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1.
Viruses ; 11(8)2019 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-31416162

RESUMO

A metatranscriptomic study of RNA viruses in cold-blooded vertebrates identified two related viruses from frogfish (Antennarius striatus) that represent a new genus Antennavirus in the family Arenaviridae (Order: Bunyavirales). Computational analyses were used to identify features common to class I viral fusion proteins (VFPs) in antennavirus glycoproteins, including an N-terminal fusion peptide, two extended alpha-helices, an intrahelical loop, and a carboxyl terminal transmembrane domain. Like mammarenavirus and hartmanivirus glycoproteins, the antennavirus glycoproteins have an intracellular zinc-binding domain and a long virion-associated stable signal peptide (SSP). The glycoproteins of reptarenaviruses are also class I VFPs, but do not contain zinc-binding domains nor do they encode SSPs. Divergent evolution from a common progenitor potentially explains similarities of antennavirus, mammarenavirus, and hartmanivirus glycoproteins, with an ancient recombination event resulting in a divergent reptarenavirus glycoprotein.


Assuntos
Infecções por Arenaviridae/veterinária , Arenaviridae/metabolismo , Doenças dos Peixes/virologia , Proteínas do Envelope Viral/química , Proteínas do Envelope Viral/metabolismo , Proteínas Virais de Fusão/metabolismo , Zinco/metabolismo , Sequência de Aminoácidos , Animais , Arenaviridae/química , Arenaviridae/genética , Infecções por Arenaviridae/virologia , Filogenia , Domínios Proteicos , Sinais Direcionadores de Proteínas , Proteômica , Alinhamento de Sequência , Proteínas do Envelope Viral/genética , Proteínas Virais de Fusão/química , Proteínas Virais de Fusão/genética
2.
PLoS Pathog ; 13(5): e1006400, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28505175

RESUMO

Cap-snatching was first discovered in influenza virus. Structures of the involved domains of the influenza virus polymerase, namely the endonuclease in the PA subunit and the cap-binding domain in the PB2 subunit, have been solved. Cap-snatching endonucleases have also been demonstrated at the very N-terminus of the L proteins of mammarena-, orthobunya-, and hantaviruses. However, a cap-binding domain has not been identified in an arena- or bunyavirus L protein so far. We solved the structure of the 326 C-terminal residues of the L protein of California Academy of Sciences virus (CASV), a reptarenavirus, by X-ray crystallography. The individual domains of this 37-kDa fragment (L-Cterm) as well as the domain arrangement are structurally similar to the cap-binding and adjacent domains of influenza virus polymerase PB2 subunit, despite the absence of sequence homology, suggesting a common evolutionary origin. This enabled identification of a region in CASV L-Cterm with similarity to a cap-binding site; however, the typical sandwich of two aromatic residues was missing. Consistent with this, cap-binding to CASV L-Cterm could not be detected biochemically. In addition, we solved the crystal structure of the corresponding endonuclease in the N-terminus of CASV L protein. It shows a typical endonuclease fold with an active site configuration that is essentially identical to that of known mammarenavirus endonuclease structures. In conclusion, we provide evidence for a presumably functional cap-snatching endonuclease in the N-terminus and a degenerate cap-binding domain in the C-terminus of a reptarenavirus L protein. Implications of these findings for the cap-snatching mechanism in arenaviruses are discussed.


Assuntos
Infecções por Arenaviridae/virologia , Arenaviridae/enzimologia , Endonucleases/metabolismo , Modelos Moleculares , Arenaviridae/química , Arenaviridae/genética , Cristalografia por Raios X , Endonucleases/química , Endonucleases/genética , Conformação Proteica , Domínios Proteicos , Capuzes de RNA , Proteínas Virais/química , Proteínas Virais/genética , Proteínas Virais/metabolismo
3.
Virol Sin ; 31(5): 380-394, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27562602

RESUMO

Mammarenaviruses, including lethal pathogens such as Lassa virus and Junín virus, can cause severe hemorrhagic fever in humans. Entry is a key step for virus infection, which starts with binding of the envelope glycoprotein (GP) to receptors on target cells and subsequent fusion of the virus with target cell membranes. The GP precursor is synthesized as a polypeptide, and maturation occurs by two cleavage events, yielding a tripartite GP complex (GPC) formed by a stable signal peptide (SSP), GP1 and GP2. The unique retained SSP interacts with GP2 and plays essential roles in virion maturation and infectivity. GP1 is responsible for binding to the cell receptor, and GP2 is a class I fusion protein. The native structure of the tripartite GPC is unknown. GPC is critical for the receptor binding, membrane fusion and neutralization antibody recognition. Elucidating the molecular mechanisms underlining the structure-function relationship of the three subunits is the key for understanding their function and can facilitate novel avenues for combating virus infections. This review summarizes the basic aspects and recent research of the structure-function relationship of the three subunits. We discuss the structural basis of the receptor-binding domain in GP1, the interaction between SSP and GP2 and its role in virion maturation and membrane fusion, as well as the mechanism by which glycosylation stabilizes the GPC structure and facilitates immune evasion. Understanding the molecular mechanisms involved in these aspects will contribute to the development of novel vaccines and treatment strategies against mammarenaviruses infection.


Assuntos
Infecções por Arenaviridae/virologia , Arenaviridae/metabolismo , Proteínas do Envelope Viral/química , Proteínas do Envelope Viral/metabolismo , Animais , Arenaviridae/química , Arenaviridae/genética , Humanos , Proteínas do Envelope Viral/genética
4.
Biomol NMR Assign ; 2(1): 81-4, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18958179

RESUMO

The arenavirus protein Z from Lassa fever virus was recently found to inhibit mRNA translation through direct interaction with eIF4E. Here, we report the NMR assignment of this RING-containing protein that was determined by triple resonance NMR techniques.


Assuntos
Arenaviridae/química , Proteínas de Transporte/química , Espectroscopia de Ressonância Magnética/métodos , Domínios RING Finger , Proteínas da Matriz Viral/química , Sequência de Aminoácidos , Isótopos de Carbono/química , Dados de Sequência Molecular , Peso Molecular , Isótopos de Nitrogênio/química , Prótons , Proteínas de Ligação a RNA
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