Mapping key interactions in the dimerization process of HBHA from Mycobacterium tuberculosis, insights into bacterial agglutination

AbstractHBHA is a cell-surface protein implicated in the dissemination of Mycobacterium tuberculosis (Mtb) from the site of primary infection. Its N-terminal coiled-coil region is also involved in bacterial agglutination. However, despite the importance of HBHA dimerization in agglutination, protein regions involved in dimerization are hitherto not known. Here, we mapped these regions by coupling peptide synthesis, biochemical and computational analyses, and identified structural determinants for HBHA monomer–monomer recognition. Importantly, we obtained the first molecule able to induce HBHA dimer disaggregation at 37°C, the typical growth temperature of Mtb. This result provides new opportunities towards the development of Mtb anti-aggregation molecules with therapeutic interest.Structured summary of protein interactionsHBHA and HBHA bind by molecular sieving (View interaction)HBHA and H1 peptide bind by competition binding (View Interaction)HBHA and H1ext peptide bind by competition binding (View Interaction)HBHA and H2ext peptide bind by competition binding (View Interaction)HBHA and H2 peptide bind by competition binding (View Interaction)HBHA and H2ext peptide bind by competition binding (View Interaction)HBHA and HBHA bind by blue native page (View interaction

Dissecting the cytochrome P450 OleP substrate specificity: evidence for a preferential substrate

The cytochrome P450 OleP catalyzes the epoxidation of aliphatic carbons on both the aglycone 8.8a-deoxyoleandolide (DEO) and the monoglycosylated L-olivosyl-8.8a-deoxyoleandolide (L-O-DEO) intermediates of oleandomycin biosynthesis. We investigated the substrate versatility of the enzyme. X-ray and equilibrium binding data show that the aglycone DEO loosely fits the OleP active site, triggering the closure that prepares it for catalysis only on a minor population of enzyme. The open-to-closed state transition allows solvent molecules to accumulate in a cavity that forms upon closure, mediating protein–substrate interactions. In silico docking of the monoglycosylated L-O-DEO in the closed OleP–DEO structure shows that the L-olivosyl moiety can be hosted in the same cavity, replacing solvent molecules and directly contacting structural elements involved in the transition. X-ray structures of aglycone-bound OleP in the presence of L-rhamnose confirm the cavity as a potential site for sugar binding. All considered, we propose L-O-DEO as the optimal substrate of OleP, the L-olivosyl moiety possibly representing the molecular wedge that triggers a more efficient structural response upon substrate binding, favoring and stabilizing the enzyme closure before catalysis. OleP substrate versatility is supported by structural solvent molecules that compensate for the absence of a glycosyl unit when the aglycone is bound

Synthesis of temporin L hydroxamate-based peptides and evaluation of their coordination properties with iron (III)

Ferric iron is an essential nutrient for bacterial growth. Pathogenic bacteria synthesize iron-chelating entities known as siderophores to sequestrate ferric iron from host organisms in order to colonize and replicate. The development of antimicrobial peptides (AMPs) conjugated to iron chelators represents a promising strategy for reducing iron availability, inducing bacterial death, and enhancing simultaneously the efficacy of AMPs. Here we designed, synthesized, and characterized three hydroxamate-based peptides Pep-cyc1, Pep-cyc2, and Pep-cyc3, derived from a cyclic temporin L peptide (Pep-cyc) developed previously by some of us. The Fe3+ complex formation of each ligand was characterized by UVvisible spectroscopy, mass spectrometry, IR, and NMR spectroscopies. In addition, the effect of Fe3+ on the stabilization of -helix conformation of hydroxamate-based peptides and the cotton effect were examined by CD spectroscopy. Moreover, the antimicrobial results obtained in vitro on some Gram-negative strains (K. Pneumoniae and E. coli) showed the ability of each peptide to chelate efficaciously Fe3+ obtaining a reduction of MIC values in comparison to their parent peptide Pepcyc. Our results demonstrated that siderophore conjugation could increase the efficacy and selectivity of AMPs used for the treatment of infectious diseases caused by Gram-negative pathogens

Consensus communication strategies to improve doctor-patient relationship in paediatric severe asthma

