Addition of 1,1,1,3,3,3-hexafluoro-propan-2-ol gives rise to the gradual appearance of a couplet of opposite sign, suggesting the helix reversal from left-handed sense to right-handed sense. The conformational behaviour is discussed on the basis of the specific sequence of the peptide.
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Affiliation(s)
- A Tuzi
- Department of Chemistry, University of Naples, Italy
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23
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Zecchini GP, Paradisi MP, Torrini I, Spisani S. Chemotactic peptide analogues. Synthesis and chemotactic activity of N-formyl-Met-Leu-Phe analogues containing (S)-phenylalaninol derivatives. Arch Pharm (Weinheim) 1995; 328:673-6. [PMID: 7487425 DOI: 10.1002/ardp.19953280908] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The synthesis and the biological activity towards human neutrophils of some N-formyl-Met-Leu-Phe-OMe analogues containing (S)-phenylalaninol (Pheol) or its derivatives in place of the native phenylalanine are reported. While the analogue containing Pheol (4) was found to be devoid of significant biological activity, its esters 3 and 5, although inactive as chemoattractants, are able to strongly stimulate superoxide production and are active with a lower efficacy in the lysozyme release.
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Affiliation(s)
- G P Zecchini
- Dipartimento di Studi Farmaceutici, Università La Sapienza, Roma, Italy
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24
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Rzeszotarska B, Karolak-Wojciechowska J, Broda MA, Gałdecki Z, Trzeźwińska B, Kozioł AE. Conformational investigation of alpha, beta-dehydropeptides. Part VI. Molecular and crystal structure of benzyloxycarbonylglycyl-(Z)-dehydrophenylalanine. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1994; 44:313-9. [PMID: 7875932 DOI: 10.1111/j.1399-3011.1994.tb01014.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The structure of a peptide containing C-terminal dehydrophenylalanine, Z-Gly-(Z)-delta Phe (C19H18N2O5, MW = 354) was determined from single-crystal X-ray diffraction data. Needle-shaped crystals were grown from a 1:1 mixture of methanol-acetone in the monoclinic space group P2(1) with a = 14.717(4), b = 4.941(2), c = 12.073(4) A, beta = 103.72(4) degrees; V = 852.86(8) A3, Z = 2 and Dc = 1.32 g cm-3. The structure was solved by direct methods using SHELXS-86 and refined to a final R-index of 0.032 for 1714 observed reflections. The peptide adopts a conformation folded at the glycine residue, and principal torsion angles are omega 0 = -167.6(2) degrees, phi 1 = -71.8(3) degrees, psi 1 = -31.6(4) degrees, omega 1 = -165.7(3) degrees, phi 2 = 65.6(4) degrees, psi 1(2) = -174.4(3) degrees and psi 2(2) = 5.2(4) degrees. Two intermolecular hydrogen bonds, N1-H...O0' and O2-H...O1', join the folded molecules into columns and link columns to each other, respectively. FTIR spectroscopy shows the presence of three hydrogen bonds. This third one has been interpreted as an intramolecular hydrogen bond of the N2-H...N1 type.
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Affiliation(s)
- B Rzeszotarska
- Department of Organic Chemistry, Pedagogical University of Opole, Poland
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25
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Sharma P, Narula P, Singh TP. alpha,beta-Dehydro-amino acid residues in the design of peptide structures: synthesis, crystal structure, and molecular conformation of two homologous peptides-N-Ac-dehydro-Phe-L-Leu-OCH3 and N-Ac-dehydro-Phe-NorVal-OCH3. Biopolymers 1994; 34:1243-9. [PMID: 7948736 DOI: 10.1002/bip.360340912] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The dehydro-residue containing peptides N-Ac-dehydro-Phe-L-Leu-OCH3 (I) and N-Ac-dehydro-Phe-NorVal-OCH3 (II) were synthesized by the usual workup procedures. The peptides crystallize from their solutions in methanol in space group P6(5): (I) a = b = 12.528(2) A, c = 21.653(5) A; (II) a = b = 12.532(2) A, c = 21.695(4) A. The structures were determined by direct methods. Both peptides adopt similar conformations with phi,psi of dehydro-Phe as follows: (I) -57.0(5) degrees and -37.0(5) degrees; (II) -56.0(5), degrees, and -37.5(5) degrees. The observed data on dehydro-Phe when placed at the (i + 1) position show that the phi,psi values of dehydro-Phe are either -60 degrees, 140 degrees or -60 degrees, -30 degrees. The conformation of -60 degrees, 140 degrees can be accommodated only with a flexible residue at the (i + 2) position while the phi,psi values of -60 degrees, -30 degrees are obtained with a bulky residue at the (i + 2) position as in the present structures. The molecules are packed in a helical way along the c axis. These are held by two strong intermolecular hydrogen bonds involving both NH as donors and acetyl group and dehydro-Phe oxygen atoms as acceptors.
