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1.
Biochim Biophys Acta Mol Cell Biol Lipids ; 1869(3): 159464, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38360201

RESUMEN

The Ebola virus matrix protein VP40 is responsible for the formation of the viral matrix by localizing at the inner leaflet of the human plasma membrane (PM). Various lipid types, including PI(4,5)P2 (i.e. PIP2) and phosphatidylserine (PS), play active roles in this process. Specifically, the negatively charged headgroups of both PIP2 and PS interact with the basic residues of VP40 and stabilize it at the membrane surface, allowing for eventual egress. Phosphatidic acid (PA), resulting from the enzyme phospholipase D (PLD), is also known to play an active role in viral development. In this work, we performed a biophysical and computational analysis to investigate the effects of the presence of PA on the membrane localization and association of VP40. We used coarse-grained molecular dynamics simulations to quantify VP40 hexamer interactions with the inner leaflet of the PM. Analysis of the local distribution of lipids shows enhanced lipid clustering when PA is abundant in the membrane. We observed that PA lipids have a similar role to that of PS lipids in VP40 association due to the geometry and charge. Complementary experiments performed in cell culture demonstrate competition between VP40 and a canonical PA-binding protein for the PM. Also, inhibition of PA synthesis reduced the detectable budding of virus-like particles. These computational and experimental results provide new insights into the early stages of Ebola virus budding and the role that PA lipids have on the VP40-PM association.


Asunto(s)
Ebolavirus , Fiebre Hemorrágica Ebola , Humanos , Ebolavirus/metabolismo , Fiebre Hemorrágica Ebola/metabolismo , Membrana Celular/metabolismo , Simulación de Dinámica Molecular , Lípidos/análisis
2.
J Lipid Res ; 65(3): 100512, 2024 03.
Artículo en Inglés | MEDLINE | ID: mdl-38295986

RESUMEN

Ebola virus (EBOV) causes severe hemorrhagic fever in humans and is lethal in a large percentage of those infected. The EBOV matrix protein viral protein 40 kDa (VP40) is a peripheral binding protein that forms a shell beneath the lipid bilayer in virions and virus-like particles (VLPs). VP40 is required for virus assembly and budding from the host cell plasma membrane. VP40 is a dimer that can rearrange into oligomers at the plasma membrane interface, but it is unclear how these structures form and how they are stabilized. We therefore investigated the ability of VP40 to form stable oligomers using in vitro and cellular assays. We characterized two lysine-rich regions in the VP40 C-terminal domain (CTD) that bind phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) and play distinct roles in lipid binding and the assembly of the EBOV matrix layer. The extensive analysis of VP40 with and without lipids by hydrogen deuterium exchange mass spectrometry revealed that VP40 oligomers become extremely stable when VP40 binds PI(4,5)P2. The PI(4,5)P2-induced stability of VP40 dimers and oligomers is a critical factor in VP40 oligomerization and release of VLPs from the plasma membrane. The two lysine-rich regions of the VP40 CTD have different roles with respect to interactions with plasma membrane phosphatidylserine (PS) and PI(4,5)P2. CTD region 1 (Lys221, Lys224, and Lys225) interacts with PI(4,5)P2 more favorably than PS and is important for VP40 extent of oligomerization. In contrast, region 2 (Lys270, Lys274, Lys275, and Lys279) mediates VP40 oligomer stability via lipid interactions and has a more prominent role in release of VLPs.


Asunto(s)
Ebolavirus , Fiebre Hemorrágica Ebola , Humanos , Ebolavirus/metabolismo , Fiebre Hemorrágica Ebola/metabolismo , Lisina/metabolismo , Sitios de Unión , Lípidos , Unión Proteica
3.
Int Immunopharmacol ; 111: 109109, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35926269

RESUMEN

Marburgvirus (MARV), a member of the Filovirus family, causes severe hemorrhagic fever in humans. Currently, there are no approved vaccines or post exposure treatment methods available against MARV. With the aim of identifying vaccine candidates against MARV, we employ different sequence-based computational methods to predict the MHC-I and MHC-II T-cell epitopes as well as B-cell epitopes for the complete MARV genome. We analyzed the variations in the predicted epitopes among four MARV variants, the Lake Victoria, Angola, Musoke, and Ravn. We used a consensus approach to identify several epitopes, including novel epitopes, and narrowed down the selection based on different parameters such as antigenicity and IC50 values. The selected epitopes can be used in various vaccine constructs that give effective antibody responses. The MHC-I epitope-allele complexes for GP and NP with favorably low IC50 values were investigated using molecular dynamics computations to determine the molecular details of the epitope-allele complexes. This study provides information for further experimental validation of the potential epitopes and the design and development of MARV vaccines.


