31 research outputs found
PERSONAL DEVELOPMENT WITHIN NEW CONCEPTS EDUCATION
In article the question of a modern Russian labor market of its globalization, of the competition is considered. Into the forefront quality of preparation acts by Highschools of the young specialist. New instruments of training and preparation: distant, electronic, media components are shown. Use of computer technologies allows students to take part in professional engineering competitions BEST, to solve difficult production problems to perform at the Olympiads and conferences.В статье рассматривается вопрос о современном российском рынке труда, его глобализации, конкуренции. На первый план выступает качество подготовки вузами молодого специалиста. Показаны новые инструменты обучения и подготовки: дистанционные, электронные, медийные компоненты. Использование компьютерных технологий позволяет студентам принимать участие в профессиональных, инженерных соревнованиях BEST, решать непростые производственные задачи, выступать на олимпиадах, конференциях
Hijacking the Fusion Complex of Human Parainfluenza Virus as an Antiviral Strategy
The receptor binding protein of parainfluenza virus, hemagglutinin-neuraminidase (HN), is responsible for actively triggering the viral fusion protein (F) to undergo a conformational change leading to insertion into the target cell and fusion of the virus with the target cell membrane. For proper viral entry to occur, this process must occur when HN is engaged with host cell receptors at the cell surface. It is possible to interfere with this process through premature activation of the F protein, distant from the target cell receptor. Conformational changes in the F protein and adoption of the postfusion form of the protein prior to receptor engagement of HN at the host cell membrane inactivate the virus. We previously identified small molecules that interact with HN and induce it to activate F in an untimely fashion, validating a new antiviral strategy. To obtain highly active pretriggering candidate molecules we carried out a virtual modeling screen for molecules that interact with sialic acid binding site II on HN, which we propose to be the site responsible for activating F. To directly assess the mechanism of action of one such highly effective new premature activating compound, PAC-3066, we use cryo-electron tomography on authentic intact viral particles for the first time to examine the effects of PAC-3066 treatment on the conformation of the viral F protein. We present the first direct observation of the conformational rearrangement induced in the viral F protein.IMPORTANCE Paramyxoviruses, including human parainfluenza virus type 3, are internalized into host cells by fusion between viral and target cell membranes. The receptor binding protein, hemagglutinin-neuraminidase (HN), upon binding to its cell receptor, triggers conformational changes in the fusion protein (F). This action of HN activates F to reach its fusion-competent state. Using small molecules that interact with HN, we can induce the premature activation of F and inactivate the virus. To obtain highly active pretriggering compounds, we carried out a virtual modeling screen for molecules that interact with a sialic acid binding site on HN that we propose to be the site involved in activating F. We use cryo-electron tomography of authentic intact viral particles for the first time to directly assess the mechanism of action of this treatment on the conformation of the viral F protein and present the first direct observation of the induced conformational rearrangement in the viral F protein.This work was supported by National Institute of Allergy and Infectious Diseases (NIAID), NIH, grants R01AI031971 and R01AI114736 to A.M. and by USA-Israel Binational Science Foundation (BSF) grant 2017293 to N.B.-T. E.Y. was partially funded by a fellowship from the Edmond J. Safra Center for Bioinformatics at Tel Aviv University. N.B.-T.’s research is supported in part by the Abraham E. Kazan Chair in Structural Biology, Tel Aviv University.S
Inhibiting Human Parainfluenza Virus Infection by Preactivating the Cell Entry Mechanism
Paramyxoviruses, specifically, the childhood pathogen human parainfluenza virus type 3, are internalized into host cells following fusion between the viral and target cell membranes. The receptor binding protein, hemagglutinin (HA)-neuraminidase (HN), and the fusion protein (F) facilitate viral fusion and entry into the cell through a coordinated process involving HN activation by receptor binding, which triggers conformational changes in the F protein to activate it to reach its fusion-competent state. Interfering with this process through premature activation of the F protein has been shown to be an effective antiviral strategy in vitro. Conformational changes in the F protein leading to adoption of the postfusion form of the protein-prior to receptor engagement of HN at the host cell membrane-render the virus noninfectious. We previously identified a small compound (CSC11) that implements this antiviral strategy through an interaction with HN, causing HN to activate F in an untimely process. To assess the functionality of such compounds, it is necessary to verify that the postfusion