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Open Access
Abstract: The most advanced antiviral molecules addressing major SARS-CoV-2 targets (Main protease, Spike protein, and RNA polymerase), compared with proteins of other human pathogenic coronaviruses, may have a short-lasting clinical efficacy. Accumulating knowledge on the mechanisms underlying the target structural basis, its mutational progression, and the related biological significance to virus replication allows envisaging the development of better-targeted therapies in the context of COVID-19 epidemic and future coronavirus outbreaks. The identification of evolutionary patterns based solely on sequence information analysis for those targets can provide meaningful insights into the molecular basis of host–pathogen interactions and adaptation, leading to drug resistance phenomena. Herein, we will explore how the study of observed and predicted mutations may offer valuable suggestions for the application of the so-called “synthetic lethal” strategy to SARS-CoV-2 Main protease and Spike protein. The synergy between genetics evidence and drug discovery may prioritize the development of novel long-lasting antiviral agents.
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Mar 2023
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Open Access
Abstract: Protozoan parasites are responsible for several harmful and widespread human diseases that cause high morbidity and mortality. Currently available treatments have serious limitations due to poor efficiency, strong adverse effects, and high cost. Hence, the identification of new targets and the development of specific drug therapies against parasitic diseases are urgent needs. Heat shock protein 90 (HSP90) is an ATP-dependent molecular chaperone that plays a key role in parasite survival during the various differentiation stages, spread over the vector insect and the human host, which they undergo during their life cycle. The N-terminal domain (NTD) of HSP90, containing the main determinants for ATPase activity, represents the most druggable domain for inhibitor targeting. The molecules investigated on parasite HSP90 are mainly developed from known inhibitors of the human counterpart, and they have strong limitations due to selectivity issues, accounting for the high conservation of the ATP-binding site between the parasite and human proteins. The current review highlights the recent structural progress made to support the rational design of new molecules able to effectively block the chaperone activity of parasite HSP90.
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Nov 2022
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I04-Macromolecular Crystallography
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Diamond Proposal Number(s):
[21741, 29907]
Open Access
Abstract: The field of targeted protein degradation, through the control of the ubiquitin–proteasome system (UPS), is progressing considerably; to exploit this new therapeutic modality, the proteolysis targeting chimera (PROTAC) technology was born. The opportunity to use PROTACs engaging of new E3 ligases that can hijack and control the UPS system could greatly extend the applicability of degrading molecules. To this end, here we show a potential application of the ELIOT (E3 LIgase pocketOme navigaTor) platform, previously published by this group, for a scaffold-repurposing strategy to identify new ligands for a novel E3 ligase, such as TRIM33. Starting from ELIOT, a case study of the cross-relationship using GRID Molecular Interaction Field (MIF) similarities between TRIM24 and TRIM33 binding sites was selected. Based on the assumption that similar pockets could bind similar ligands and considering that TRIM24 has 12 known co-crystalised ligands, we applied a scaffold-repurposing strategy for the identification of TRIM33 ligands exploiting the scaffold of TRIM24 ligands. We performed a deeper computational analysis to identify pocket similarities and differences, followed by docking and water analysis; selected ligands were synthesised and subsequently tested against TRIM33 via HTRF binding assay, and we obtained the first-ever X-ray crystallographic complexes of TRIM33α with three of the selected compounds.
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Nov 2022
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I04-Macromolecular Crystallography
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Alice
Legru
,
Federica
Verdirosa
,
Yen
Vo-Hoang
,
Giusy
Tassone
,
Filippo
Vascon
,
Caitlyn A.
Thomas
,
Filomena
Sannio
,
Giuseppina
Corsica
,
Manuela
Benvenuti
,
Georges
Feller
,
Rémi
Coulon
,
Francesca
Marcoccia
,
Savannah Rowane
Devente
,
Ezeddine
Bouajila
,
Catherine
Piveteau
,
Fabrice
Leroux
,
Rebecca
Deprez-Poulain
,
Benoît
Deprez
,
Patricia
Licznar-Fajardo
,
Michael W.
Crowder
,
Laura
Cendron
,
Cecilia
Pozzi
,
Stefano
Mangani
,
Jean-Denis
Docquier
,
Jean-François
Hernandez
,
Laurent
Gavara
Diamond Proposal Number(s):
[21741]
Abstract: Metallo-β-lactamases (MBLs) contribute to the resistance of Gram-negative bacteria to carbapenems, last-resort antibiotics at hospital, and MBL inhibitors are urgently needed to preserve these important antibacterial drugs. Here, we describe a series of 1,2,4-triazole-3-thione-based inhibitors displaying an α-amino acid substituent, which amine was mono- or disubstituted by (hetero)aryl groups. Compounds disubstituted by certain nitrogen-containing heterocycles showed submicromolar activities against VIM-type enzymes and strong NDM-1 inhibition (Ki = 10–30 nM). Equilibrium dialysis, native mass spectrometry, isothermal calorimetry (ITC), and X-ray crystallography showed that the compounds inhibited both VIM-2 and NDM-1 at least partially by stripping the catalytic zinc ions. These inhibitors also displayed a very potent synergistic activity with meropenem (16- to 1000-fold minimum inhibitory concentration (MIC) reduction) against VIM-type- and NDM-1-producing ultraresistant clinical isolates, including Enterobacterales and Pseudomonas aeruginosa. Furthermore, selected compounds exhibited no or moderate toxicity toward HeLa cells, favorable absorption, distribution, metabolism, excretion (ADME) properties, and no or modest inhibition of several mammalian metalloenzymes.