Asunto(s)
Enfermedad del Virus de Marburg , Marburgvirus , Vacunas Virales , Alelos , Animales , Epítopos de Linfocito B/genética , Epítopos de Linfocito T/genética , Humanos , Enfermedad del Virus de Marburg/genética , Marburgvirus/genética
4.
J Chem Theory Comput ; 18(1): 516-525, 2022 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-34874159

RESUMEN

There has been an alarming rise in antibacterial resistant infections in recent years due to the widespread use of antibiotics, and there is a dire need for the development of new antibiotics utilizing novel modes of action. Lantibiotics are promising candidates to engage in the fight against resistant strains of bacteria due to their unique modes of action, including interference with cell wall synthesis by binding to lipid II and creating pores in bacterial membranes. In this study, we use atomic-scale molecular dynamics computational studies to compare both the lipid II binding ability and the membrane interactions of five lanthipeptides that are commonly used in antimicrobial research: nisin, Mutacin 1140 (MU1140), gallidermin, NVB302, and NAI107. Among the five peptides investigated, nisin is found to be the most efficient at forming water channels through a membrane, whereas gallidermin and MU1140 are found to be better at binding the lipid II molecules. Nisin's effectiveness in facilitating water transport across the membrane is due to the creation of several different water trajectories along with no significant water delay points along the paths. The shorter peptide deoxyactagardine B (NVB302) was found to not form a water channel. These detailed observations provide insights into the dual mechanisms of the action of lantibiotic peptides and can facilitate the design and development of novel lanthipeptides by strategic placement of different residues.


Asunto(s)
Antibacterianos , Uridina Difosfato Ácido N-Acetilmurámico , Antibacterianos/metabolismo , Bacterias/metabolismo , Simulación de Dinámica Molecular , Uridina Difosfato Ácido N-Acetilmurámico/análogos & derivados , Uridina Difosfato Ácido N-Acetilmurámico/química , Uridina Difosfato Ácido N-Acetilmurámico/metabolismo
5.
Proteins ; 90(2): 340-350, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34431571

RESUMEN

Outbreaks of the Ebola virus (EBOV) continue to occur and while a vaccine and treatment are now available, there remains a dearth of options for those who become sick with EBOV disease. An understanding at the atomic and molecular level of the various steps in the EBOV replication cycle can provide molecular targets for disrupting the virus. An important step in the EBOV replication cycle is the transport of EBOV structural matrix VP40 protein molecules to the plasma membrane inner leaflet, which involves VP40 binding to the host cell's Sec24c protein. Though some VP40 residues involved in the binding are known, the molecular details of VP40-Sec24c binding are not known. We use various molecular computational techniques to investigate the molecular details of how EBOV VP40 binds with the Sec24c complex of the ESCRT-I pathway. We employed different docking programs to identify the VP40-binding site on Sec24c and then performed molecular dynamics simulations to determine the atomic details and binding interactions of the complex. We also investigated how the inter-protein interactions of the complex are affected upon mutations of VP40 amino acids in the Sec24c-binding region. Our results provide a molecular basis for understanding previous coimmunoprecipitation experimental studies. In addition, we found that VP40 can bind to a site on Sec24c that can also bind Sec23 and suggests that VP40 may use the COPII transport mechanism in a manner that may not need the Sec23 protein in order for VP40 to be transported to the plasma membrane.


