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2,215 results on '"ASCENZI, Paolo"'

12. Nitric Oxide Binding Geometry in Heme-Proteins: Relevance for Signal Transduction.

Author

De Simone, Giovanna, di Masi, Alessandra, Sbardella, Diego, Ascenzi, Paolo, and Coletta, Massimiliano

Subjects
HEMOPROTEINS, NITRIC oxide, CELLULAR signal transduction, CARRIER proteins, DIATOMIC molecules, HEME
Abstract

Nitric oxide (NO) synthesis, signaling, and scavenging is associated to relevant physiological and pathological events. In all tissues and organs, NO levels and related functions are regulated at different levels, with heme proteins playing pivotal roles. Here, we focus on the structural changes related to the different binding modes of NO to heme-Fe(II), as well as the modulatory effects of this diatomic messenger on heme-protein functions. Specifically, the ability of heme proteins to bind NO at either the distal or proximal side of the heme and the transient interchanging of the binding site is reported. This sheds light on the regulation of O2 supply to tissues with high metabolic activity, such as the retina, where a precise regulation of blood flow is necessary to meet the demand of nutrients. [ABSTRACT FROM AUTHOR]

Published
2024
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18. Metabolic profile of human parathyroid adenoma

Author

di Masi, Alessandra, Leboffe, Loris, Sodo, Armida, Tabacco, Gaia, Cesareo, Roberto, Sbroscia, Marco, Giovannoni, Isabella, Taffon, Chiara, Crucitti, Pierfilippo, Longo, Filippo, Manfrini, Silvia, Ricci, Maria Antonietta, Ascenzi, Paolo, Crescenzi, Anna, and Palermo, Andrea

Published
2020
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22. Human Serum Albumin Is an Essential Component of the Host Defense Mechanism Against Clostridium difficile Intoxication

Author

di Masi, Alessandra, Leboffe, Loris, Polticelli, Fabio, Tonon, Federica, Zennaro, Cristina, Caterino, Marianna, Stano, Pasquale, Fischer, Stephan, Hägele, Marlen, Müller, Martin, Kleger, Alexander, Papatheodorou, Panagiotis, Nocca, Giuseppina, Arcovito, Alessandro, Gori, Andrea, Ruoppolo, Margherita, Barth, Holger, Petrosillo, Nicola, Ascenzi, Paolo, and Di Bella, Stefano

Published
2018

29. Mechanism of Peroxynitrite Interaction with Ferric M. tuberculosisNitrobindin: A Computational Study

Author

Messias, Andresa, Capece, Luciana, De Simone, Giovanna, Coletta, Massimo, Ascenzi, Paolo, and Estrin, Darío A.

Abstract

Nitrobindins (Nbs) are all-β-barrel heme proteins present along the evolutionary ladder. They display a highly solvent-exposed ferric heme group with the iron atom being coordinated by the proximal His residue and a water molecule at the distal position. Ferric nitrobindins (Nb(III)) play a role in the conversion of toxic peroxynitrite (ONOO–) to harmless nitrate, with the value of the second-order rate constant being similar to those of most heme proteins. The value of the second-order rate constant of Nbs increases as the pH decreases; this suggests that Nb(III) preferentially reacts with peroxynitrous acid (ONOOH), although ONOO–is more nucleophilic. In this work, we shed light on the molecular basis of the ONOO–and ONOOH reactivity of ferric Mycobacterium tuberculosisNb (Mt-Nb(III)) by dissecting the ligand migration toward the active site, the water molecule release, and the ligand binding process by computer simulations. Classical molecular dynamics simulations were performed by employing a steered molecular dynamics approach and the Jarzynski equality to obtain ligand migration free energy profiles for both ONOO–and ONOOH. Our results indicate that ONOO–and ONOOH migration is almost unhindered, consistent with the exposed metal center of Mt-Nb(III). To further analyze the ligand binding process, we computed potential energy profiles for the displacement of the Fe(III)-coordinated water molecule using a hybrid QM/MM scheme at the DFT level and a nudged elastic band approach. These results indicate that ONOO–exhibits a much larger barrier for ligand displacement than ONOOH, suggesting that water displacement is assisted by protonation of the leaving group by the incoming ONOOH.

Published
2024
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31. Thyroid cancer diagnosis by Raman spectroscopy

Author

Sbroscia, Marco, Di Gioacchino, Michael, Ascenzi, Paolo, Crucitti, Pierfilippo, di Masi, Alessandra, Giovannoni, Isabella, Longo, Filippo, Mariotti, Davide, Naciu, Anda Mihaela, Palermo, Andrea, Taffon, Chiara, Verri, Martina, Sodo, Armida, Crescenzi, Anna, and Ricci, Maria Antonietta

Published
2020
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33. Nitrophorins and nitrobindins: structure and function

Author

De Simone Giovanna, Ascenzi Paolo, di Masi Alessandra, and Polticelli Fabio

Subjects
function, nitrobindin, nitrophorin, structure, Biology (General), QH301-705.5
Abstract

Classical all α-helical globins are present in all living organisms and are ordered in three lineages: (i) flavohemoglobins and single domain globins, (ii) protoglobins and globin coupled sensors and (iii) truncated hemoglobins, displaying the 3/3 or the 2/2 all α-helical fold. However, over the last two decades, all β-barrel and mixed α-helical-β-barrel heme-proteins displaying heme-based functional properties (e.g. ligand binding, transport and sensing) closely similar to those of all α-helical globins have been reported. Monomeric nitrophorins (NPs) and α1-microglobulin (α1-m), belonging to the lipocalin superfamily and nitrobindins (Nbs) represent prototypical heme-proteins displaying the all β-barrel and mixed α-helical-β-barrel folds. NPs are confined to the Reduviidae and Cimicidae families of Heteroptera, whereas α1-m and Nbs constitute heme-protein families spanning bacteria to Homo sapiens. The structural organization and the reactivity of the stable ferric solvent-exposed heme-Fe atom suggest that NPs and Nbs are devoted to NO transport, storage and sensing, whereas Hs-α1-m participates in heme metabolism. Here, the structural and functional properties of NPs and Nbs are reviewed in parallel with those of sperm whale myoglobin, which is generally taken as the prototype of monomeric globins.

Published
2017
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