RESUMO
The matrix protein (M) of paramyxoviruses plays a key role in determining virion morphology by directing viral assembly and budding. Here, we report the crystal structure of the human metapneumovirus M at 2.8 Å resolution in its native dimeric state. The structure reveals the presence of a high-affinity Ca²âº binding site. Molecular dynamics simulations (MDS) predict a secondary lower-affinity site that correlates well with data from fluorescence-based thermal shift assays. By combining small-angle X-ray scattering with MDS and ensemble analysis, we captured the structure and dynamics of M in solution. Our analysis reveals a large positively charged patch on the protein surface that is involved in membrane interaction. Structural analysis of DOPC-induced polymerization of M into helical filaments using electron microscopy leads to a model of M self-assembly. The conservation of the Ca²âº binding sites suggests a role for calcium in the replication and morphogenesis of pneumoviruses.
Assuntos
Proteínas de Ligação ao Cálcio/química , Cálcio/química , Metapneumovirus/química , Proteínas da Matriz Viral/química , Vírion/química , Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Humanos , Metapneumovirus/fisiologia , Metapneumovirus/ultraestrutura , Microscopia Eletrônica , Simulação de Dinâmica Molecular , Fosfatidilcolinas/química , Multimerização Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Espalhamento a Baixo Ângulo , Termodinâmica , Proteínas da Matriz Viral/genética , Proteínas da Matriz Viral/metabolismo , Vírion/fisiologia , Vírion/ultraestrutura , Montagem de Vírus , Replicação Viral , Difração de Raios XRESUMO
A new strain of avian paramyxovirus type 6 (APMV-6), JL, has been isolated from mallard ducks in China, and its complete genome has been sequenced and analyzed. This work is the first announced complete genome sequence of APMV-6 from mallards.
Assuntos
Patos/virologia , Genoma Viral/genética , Metapneumovirus/genética , Animais , Sequência de Bases , China , Metapneumovirus/ultraestrutura , Microscopia Eletrônica/veterinária , Dados de Sequência Molecular , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Análise de Sequência de DNA/veterinária , Especificidade da EspécieRESUMO
The human metapneumovirus (hMPV) is a new Pneumovirinae related to the avian metapneumovirus type C. hMPV genome differs from human respiratory syncytial virus (RSV) genome by the gene order and the lack of nonstructural genes. Two genetic sub-groups and four sub-types of hMPV are identified. hMPV infections evolve as regular winter outbreaks which have roughly the same size and overlaping RSV epidemics. Among hospitalized children in Caen, hMPV is detected in 9.7% of the cases after RSV (37%), rhinovirus (18%), influenza virus (14.5%), adenovirus (9%), and parainfluenza virus (5%). Most of hMPV infections are observed in children suffering from bronchiolitis, but the localization to lower respiratory tract and the severity of the disease are less frequent in comparison with RSV infections. hMPV is very difficult to isolate using cell culture. Up to now, the only way for hMPV diagnosis was the TS-CRP assays. But the recent apparition of direct antigenic tests allows us to get a fair, rapid, and economic diagnostic tool.
Assuntos
Metapneumovirus/patogenicidade , Criança , Diagnóstico Diferencial , Surtos de Doenças , França/epidemiologia , Genoma Viral , Humanos , Influenza Humana/epidemiologia , Metapneumovirus/classificação , Metapneumovirus/genética , Metapneumovirus/ultraestrutura , Orthomyxoviridae , Infecções por Paramyxoviridae/epidemiologia , Filogenia , Infecções por Retroviridae/epidemiologia , Vírus do Sarcoma de RousRESUMO
Human metapneumovirus is an emerging human respiratory pathogen first discovered in 2001. It clinically resembles respiratory syncytial virus, can cause both upper and lower tract disease, and has been associated with serious illness in the young, among the immunosuppressed, and in the chronically ill. Cough and congestion are frequently reported, and respiratory failure may occur. Initial infection occurs during early childhood, and repeated infections throughout life impart only transient immunity. Diagnosis is by reverse transcription-polymerase chain reaction or rising serologic titers. No commercial laboratory tests or treatments are available. Primary care physicians should maintain vigilance for outbreaks of newly discovered and emerging respiratory illnesses.
Assuntos
Doenças Transmissíveis Emergentes/virologia , Metapneumovirus/isolamento & purificação , Infecções por Paramyxoviridae/virologia , Infecções Respiratórias/virologia , Doença Aguda , Doenças Transmissíveis Emergentes/diagnóstico , Humanos , Metapneumovirus/ultraestrutura , Infecções por Paramyxoviridae/diagnóstico , Infecções Respiratórias/diagnósticoRESUMO
Human metapneumovirus (HMPV) was recently identified in The Netherlands and was linked to acute respiratory tract illness. In this study, 11 isolates from 10 patients with respiratory disease from Quebec, Canada, were tested by a reverse-transcriptase polymerase chain reaction based on the fusion protein gene. Identified sequences were consistent with HMPV. The patients were 2 months to 87 years of age (median age, 58 years) and presented with acute respiratory tract illness during the winter season. Sequence studies of the nucleocapsid, fusion, and polymerase genes identified 2 main lineages of HMPV and cocirculation of both lineages during the same year. These findings support a previous finding that HMPV is a human respiratory pathogen that merits further study.