Background: Asthma is a chronic inflammatory disease that is very common among youth worldwide. The burden of this illness is very high not only considering financial costs but also on emotional and social functioning. Guidelines and many researches recommend to develop a good communication between physicians and children/caregiver and their parents. Nevertheless, a previous Italian project showed some criticalities in paediatric severe asthma management. The consensus gathered together experts in paediatric asthma management, experts in narrative medicine and patient associations with the aim of identify simple recommendation to improve communication strategies. Methods: Participants to the consensus received the results of the project and a selection of narratives two weeks before the meeting. The meeting was structured in plenary session and in three working groups discussing respectively about communication strategies with children, adolescents and parents. The task of each working group was to identify the most effective (DO) and least effective practices (DON' T) for 5 phases of the visit: welcome, comprehension of the context, emotions management, duration and end of the visit and endurance of the relationship. Results: Participants agreed that good relationships translate into positive outcomes and reached consensus on communication strategies to implement in the different phase of relationships. Conclusions: The future challenges identified by the participants are the dissemination of this Consensus document and the implementation of effective communication strategies to improve the management of pediatric asthma

Richieste info e statistiche di accesso al sito Web dell’Osservatorio Vesuviano (INGV) in relazione alla sequenza sismica dell’Abruzzo - aprile 2009

Immediatamente dopo l’evento di M 5.8 verificatosi in Abruzzo in prossimità dell’Aquila il 6 aprile 2009 alle ore 03:33 (ora locale) il sito web dell’Osservatorio Vesuviano (INGV) ha registrato un improvviso aumento degli accessi che, con diverse modulazioni, è perdurato per tutto il mese di aprile. Contemporaneamente numerose richieste di informazioni sono pervenute all’indirizzo di posta [email protected]. L’Osservatorio Vesuviano non ha prodotto sul proprio sito documenti specifici sull’evento maggiore né sulla sequenza dell’Aquilano, rimandando con un link alla pagina del portale nazionale. Dall’analisi delle statistiche degli accessi e dalle mail ricevute emerge che l’incremento degli accessi è stato determinato dalla consultazione dei “Segnali Sismici in Tempo Reale” in linea sul sito dal 2000. Dalla lettura delle mail si rileva che l’applicazione riscuote grande consenso presso gli utenti ed è recepita come un segnale di affidabilità e trasparenza dell’operato dell’intero Istituto.Istituto Nazionale di Geofisica e Vulcanologia, sezione di Napoli Osservatorio VesuvianoPublished1.1. TTC - Monitoraggio sismico del territorio nazionale5.10. TTC - Sistema webope

Richieste info e statistiche di accesso al sito Web dell’Osservatorio Vesuviano (INGV) in relazione alla sequenza sismica dell’Abruzzo - aprile 2009

Immediatamente dopo l’evento di M 5.8 verificatosi in Abruzzo in prossimità dell’Aquila il 6 aprile 2009 alle ore 03:33 (ora locale) il sito web dell’Osservatorio Vesuviano (INGV) ha registrato un improvviso aumento degli accessi che, con diverse modulazioni, è perdurato per tutto il mese di aprile. Contemporaneamente numerose richieste di informazioni sono pervenute all’indirizzo di posta [email protected]. L’Osservatorio Vesuviano non ha prodotto sul proprio sito documenti specifici sull’evento maggiore né sulla sequenza dell’Aquilano, rimandando con un link alla pagina del portale nazionale. Dall’analisi delle statistiche degli accessi e dalle mail ricevute emerge che l’incremento degli accessi è stato determinato dalla consultazione dei “Segnali Sismici in Tempo Reale” in linea sul sito dal 2000. Dalla lettura delle mail si rileva che l’applicazione riscuote grande consenso presso gli utenti ed è recepita come un segnale di affidabilità e trasparenza dell’operato dell’intero Istituto

HE-LHC: The High-Energy Large Hadron Collider – Future Circular Collider Conceptual Design Report Volume 4

In response to the 2013 Update of the European Strategy for Particle Physics (EPPSU), the Future Circular Collider (FCC) study was launched as a world-wide international collaboration hosted by CERN. The FCC study covered an energy-frontier hadron collider (FCC-hh), a highest-luminosity high-energy lepton collider (FCC-ee), the corresponding 100 km tunnel infrastructure, as well as the physics opportunities of these two colliders, and a high-energy LHC, based on FCC-hh technology. This document constitutes the third volume of the FCC Conceptual Design Report, devoted to the hadron collider FCC-hh. It summarizes the FCC-hh physics discovery opportunities, presents the FCC-hh accelerator design, performance reach, and staged operation plan, discusses the underlying technologies, the civil engineering and technical infrastructure, and also sketches a possible implementation. Combining ingredients from the Large Hadron Collider (LHC), the high-luminosity LHC upgrade and adding novel technologies and approaches, the FCC-hh design aims at significantly extending the energy frontier to 100 TeV. Its unprecedented centre-of-mass collision energy will make the FCC-hh a unique instrument to explore physics beyond the Standard Model, offering great direct sensitivity to new physics and discoveries