Asunto(s)
Ebolavirus/metabolismo , Fiebre Hemorrágica Ebola/virología , Proteínas de Transporte Vesicular , Proteínas de la Matriz Viral , Humanos , Unión Proteica , Transporte de Proteínas , Proteínas de Transporte Vesicular/química , Proteínas de Transporte Vesicular/metabolismo , Proteínas de la Matriz Viral/química , Proteínas de la Matriz Viral/metabolismo
6.
Biochem Biophys Res Commun ; 574: 14-19, 2021 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-34425281

RESUMEN

Following the initial surges of the Alpha (B.1.1.7) and the Beta (B.1.351) variants, a more infectious Delta variant (B.1.617.2) is now surging, further deepening the health crises caused by the pandemic. The sharp rise in cases attributed to the Delta variant has made it especially disturbing and is a variant of concern. Fortunately, current vaccines offer protection against known variants of concern, including the Delta variant. However, the Delta variant has exhibited some ability to dodge the immune system as it is found that neutralizing antibodies from prior infections or vaccines are less receptive to binding with the Delta spike protein. Here, we investigated the structural changes caused by the mutations in the Delta variant's receptor-binding interface and explored the effects on binding with the ACE2 receptor as well as with neutralizing antibodies. We find that the receptor-binding ß-loop-ß motif adopts an altered but stable conformation causing separation in some of the antibody binding epitopes. Our study shows reduced binding of neutralizing antibodies and provides a possible mechanism for the immune evasion exhibited by the Delta variant.


Asunto(s)
Enzima Convertidora de Angiotensina 2/inmunología , COVID-19/inmunología , Evasión Inmune/inmunología , Mutación/inmunología , SARS-CoV-2/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Aminoácidos/genética , Aminoácidos/inmunología , Aminoácidos/metabolismo , Enzima Convertidora de Angiotensina 2/genética , Enzima Convertidora de Angiotensina 2/metabolismo , Anticuerpos Antivirales/inmunología , Sitios de Unión/genética , Sitios de Unión/inmunología , COVID-19/metabolismo , COVID-19/virología , Humanos , Evasión Inmune/genética , Simulación de Dinámica Molecular , Mutación/genética , Pruebas de Neutralización , Unión Proteica , Dominios Proteicos , SARS-CoV-2/genética , SARS-CoV-2/metabolismo , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/genética
7.
Viruses ; 13(7)2021 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-34372582

RESUMEN

Ebolavirus (EBOV) is a negative-sense RNA virus that causes severe hemorrhagic fever in humans. The matrix protein VP40 facilitates viral budding by binding to lipids in the host cell plasma membrane and driving the formation of filamentous, pleomorphic virus particles. The C-terminal domain of VP40 contains two highly-conserved cysteine residues at positions 311 and 314, but their role in the viral life cycle is unknown. We therefore investigated the properties of VP40 mutants in which the conserved cysteine residues were replaced with alanine. The C311A mutation significantly increased the affinity of VP40 for membranes containing phosphatidylserine (PS), resulting in the assembly of longer virus-like particles (VLPs) compared to wild-type VP40. The C314A mutation also increased the affinity of VP40 for membranes containing PS, albeit to a lesser degree than C311A. The double mutant behaved in a similar manner to the individual mutants. Computer modeling revealed that both cysteine residues restrain a loop segment containing lysine residues that interact with the plasma membrane, but Cys311 has the dominant role. Accordingly, the C311A mutation increases the flexibility of this membrane-binding loop, changes the profile of hydrogen bonding within VP40 and therefore binds to PS with greater affinity. This is the first evidence that mutations in VP40 can increase its affinity for biological membranes and modify the length of Ebola VLPs. The Cys311 and Cys314 residues therefore play an important role in dynamic interactions at the plasma membrane by modulating the ability of VP40 to bind PS.


Asunto(s)
Ebolavirus/genética , Proteínas de la Matriz Viral/genética , Animales , Células COS , Membrana Celular/metabolismo , Chlorocebus aethiops , Cisteína/genética , Ebolavirus/metabolismo , Humanos , Lípidos/fisiología , Simulación de Dinámica Molecular , Fosfatidilserinas/metabolismo , Polimorfismo de Nucleótido Simple/genética , Unión Proteica , Multimerización de Proteína , Proteínas de la Matriz Viral/metabolismo , Proteínas de la Matriz Viral/ultraestructura , Virión/metabolismo , Ensamble de Virus/genética , Liberación del Virus/genética
8.
J Phys Chem B ; 125(26): 7101-7107, 2021 07 08.
Artículo en Inglés | MEDLINE | ID: mdl-34110159

