Mario Paglialunga Paradisi
Sapienza University of Rome
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Featured researches published by Mario Paglialunga Paradisi.
Cellular Signalling | 1996
Susanna Spisani; Maria Cristina Pareschi; Marco Buzzi; Maria Luisa Colamussi; Carla Biondi; Serena Traniello; Giampiero Pagani Zecchini; Mario Paglialunga Paradisi; Ines Torrini; Maria Enrica Ferretti
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.
Tetrahedron | 1995
Mario Paglialunga Paradisi; Ines Torrini; Giampiero Pagani Zecchini; Gino Lucente; E. Gavuzzo; Fernando Mazza; G. Pochetti
Abstract 4-Aminotetrahydrothiopyran-4-carboxylic acid (Thp) is an unusual achiral cyclic α,α-disubstituted amino acid mimicking the natural Met residue. The conformational energy map computed for Ac-Thp-NHMe shows that the γ-turn is the lowest minimum. 1 H-NMR and IR studies performed on For-Thp-Leu-OMe ( 2a ), a short peptide unable to give a 4…>1 H-bond, indicate that the γ-turn is adopted in CDCl 3 solution, whereas is not retained in (CD 3 ) 2 SO. An analogous conformational behaviour in solution has been observed for the strictly related For-Ac 6 c-Leu-OMe ( 2b ), containing 1-aminocyclohexane carboxylic acid (Ac 6 c).
Tetrahedron Letters | 1991
Giampiero Pagani Zecchini; Mario Paglialunga Paradisi; Ines Torrini; Gino Lucente; Enrico Gavuzzo; Fernando Mazza; Giorgio Pochetti
Abstract Boc-Pro-Leu-Ψ(NH-SO 2 )-Gly-NH 2 ( 3 ) has been synthesized as the first example of a pseudopeptide incorporating the NH-SO 2 junction. The crystal structure of 3 indicates that the Ψ(NH-SO 2 ) induces a cisoidal (gauche − ) conformation which induces a backbone folding and prevents the H-bonded β-turn found in the parent peptide.
Cellular Signalling | 1994
M.Enrica Ferretti; Susanna Spisani; M.Cristina Pareschi; Marco Buzzi; Roberta Cavallaro; Serena Traniello; Eva Reali; Ines Torrini; Mario Paglialunga Paradisi; Giampiero Pagani Zecchini; Carla Biondi
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.
Organic and Biomolecular Chemistry | 2003
Massimiliano Aschi; Gino Lucente; Fernando Mazza; Adriano Mollica; Enrico Morera; Marianna Nalli; Mario Paglialunga Paradisi
The conformational study of a new group of synthetic peptides containing 4-amino-1,2-dithiolane-4-carboxylic acid (Adt), a cysteine-related achiral residue, has been carried out through a joint application of computational and experimental methodologies. Molecular Dynamics simulations clearly suggest the tendency of this molecule to adopt a gamma-turn conformation in vacuum and help in analyzing the complex and crucial conformational behaviour of the dithiolane ring which appears to preferentially adopt a C(S)-like structure. Electronic structure calculations carried out in solution using the Density Functional Theory also indicate the preservation of the gamma-like folding in apolar solvents and the helix-like one in more polar solvents. A comparison with the achiral 1-aminocycloalkane-1-carboxylic acid (Ac5c) has been carried out using the same computational tools. NMR and IR data on dipeptide derivatives containing the Adt or Ac5c residue show that in chloroform solution all the models prefer a gamma-turn structure, centered at the cyclic residue, stabilized by an intramolecular H-bond, whereas in a more polar solvent, i.e. dimethyl sulfoxide, this folding is not maintained. The experimental conformational studies, extended to N-Boc protected tripeptides, clearly indicate the remarkable tendency of both the five-membered C(alpha)-tetrasubstituted cyclic amino acids Adt and Ac5c to induce the gamma-turn structure also in models able to adopt the beta-bend conformation.
Tetrahedron Letters | 1986
Mario Paglialunga Paradisi; Giampiero Pagani Zecchini; Ines Torrini
Abstract The title triazolide serves as a convenient reagent for higly chemoselective acetylations of aminophenols and hydroxyalkylphenols.
Tetrahedron Letters | 1980
Mario Paglialunga Paradisi; Giampiero Pagani Zecchini; Giorgio Ortar
Abstract The title process has been accomplished by a three-step sequence involving protection of aldehyde as the imine, in situ reduction of ketone with lithium tri- tert -butoxyaluminohydride, and regeneration of aldehyde on hydrolytic work-up.
Bioorganic & Medicinal Chemistry | 1999
Silvana D’Alessio; Carlo Gallina; Enrico Gavuzzo; Cesare Giordano; Barbara Gorini; Fernando Mazza; Mario Paglialunga Paradisi; Gabriella Panini; Giorgio Pochetti; Antonio Sella
Phosphonate analogues of the peptidomimetic N-(Furan-2-yl)carbonyl-Leu-Trp-OH were prepared with the goal of evaluating the effect of phosphonate for carboxylate replacement on binding with snake venom metalloproteinases and MMPs. N-(Furan-2-yl)carbonyl-Leu-L-Trp(P)-(OH)2 showed a 75-fold increase of the inhibiting activity against adamalysin II, a snake venom metalloproteinase structurally related to MMPs and TACE. Both the phosphonate and carboxylate peptidomimetics fit into the active site adopting a retrobinding mode and provide the structural base for a new class of metalloproteinases inhibitors.
Farmaco | 2003
Cesare Giordano; Gino Lucente; Marianna Nalli; Giampiero Pagani Zecchini; Mario Paglialunga Paradisi; Katia Varani; Susanna Spisani
New synthetic analogues of the chemotactic N-formyltripeptide HCO-Met-Leu-Phe-OMe have been synthesized. The reported new models, namely Boc-Met-beta-Ala-Phe-OMe (1), HCO-Met-beta-Ala-Phe-OMe (2), Boc-Met-Tau-Phe-OMe (3), HCO-Met-Tau-Phe-OMe (4) and HCl.Met-Tau-Phe-OMe (5), are characterized by the presence at the central position of a residue of beta-alanine or 2-aminoethanesulfonic acid (taurine) replacing the native L-leucine. Whereas tripeptides 1 and 2 have been found quite inactive as chemoattractants, all the three models containing the Tau residue exhibit a remarkable activity. Superoxide anion production and lysozyme release have been also evaluated and the biological results are discussed together with the conformational preferences of the examined models.
Tetrahedron Letters | 1991
Giampiero Pagani Zecchini; Mario Paglialunga Paradisi; Ines Torrini; Gino Lucente; Enrico Gavuzzo; Fernando Mazza; Giorgio Pochetti; Susanna Spisani
Abstract The title Δ z Leu containing N-formyltripeptide 2 , has been synthesized and found active in the superoxide production whereas inactive in the stimulation of human neutrophil migration. The X-ray crystallographic analysis reveals that 2 adopts a β-turn conformation stabilized by an intramolecular H-bond.