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Nov 2022
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I04-Macromolecular Crystallography
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Stefano
Barbera
,
Luisa
Raucci
,
Giusy
Tassone
,
Laura
Tinti
,
Filippo
Prischi
,
Annalisa
Santucci
,
Maurizio
Mongiat
,
Gian Marco
Tosi
,
Federico
Galvagni
,
Anna
Dimberg
,
Cecilia
Pozzi
,
Maurizio
Orlandini
Diamond Proposal Number(s):
[21741]
Abstract: Blocking the signaling activated by the plasma membrane receptor CD93 has recently been demonstrated a useful tool in antiangiogenic treatment and oncotherapy. In the proliferating endothelium, CD93 regulates cell adhesion, migration, and vascular maturation, yet it is unclear how CD93 interacts with the extracellular matrix activating signaling pathways involved in the vascular remodeling. Here for the first time we show that in endothelial cells CD93 is structured as a dimer and that this oligomeric form is physiologically instrumental for the binding of CD93 to its ligand Multimerin-2. Crystallographic X-ray analysis of recombinant CD93 reveals the crucial role played by the C-type lectin-like and sushi-like domains in arranging as an antiparallel dimer to achieve a functional binding state, providing key information for the future design of new drugs able to hamper CD93 function in neovascular pathologies.
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Oct 2022
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I04-Macromolecular Crystallography
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Diamond Proposal Number(s):
[29907]
Open Access
Abstract: Heat shock protein 90 (Hsp90) is a ubiquitous molecular chaperone that stabilizes client proteins in a folded and functional state. It is composed of two identical and symmetrical subunits and each monomer consists of three domains, the N-terminal (NTD), the middle (MD), and the C-terminal domain (CTD). Since the chaperone activity requires ATP hydrolysis, molecules able to occupy the ATP-binding pocket in the NTD act as Hsp90 inhibitors, leading to client protein degradation and cell death. Therefore, human Hsp90 represents a validated target for developing new anticancer drugs. Since protozoan parasites use their Hsp90 to trigger important transitions between different stages of their life cycle, this protein also represents a profitable target in anti-parasite drug discovery. Nevertheless, the development of molecules able to selectively target the ATP-binding site of protozoan Hsp90 is challenging due to the high homology with the human Hsp90 NTD (hHsp90-NTD). In a previous work, a series of potent Hsp90 inhibitors based on a 1,4,5-trisubstituted 1,2,3-triazole scaffold was developed. The most promising inhibitor of the series, JMC31, showed potent Hsp90 binding and antiproliferative activity in NCI-H460 cells in the low-nanomolar range. In this work, we present the structural characterization of hHsp90-NTD in complex with JMC31 through X-ray crystallography. In addition, to elucidate the role of residue 112 on the ligand binding and its exploitability for the development of selective inhibitors, we investigated the crystal structures of hHsp90-NTD variants (K112R and K112A) in complex with JMC31.
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Aug 2022
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I04-Macromolecular Crystallography
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Federica
Verdirosa
,
Laurent
Gavara
,
Laurent
Sevaille
,
Giusy
Tassone
,
Giuseppina
Corsica
,
Alice
Legru
,
Georges
Feller
,
Giulia
Chelini
,
Paola S.
Mercuri
,
Silvia
Tanfoni
,
Filomena
Sannio
,
Manuela
Benvenuti
,
Giulia
Cerboni
,
Filomena
De Luca
,
Ezeddine
Bouajila
,
Yen
Vo Hoang
,
Patricia
Licznar-Fajardo
,
Moreno
Galleni
,
Cecilia
Pozzi
,
Stefano
Mangani
,
Jean-Denis
Docquier
,
Jean-François
Hernandez
Diamond Proposal Number(s):
[21741]
Abstract: Metallo-β-lactamases (MBLs) are increasingly involved as a major mechanism of resistance to carbapenems in relevant opportunistic Gram-negative pathogens. Unfortunately, clinically efficient MBL inhibitors still represent an unmet medical need . We previously reported several series of compounds based on the 1,2,4-triazole-3-thione scaffold. In particular, Schiff bases formed between diversely 5-substituted-4-amino compounds and 2-carboxybenzaldehyde were broad-spectrum inhibitors of VIM-type, NDM-1 and IMP-1 MBLs. Unfortunately, they were unable to restore antibiotic susceptibility of MBL-producing bacteria, probably because of poor penetration and/or susceptibility to hydrolysis. To improve their microbiological activity, we developed compounds where the hydrazone-like bond of the Schiff bases was replaced by a stable ethyl link. This small change resulted in a narrower inhibition spectrum, as all compounds were poorly or not inhibiting NDM-1 and IMP-1, but some showed a significantly better activity on VIM-type enzymes, with K i values in the μM to sub-μM range. The resolution of the crystallographic structure of VIM-2 in complex with one inhibitor yielded valuable information about their binding mode. Interestingly, several compounds were shown to restore the β-lactam susceptibility of K. pneumoniae clinical isolates. In addition, selected compounds were found to be devoid of toxicity toward human cells at high concentration, thus showing promising safety.