RESUMEN

The novel coronavirus (SARS-CoV-2) pandemic that started in late 2019 is responsible for hundreds of millions of cases worldwide and millions of fatalities. Though vaccines are available, the virus is mutating to form new strains among which are the variants B.1.1.7 and B.1.351 that demonstrate increased transmissivity and infectivity. In this study, we performed molecular dynamics simulations to explore the role of the mutations in the interaction of the virus spike protein receptor binding domain (RBD) with the host receptor ACE2. We find that the hydrogen bond networks are rearranged in the variants and also that new hydrogen bonds are established between the RBD and ACE2 as a result of mutations. We investigated three variants: the wild-type (WT), B.1.1.7, and B.1.351. We find that the B.1.351 variant (also known as 501Y.V2) shows larger flexibility in the RBD loop segment involving residue K484, yet the RBD-ACE2 complex shows higher stability. Mutations that allow a more flexible interface that can result in a more stable complex may be a factor contributing to the increased infectivity of the mutated variants.


Asunto(s)
COVID-19 , Glicoproteína de la Espiga del Coronavirus , Humanos , Unión Proteica , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/metabolismo
9.
J Biol Chem ; 296: 100796, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34019871

RESUMEN

Marburg virus (MARV) is a lipid-enveloped virus harboring a negative-sense RNA genome, which has caused sporadic outbreaks of viral hemorrhagic fever in sub-Saharan Africa. MARV assembles and buds from the host cell plasma membrane where MARV matrix protein (mVP40) dimers associate with anionic lipids at the plasma membrane inner leaflet and undergo a dynamic and extensive self-oligomerization into the structural matrix layer. The MARV matrix layer confers the virion filamentous shape and stability but how host lipids modulate mVP40 oligomerization is mostly unknown. Using in vitro and cellular techniques, we present a mVP40 assembly model highlighting two distinct oligomerization interfaces: the (N-terminal domain [NTD] and C-terminal domain [CTD]) in mVP40. Cellular studies of NTD and CTD oligomerization interface mutants demonstrate the importance of each interface in matrix assembly. The assembly steps include protein trafficking to the plasma membrane, homo-multimerization that induced protein enrichment, plasma membrane fluidity changes, and elongations at the plasma membrane. An ascorbate peroxidase derivative (APEX)-transmission electron microscopy method was employed to closely assess the ultrastructural localization and formation of viral particles for wildtype mVP40 and NTD and CTD oligomerization interface mutants. Taken together, these studies present a mechanistic model of mVP40 oligomerization and assembly at the plasma membrane during virion assembly that requires interactions with phosphatidylserine for NTD-NTD interactions and phosphatidylinositol-4,5-bisphosphate for proper CTD-CTD interactions. These findings have broader implications in understanding budding of lipid-enveloped viruses from the host cell plasma membrane and potential strategies to target protein-protein or lipid-protein interactions to inhibit virus budding.


Asunto(s)
Enfermedad del Virus de Marburg/virología , Marburgvirus/fisiología , Lípidos de la Membrana/metabolismo , Proteínas de la Matriz Viral/metabolismo , Virión/metabolismo , Animales , Células COS , Membrana Celular/química , Membrana Celular/metabolismo , Chlorocebus aethiops , Células HEK293 , Humanos , Membrana Dobles de Lípidos/química , Membrana Dobles de Lípidos/metabolismo , Enfermedad del Virus de Marburg/metabolismo , Marburgvirus/química , Lípidos de la Membrana/química , Modelos Moleculares , Multimerización de Proteína , Proteínas de la Matriz Viral/química , Virión/química , Ensamble de Virus
10.
Sci Rep ; 10(1): 7667, 2020 05 06.
Artículo en Inglés | MEDLINE | ID: mdl-32376973

RESUMEN

Lassa virus (LASV), a member of the Arenaviridae, is an ambisense RNA virus that causes severe hemorrhagic fever with a high fatality rate in humans in West and Central Africa. Currently, no FDA approved drugs or vaccines are available for the treatment of LASV fever. The LASV glycoprotein complex (GP) is a promising target for vaccine or drug development. It is situated on the virion envelope and plays key roles in LASV growth, cell tropism, host range, and pathogenicity. In an effort to discover new LASV vaccines, we employ several sequence-based computational prediction tools to identify LASV GP major histocompatibility complex (MHC) class I and II T-cell epitopes. In addition, many sequence- and structure-based computational prediction tools were used to identify LASV GP B-cell epitopes. The predicted T- and B-cell epitopes were further filtered based on the consensus approach that resulted in the identification of thirty new epitopes that have not been previously tested experimentally. Epitope-allele complexes were obtained for selected strongly binding alleles to the MHC-I T-cell epitopes using molecular docking and the complexes were relaxed with molecular dynamics simulations to investigate the interaction and dynamics of the epitope-allele complexes. These predictions provide guidance to the experimental investigations and validation of the epitopes with the potential for stimulating T-cell responses and B-cell antibodies against LASV and allow the design and development of LASV vaccines.