state of F has been achieved. As demonstrated by Melero and colleagues, soluble forms of the recombinant postfusion pneumovirus F proteins and of their six helix bundle (6HB) motifs can be used to generate postfusion-specific antibodies. We produced novel anti-HPIV3 F conformation-specific antibodies that can be used to assess the functionality of compounds designed to induce F activation. In this study, using systematic chemical modifications of CSC11, we synthesized a more potent derivative of this compound, CM9. Much like CSC11, CM9 causes premature triggering of the F protein through an interaction with HN prior to receptor engagement, thereby preventing fusion and subsequent infection. In addition to validating the potency of CM9 using plaque reduction, fusion inhibition, and binding avidity assays, we confirmed the transition to a postfusion conformation of F in the presence of CM9 using our novel anti-HPIV3 conformation-specific antibodies. We present both CM9 and these newly characterized postfusion antibodies as novel tools to explore and develop antiviral approaches. In turn, these advances in both our molecular toolset and our understanding of HN-F interaction will support development of more-effective antivirals. Combining the findings described here with our recently described physiologically relevant ex vivo system, we have the potential to inform the development of therapeutics to block viral infection.IMPORTANCE Paramyxoviruses, including human parainfluenza virus type 3, are internalized into host cells by fusion between viral and target cell membranes. The receptor binding protein, hemagglutinin-neuraminidase (HN), and the fusion protein (F) facilitate viral fusion and entry into cells through a process involving HN activation by receptor binding, which triggers conformational changes in F to activate it to reach its fusion-competent state. Interfering with this process through premature activation of the F protein may be an effective antiviral strategy in vitro We identified and optimized small compounds that implement this antiviral strategy through an interaction with HN, causing HN to activate F in an untimely fashion. To address that mechanism, we produced novel anti-HPIV3 F conformation-specific antibodies that can be used to assess the functionality of compounds designed to induce F activation. Both the novel antiviral compounds that we present and these newly characterized postfusion antibodies are novel tools for the exploration and development of antiviral approaches.This work was supported by NIH/National Institute of Allergy and Infectious Diseases (NIAID) grants R01AI031971 and R01AI114736 to A.M.S
Hijacking the fusion complex of human parainfluenza virus as an antiviral strategy
The receptor binding protein of parainfluenza virus, hemagglutinin-neuraminidase (HN), is responsible for actively triggering the viral fusion protein (F) to undergo a conformational change leading to insertion into the target cell and fusion of the virus with the target cell membrane. For proper viral entry to occur, this process must occur when HN is engaged with host cell receptors at the cell surface. It is possible to interfere with this process through premature activation of the F protein, distant from the target cell receptor. Conformational changes in the F protein and adoption of the postfusion form of the protein prior to receptor engagement of HN at the host cell membrane inactivate the virus. We previously identified small molecules that interact with HN and induce it to activate F in an untimely fashion, validating a new antiviral strategy. To obtain highly active pretriggering candidate molecules we carried out a virtual modeling screen for molecules that interact with sialic acid binding site II on HN, which we propose to be the site responsible for activating F. To directly assess the mechanism of action of one such highly effective new premature activating compound, PAC-3066, we use cryo-electron tomography on authentic intact viral particles for the first time to examine the effects of PAC-3066 treatment on the conformation of the viral F protein. We present the first direct observation of the conformational rearrangement induced in the viral F protein. IMPORTANCE Paramyxoviruses, including human parainfluenza virus type 3, are internalized into host cells by fusion between viral and target cell membranes. The receptor binding protein, hemagglutinin-neuraminidase (HN), upon binding to its cell receptor, triggers conformational changes in the fusion protein (F). This action of HN activates F to reach its fusion-competent state. Using small molecules that interact with HN, we can induce the premature activation of F and inactivate the virus. To obtain highly active pretriggering compounds, we carried out a virtual modeling screen for molecules that interact with a sialic acid binding site on HN that we pro-pose to be the site involved in activating F. We use cryo-electron tomography of authentic intact viral particles for the first time to directly assess the mechanism of action of this treatment on the conformation of the viral F protein and present the first direct observation of the induced conformational rearrangement in the viral F protein