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Affiliation(s)
- P Sharma
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi
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26
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Torrini I, Pagani Zecchini G, Paglialunga Paradisi M, Lucente G, Gavuzzo E, Mazza F, Pochetti G, Traniello S, Spisani S. Modified chemotactic peptides: synthesis, crystal conformation, and activity of For-Hse(Me)-Leu-Phe-OMe. Biopolymers 1994; 34:1-9. [PMID: 8110962 DOI: 10.1002/bip.360340102] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The presence of the sulfur atom of the methionine side chain exerts significant effects at different levels on biochemical behavior of chemotactic N-formylpeptides. In order to acquire more information on this point, the synthesis, the conformation in the crystal, and the activity of For-Hse(Me)-Leu-Phe-OMe (2)--an oxygen analogue of For-Met-Leu-Phe-OMe (fMLP-OMe) containing the O-methyl-L-homoserine in place of the native methionine at position 1--is reported. The new analogue 2 adopts a conformation that is extended at the first two residues and folded at the C-terminal phenylalanine. This conformation is different from that of the parent fMLP-OMe and strikingly similar to that adopted by fMLP-OBu(t). The side-chain spatial orientation of 2 corresponds to that adopted by fMLP-OH when cocrystallized with an immunoglobulin possessing binding properties similar to those of neutrophil receptors. When tested on human neutrophils the formylpeptide 2 is more active than the parent in the stimulation of directed mobility and maintains both the granule enzyme release activity and the superoxide anion production.
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Affiliation(s)
- I Torrini
- Dipartimento di Studi Farmaceutici, Università La Sapienza, Roma, Italy
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27
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Ferretti ME, Spisani S, Pareschi MC, Buzzi M, Cavallaro R, Traniello S, Reali E, Torrini I, Paradisi MP, Zecchini GP. Two new formylated peptides able to activate chemotaxis and respiratory burst selectively as tools for studying human neutrophil responses. Cell Signal 1994; 6:91-101. [PMID: 7516692 DOI: 10.1016/0898-6568(94)90064-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Two new For-Met-Leu-Phe-OH (FMLP) methyl ester analogues, For-Thp-Leu-Ain-OMe [Thp1, Ain3] and For-Met-delta zLeu-Phe-OMe [delta zLeu2], able to activate selectively chemotaxis and superoxide anion (O2-) release, respectively modulate intracellular cyclic AMP (cAMP) levels in different ways. FMLP and [delta zLeu2] enhance human neutrophil cAMP levels per se, and this effect is potentiated by Ro 201724, a non-xanthinic phosphodiesterase (PDE) inhibitor, whereas it is counteracted by 3-isobutyl-1-methyl-xanthine (IBMX), a blocker of both phosphodiesterase and adenosine receptors. In contrast, [Thp1, Ain3] is ineffective. However, no formylated peptides influence cAMP phosphodiesterase activity. Neutrophil preincubation with Ro 201724 or IBMX drastically reduces chemotaxis and superoxide anion (O2-) production triggered by peptides. Our results suggest that: (1) peptide-induced cAMP increase is probably indirect, and due mainly to the action on adenosine-sensitive adenylate cyclase; (2) formylated peptide, endowed solely with chemotactic activity is unable to increase neutrophil cAMP concentration; (3) cAMP elevation may represent a feed-back mechanism to inhibit the physiological responses induced by formylated peptides.
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Affiliation(s)
- M E Ferretti
- Istituto di Fisiologia Generale, Università degli Studi di Ferrara, Italy
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28
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Benedetti E. X-ray crystallography of peptides: the contributions of the Italian laboratories. Biopolymers 1996; 40:3-44. [PMID: 8541447 DOI: 10.1002/(sici)1097-0282(1996)40:1<3::aid-bip2>3.0.co;2-#] [Citation(s) in RCA: 131] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The review article summarizes the most relevant solid state structural and conformational results obtained in the laboratories involved in Italy in the studies of synthetic and natural peptides by x-ray diffraction analyses. Some of the topics will include research studies carried out in other European countries, whereas in other cases studies carried out in Italy will be included in other review articles included in this volume. The review deals with peptides containing symmetrically achiral and unsymmetrically chiral C alpha,alpha-dialkylated glycine residues, peptides containing beta-alanine residues, alpha,beta-dehydroamino acid residues, and aminosuccinyl residues, peptides containing the thioamide surrogate, heterochiral peptides and several bioactive peptides systems with the proposed relationships between function and structure.
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Affiliation(s)
- E Benedetti
- Biocrystallography Centre, CNR, University of Napoli Federico II, Italy
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29
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Jain R, Chauhan VS. Conformational characteristics of peptides containing alpha, beta-dehydroamino acid residues. Biopolymers 1996; 40:105-19. [PMID: 8541443 DOI: 10.1002/(sici)1097-0282(1996)40:1<105::aid-bip5>3.0.co;2-#] [Citation(s) in RCA: 104] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The structural preferences of synthetic peptides containing alpha, beta-dehydroamino acid residues, as determined by theoretical studies, x-ray diffraction analyses, and spectroscopic studies, are reviewed. The role of delta ZPhe residues in stabilizing type II beta-turn structures in small peptides and in nucleating helical structure in longer peptides is exemplified by several crystal as well as solution structural studies. From the few studies reported so far it appears that delta ZLeu influences the peptide backbone, much like the delta ZPhe residue, whereas delta Ala prefers the extended conformation, suggesting that the nature of beta substituents might influence the conformation restriction behavior of the dehydroresidues. Conformational studies on synthetic peptides containing delta E, delta ZAbu, and delta Val have also been described.
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