Asunto(s)
Mapeo Epitopo , Epítopos/química , Epítopos/inmunología , Fiebre de Lassa/inmunología , Virus Lassa/inmunología , Modelos Moleculares , Alelos , Secuencia de Aminoácidos , Mapeo Epitopo/métodos , Epítopos/genética , Epítopos de Linfocito B/química , Epítopos de Linfocito B/inmunología , Epítopos de Linfocito T/química , Epítopos de Linfocito T/inmunología , Antígenos de Histocompatibilidad Clase I/química , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Fiebre de Lassa/prevención & control , Virus Lassa/genética , Conformación Proteica , Proteínas Virales/química , Proteínas Virales/inmunología , Vacunas Virales/genética , Vacunas Virales/inmunología , Flujo de Trabajo
11.
Pathogens ; 9(5)2020 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-32455873

RESUMEN

The Ebola virus (EBOV) harbors seven genes, one of which is the matrix protein eVP40, a peripheral protein that is sufficient to induce the formation of virus-like particles from the host cell plasma membrane. eVP40 can form different structures to fulfil different functions during the viral life cycle, although the structural dynamics of eVP40 that warrant dimer, hexamer, and octamer formation are still poorly understood. eVP40 has two conserved Trp residues at positions 95 and 191. The role of Trp95 has been characterized in depth as it serves as an important residue in eVP40 oligomer formation. To gain insight into the functional role of Trp191 in eVP40, we prepared mutations of Trp191 (W191A or W191F) to determine the effects of mutation on eVP40 plasma membrane localization and budding as well as eVP40 oligomerization. These in vitro and cellular experiments were complemented by molecular dynamics simulations of the wild-type (WT) eVP40 structure versus that of W191A. Taken together, Trp is shown to be a critical amino acid at position 191 as mutation to Ala reduces the ability of VP40 to localize to the plasma membrane inner leaflet and form new virus-like particles. Further, mutation of Trp191 to Ala or Phe shifted the in vitro equilibrium to the octamer form by destabilizing Trp191 interactions with nearby residues. This study has shed new light on the importance of interdomain interactions in stability of the eVP40 structure and the critical nature of timing of eVP40 oligomerization for plasma membrane localization and viral budding.

12.
Viruses ; 12(4)2020 04 24.
Artículo en Inglés | MEDLINE | ID: mdl-32344654

RESUMEN

Marburg virus (MARV) is a lipid-enveloped negative sense single stranded RNA virus, which can cause a deadly hemorrhagic fever. MARV encodes seven proteins, including VP40 (mVP40), a matrix protein that interacts with the cytoplasmic leaflet of the host cell plasma membrane. VP40 traffics to the plasma membrane inner leaflet, where it assembles to facilitate the budding of viral particles. VP40 is a multifunctional protein that interacts with several host proteins and lipids to complete the viral replication cycle, but many of these host interactions remain unknown or are poorly characterized. In this study, we investigated the role of a hydrophobic loop region in the carboxy-terminal domain (CTD) of mVP40 that shares sequence similarity with the CTD of Ebola virus VP40 (eVP40). These conserved hydrophobic residues in eVP40 have been previously shown to be critical to plasma membrane localization and membrane insertion. An array of cellular experiments and confirmatory in vitro work strongly suggests proper orientation and hydrophobic residues (Phe281, Leu283, and Phe286) in the mVP40 CTD are critical to plasma membrane localization. In line with the different functions proposed for eVP40 and mVP40 CTD hydrophobic residues, molecular dynamics simulations demonstrate large flexibility of residues in the EBOV CTD whereas conserved mVP40 hydrophobic residues are more restricted in their flexibility. This study sheds further light on important amino acids and structural features in mVP40 required for its plasma membrane localization as well as differences in the functional role of CTD amino acids in eVP40 and mVP40.