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Jan 2022
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I03-Macromolecular Crystallography
I04-Macromolecular Crystallography
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Giusy
Tassone
,
Marco
Paolino
,
Cecilia
Pozzi
,
Annalisa
Reale
,
Laura
Salvini
,
Gianluca
Giorgi
,
Maurizio
Orlandini
,
Federico
Galvagni
,
Stefano
Mangani
,
Xuchun
Yang
,
Benedetta
Carlotti
,
Fausto
Ortica
,
Loredana
Latterini
,
Massimo
Olivucci
,
Andrea
Cappelli
Diamond Proposal Number(s):
[15832, 21741]
Abstract: The use of light-responsive proteins to control both living or synthetic cells, is at the core of the expanding fields of optogenetics and synthetic biology. It is thus apparent that a richer reaction toolbox for the preparation of such systems is of fundamental importance. Here, we provide a proof-of-principle demonstration that Morita-Baylis-Hillman adducts can be employed to perform a facile site-specific, irreversible and diastereoselective click-functionalization of a lysine residue buried into a lipophilic binding pocket and yielding an unnatural chromophore with an extended π-system. In doing so we effectively open the path to the in vitro preparation of a library of synthetic proteins structurally reminiscent of xanthopsin eubacterial photoreceptors. We argue that such library, made of variable unnatural chromophores inserted in an easy to mutate and crystallize retinoic acid transporter, significantly expand the scope of the recently introduced rhodopsin mimics as both optogenetic and "lab-on-a-molecule" tools.
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Oct 2021
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I04-Macromolecular Crystallography
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Alice
Legru
,
Federica
Verdirosa
,
Jean-François
Hernandez
,
Giusi
Tassone
,
Filomena
Sannio
,
Manuela
Benvenuti
,
Pierre-Alexis
Conde
,
Guillaume
Bossis
,
Caitlyn A.
Thomas
,
Michael W.
Crowder
,
Melissa
Dillenberger
,
Katja
Becker
,
Cecilia
Pozzi
,
Stefano
Mangani
,
Jean-Denis
Docquier
,
Laurent
Gavara
Diamond Proposal Number(s):
[21741]
Abstract: Metallo-β-lactamases (MBLs) are important contributors of Gram-negative bacteria resistance to β-lactam antibiotics. MBLs are highly worrying because of their carbapenemase activity, their rapid spread in major human opportunistic pathogens while no clinically useful inhibitor is available yet. In this context, we are exploring the potential of compounds based on the 1,2,4-triazole-3-thione scaffold as an original ligand of the di-zinc active sites of MBLs, and diversely substituted at its positions 4 and 5. Here, we present a new series of compounds substituted at the 4-position by a thioether-containing alkyl chain with a carboxylic and/or an aryl group at its extremity. Several compounds showed broad-spectrum inhibition with Ki values in the μM to sub-μM range against VIM-type enzymes, NDM-1 and IMP-1. The presence of the sulfur and of the aryl group was important for the inhibitory activity and the binding mode of a few compounds in VIM-2 was revealed by X-ray crystallography. Importantly, in vitro antibacterial susceptibility assays showed that several inhibitors were able to potentiate the activity of meropenem on Klebsiella pneumoniae clinical isolates producing VIM-1 or VIM-4, with a potentiation effect of up to 16-fold. Finally, a selected compound was found to only moderately inhibit the di-zinc human glyoxalase II, and several showed no or only moderate toxicity toward several human cells, thus favourably completing a promising behaviour.
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Oct 2021
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I03-Macromolecular Crystallography
I04-Macromolecular Crystallography
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Abstract: Ferritins are nanocage proteins that store iron ions in their central cavity as hydrated ferric oxide biominerals. In mammals, further the L (light) and H (heavy) chains constituting cytoplasmic maxi-ferritins, an additional type of ferritin has been identified, the mitochondrial ferritin (MTF). Human MTF (hMTF) is a functional homopolymeric H-like ferritin performing the ferroxidase activity in its ferroxidase site (FS), in which Fe(II) is oxidized to Fe(III) in the presence of dioxygen. To better investigate its ferroxidase properties, here we performed time-lapse X-ray crystallography analysis of hMTF, providing structural evidence of how iron ions interact with hMTF and of their binding to the FS. Transient iron binding sites, populating the pathway along the cage from the iron entry channel to the catalytic center, were also identified. Furthermore, our kinetic data at variable iron loads indicate that the catalytic iron oxidation reaction occurs via a diferric peroxo intermediate followed by the formation of ferric-oxo species, with significant differences with respect to human H-type ferritin.
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Aug 2021
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