Asunto(s)
Membrana Celular/metabolismo , Enfermedad del Virus de Marburg/virología , Marburgvirus/fisiología , Mutación , Dominios y Motivos de Interacción de Proteínas , Proteínas de la Matriz Viral/química , Proteínas de la Matriz Viral/metabolismo , Aminoácidos/química , Animales , Células COS , Membrana Celular/química , Chlorocebus aethiops , Células HEK293 , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Lípidos , Modelos Moleculares , Imagen Molecular , Conformación Proteica , Transporte de Proteínas
13.
J Phys Chem B ; 123(43): 9045-9053, 2019 10 31.
Artículo en Inglés | MEDLINE | ID: mdl-31576755

RESUMEN

The Ebola virus (EBOV) is a virulent pathogen that causes severe hemorrhagic fever with a high fatality rate in humans. The EBOV transformer protein VP40 plays crucial roles in viral assembly and budding at the plasma membrane of infected cells. One of VP40's roles is to form the long, flexible, pleomorphic filamentous structural matrix for the virus. Each filament contains three unique interfaces: monomer NTD-NTD to form a dimer, dimer-to-dimer NTD-NTD oligomerization to form a hexamer, and end-to-end hexamer CTD-CTD to build the filament. However, the atomic-level details of conformational flexibility of the VP40 filament are still elusive. In this study, we have performed explicit-solvent, all-atom molecular dynamic simulations to explore the conformational flexibility of the three different interface structures of the filament. Using dynamic network analysis and other calculational methods, we find that the CTD-CTD hexamer interface with weak interdomain amino acid communities is the most flexible, and the NTD-NTD oligomer interface with strong interdomain communities is the least flexible. Our study suggests that the high flexibility of the CTD-CTD interface may be essential for the supple bending of the Ebola filovirus, and such flexibility may present a target for molecular interventions to disrupt the Ebola virus functioning.


Asunto(s)
Membrana Celular/metabolismo , Nucleoproteínas/química , Nucleoproteínas/metabolismo , Multimerización de Proteína , Proteínas del Núcleo Viral/química , Proteínas del Núcleo Viral/metabolismo , Humanos , Simulación de Dinámica Molecular , Conformación Proteica , Dominios y Motivos de Interacción de Proteínas
14.
Phys Chem Chem Phys ; 21(23): 12530-12539, 2019 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-31147666

RESUMEN

The emergence of antibiotic-resistance is a major concern to global human health and identification of novel antibiotics is critical to mitigate the threat. Mutacin 1140 (MU1140) is a promising antimicrobial lanthipeptide and is effective against Gram-positive bacteria. Like nisin, MU1140 targets and sequesters lipid II and interferes with its function, which results in the inhibition of bacterial cell wall synthesis, and leads to bacteria cell lysis. MU1140 contains a structurally similar thioether cage for binding the lipid II pyrophosphate as for nisin. In addition to lipid II binding, nisin is known to form membrane pores. Membrane pore formation and membrane disruption is a common mode of action for many antimicrobial peptides, including gallidermin, a lantibiotic peptide with similar structural features as MU1140. However, whether and how MU1140 and its variants can form permeable membrane pores remains to be demonstrated. In this work, we explored the potential mechanisms of membrane pore formation by performing molecular simulations of the MU1140-lipid II complex in the bacterial membrane. Our results suggest that MU1140-lipid II complexes are able to form water permeating membrane pores. We find that a single chain of MU1140 complexed with lipid II in the transmembrane region can permeate water molecules across the membrane via a single-file water transport mechanism. The ordering of the water molecules in the single-file chain region as well as the diffusion behavior is similar to those observed in other biological water channels. Multiple complexes of MU1140-lipid II in the membrane showed enhanced permeability for the water molecules, as well as a noticeable membrane distortion and lipid relocation, suggesting that a higher concentration of MU1140 assembly in the membrane can cause significant disruption of the bacterial membrane. These investigations provide an atomistic level insight into a novel mode of action for MU1140 that can be exploited to develop optimized peptide variants with improved antimicrobial properties.


Asunto(s)
Bacteriocinas/farmacología , Bacterias Grampositivas/efectos de los fármacos , Simulación de Dinámica Molecular , Péptidos/farmacología , Bacteriocinas/química , Membrana Celular/efectos de los fármacos , Bacterias Grampositivas/citología , Lípidos/química , Lípidos/farmacología , Pruebas de Sensibilidad Microbiana , Péptidos/química , Agua/química
15.
Methods Mol Biol ; 1958: 297-311, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30945225

RESUMEN

A relatively recently discovered class of proteins known as transformer proteins undergo large-scale conformational conversions that change their supersecondary structure. These structural transformations lead to different configurations that perform different functions. We describe computational methods using molecular dynamics simulations that allow the determination of the specific amino acids that facilitate the conformational transformations. These investigations provide guidance on the location and type of amino acid mutations that can either enhance or inhibit the structural transitions that allow transformer proteins to perform multiple functions.


Asunto(s)
Secuencias de Aminoácidos , Biología Computacional/métodos , Proteínas/química , Secuencia de Aminoácidos/genética , Simulación de Dinámica Molecular , Mutación/genética , Multimerización de Proteína , Proteínas/genética
16.
Phys Chem Chem Phys ; 21(10): 5578-5585, 2019 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-30785432

RESUMEN

The Ebola virus (EBOV) is a filamentous lipid-enveloped virus that causes severe hemorrhagic fever with a high fatality rate in humans. The EBOV encodes a glycoprotein that when cleaved, produces the delta peptide. Experimental evidence suggests that the delta peptide functions as a viroporin that enhances virus particle release through the host cell membrane. However, the viroporin forming mechanism of the delta peptide is still not well understood. Guided by experimental information, we have computationally investigated the pore formation by different oligomers of the delta peptide. We have performed all-atom molecular dynamics (MD) simulations in an explicit membrane environment to investigate the pore-forming mechanism and stability of the pores. Our results suggest that the delta peptide forms stable pentameric pores. In addition, the pore is selective with respect to chloride ions, and the disulfide bond formed between Cys-29 and Cys-38 in the C-terminal of the peptide is essential for the pore stabilization and ion permeation. Our study provides helpful information on the pore-forming mechanism of filovirus delta peptides and such structural information can be important in designing and developing molecular modulators that target the delta peptide pore and disrupt the pathology of the Ebola virus.


Asunto(s)
Ebolavirus , Internalización del Virus , Ebolavirus/química , Ebolavirus/metabolismo , Canales Iónicos/metabolismo , Membranas , Simulación de Dinámica Molecular , Proteínas Virales , Virión
17.
Sci Rep ; 8(1): 9776, 2018 06 27.
Artículo en Inglés | MEDLINE | ID: mdl-29950600

RESUMEN

The Ebola filovirus causes severe hemorrhagic fever with a high fatality rate in humans. The primary structural matrix protein VP40 displays transformer-protein characteristics and exists in different conformational and oligomeric states. VP40 plays crucial roles in viral assembly and budding at the plasma membrane of the infected cells and is capable of forming virus-like particles without the need for other Ebola proteins. However, no experimental three-dimensional structure for any filovirus VP40 cylindrical assembly matrix is currently available. Here, we use a protein-protein docking approach to develop cylindrical assembly models for an Ebola virion and also for a smaller structural matrix that does not contain genetic material. These models match well with the 2D averages of cryo-electron tomograms of the authentic virion. We also used all-atom molecular dynamics simulations to investigate the stability and dynamics of the cylindrical models and the interactions between the side-by-side hexamers to determine the amino acid residues that are especially important for stabilizing the hexamers in the cylindrical ring configuration matrix assembly. Our models provide helpful information to better understand the assembly processes of filoviruses and such structural studies may also lead to the design and development of antiviral drugs.


Asunto(s)
Ebolavirus/metabolismo , Fiebre Hemorrágica Ebola/metabolismo , Nucleoproteínas/metabolismo , Proteínas del Núcleo Viral/metabolismo , Membrana Celular/metabolismo , Simulación de Dinámica Molecular , Nucleoproteínas/química , Dominios Proteicos , Proteínas del Núcleo Viral/química
18.
J Phys Chem B ; 122(14): 3782-3789, 2018 04 12.
Artículo en Inglés | MEDLINE | ID: mdl-29519123

RESUMEN

Calcification in bone, cartilage, and cardiovascular tissues involves the release of specialized extracellular vesicles (EVs) that promote mineral nucleation. The small size of the EVs, however, makes molecular level studies difficult, and consequently uncertainty exists on the role and function of these structures in directing mineralization. The lack of mechanistic understanding associated with the initiators of ectopic mineral deposition has severely hindered the development of potential therapeutic options. Here, we used multiscale molecular dynamics simulations to investigate the calcification within the EVs. Results show that Ca2+-HPO42- and phosphatidylserine complexes facilitate the early nucleation. Use of coarse-grained simulations allows investigations of Ca2+-PO43- nucleation and crystallization in the EVs. Systematic variation in the ion-to-water ratio shows that the crystallization and growth strongly depend on the enrichment of the ions and dehydration inside the EVs. Our investigations provide insights into the role of EVs on calcium phosphate mineral nucleation and growth in both physiological and pathological mineralization.


Asunto(s)
Fosfatos de Calcio/química , Vesículas Extracelulares/química , Simulación de Dinámica Molecular , Fosfatos de Calcio/metabolismo , Simulación por Computador , Vesículas Extracelulares/metabolismo
19.
J Biol Chem ; 293(9): 3335-3349, 2018 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-29348171

RESUMEN

Ebola virus (EBOV) is a filamentous lipid-enveloped virus that causes hemorrhagic fever with a high fatality rate. Viral protein 40 (VP40) is the major EBOV matrix protein and regulates viral budding from the plasma membrane. VP40 is a transformer/morpheein that can structurally rearrange its native homodimer into either a hexameric filament that facilitates viral budding or an RNA-binding octameric ring that regulates viral transcription. VP40 associates with plasma-membrane lipids such as phosphatidylserine (PS), and this association is critical to budding from the host cell. However, it is poorly understood how different VP40 structures interact with PS, what essential residues are involved in this association, and whether VP40 has true selectivity for PS among different glycerophospholipid headgroups. In this study, we used lipid-binding assays, MD simulations, and cellular imaging to investigate the molecular basis of VP40-PS interactions and to determine whether different VP40 structures (i.e. monomer, dimer, and octamer) can interact with PS-containing membranes. Results from quantitative analysis indicated that VP40 associates with PS vesicles via a cationic patch in the C-terminal domain (Lys224, 225 and Lys274, 275). Substitutions of these residues with alanine reduced PS-vesicle binding by >40-fold and abrogated VP40 localization to the plasma membrane. Dimeric VP40 had 2-fold greater affinity for PS-containing membranes than the monomer, whereas binding of the VP40 octameric ring was reduced by nearly 10-fold. Taken together, these results suggest the different VP40 structures known to form in the viral life cycle harbor different affinities for PS-containing membranes.


Asunto(s)
Ebolavirus/metabolismo , Fosfatidilserinas/metabolismo , Proteínas de la Matriz Viral/química , Proteínas de la Matriz Viral/metabolismo , Membrana Celular/metabolismo , Ebolavirus/fisiología , Células HEK293 , Humanos , Simulación de Dinámica Molecular , Mutación , Unión Proteica , Dominios Proteicos , Multimerización de Proteína , Estructura Cuaternaria de Proteína , Transporte de Proteínas , Especificidad por Sustrato , Proteínas de la Matriz Viral/genética
20.
Biochem Biophys Res Commun ; 493(1): 176-181, 2017 11 04.
Artículo en Inglés | MEDLINE | ID: mdl-28917841

RESUMEN

Ebola virus infections cause hemorrhagic fever that often results in very high fatality rates. In addition to exploring vaccines, development of drugs is also essential for treating the disease and preventing the spread of the infection. The Ebola virus matrix protein VP40 exists in various conformational and oligomeric forms and is a potential pharmacological target for disrupting the virus life-cycle. Here we explored graphene-VP40 interactions using molecular dynamics simulations and graphene pelleting assays. We found that graphene sheets associate strongly with VP40 at various interfaces. We also found that the graphene is able to disrupt the C-terminal domain (CTD-CTD) interface of VP40 hexamers. This VP40 hexamer-hexamer interface is crucial in forming the Ebola viral matrix and disruption of this interface may provide a method to use graphene or similar nanoparticle based solutions as a disinfectant that can significantly reduce the spread of the disease and prevent an Ebola epidemic.


Asunto(s)
Grafito/química , Nucleoproteínas/química , Nucleoproteínas/ultraestructura , Proteínas del Núcleo Viral/química , Proteínas del Núcleo Viral/ultraestructura , Proteínas de la Matriz Viral/química , Proteínas de la Matriz Viral/ultraestructura , Sitios de Unión , Simulación de Dinámica Molecular , Unión Proteica , Conformación Proteica , Multimerización de Proteína
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