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Viral Nonstructural Proteins
In virology, a nonstructural protein is a protein encoded by a virus but that is not part of the viral particle. They typically include the various enzymes and transcription factors the virus uses to replicate itself, such as a viral protease ( 3CL/nsp5, etc.), an RNA replicase or other template-directed polymerases, and some means to control the host. Examples * NSP1 (rotavirus) * NSP4 (rotavirus) * NSP5 (rotavirus) * Influenza non-structural protein * NS1 influenza protein * HBcAg, core antigen of hepatitis B *Bunyaviridae nonstructural S proteins See also * Viral structural protein A viral structural protein is a viral protein that is a structural component of the mature virus. Examples include the SARS coronavirus 3a and 7a accessory proteins. Bacteriophage T4 structural proteins During assembly of the bacteriophage (pha ... References {{protein-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virology
Virology is the Scientific method, scientific study of biological viruses. It is a subfield of microbiology that focuses on their detection, structure, classification and evolution, their methods of infection and exploitation of host (biology), host cell (biology), cells for reproduction, their interaction with host organism physiology and immunity, the diseases they cause, the techniques to isolate and culture them, and their use in research and therapy. The identification of the causative agent of tobacco mosaic disease (TMV) as a novel pathogen by Martinus Beijerinck (1898) is now acknowledged as being the history of virology, official beginning of the field of virology as a discipline distinct from bacteriology. He realized the source was neither a bacterial nor a fungal infection, but something completely different. Beijerinck used the word "virus" to describe the mysterious agent in his 'contagium vivum fluidum' ('contagious living fluid'). Rosalind Franklin proposed the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NSP4 (rotavirus)
The rotavirus nonstructural protein NSP4 was the first viral enterotoxin discovered. It is a viroporin and induces diarrhea and causes Ca2+-dependent transepithelial secretion. A transmembrane glycoprotein, NSP4 is organized into three main domains: a three-helical TM domain in the N-terminus (also a viroporin domain), a central cytoplasmic coiled-coil domain for multimerization, and an C-terminal flexible region. It can also be secreted out of the cell. As of 2019, only structures of the central domain, which is responsible for diarrhea, has been solved. It oligomerizes into dimeric, tetrameric, pentameric A pentamer is an entity composed of five sub-units. In chemistry, it applies to molecules made of five monomers. In biochemistry, it applies to macromolecules, in particular to pentameric proteins, made of five proteic sub-units. In microbiolog ..., and even higher-order forms. References Rotaviruses Viral nonstructural proteins {{enzyme-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bunyaviridae Nonstructural S Proteins
''Bunyaviridae'' nonstructural S proteins (NSs) are synthesized by viral DNA/RNA and do not play a role in the replication or the viral protein coating. The nonstructural S segment (NSs) created by ''Bunyaviridae'' virus family'','' are able to interact with the human immune system, in order to increase their replication in infected cells. Understanding this mechanism can have global health impacts. Inhibition Pathways Within the ''Bunyaviridae'' virus family, specifically ''phlebovirus'' genus, there has been multiple pathways of the inhibition of the immune response. NSs proteins are able to interact with interferon (INF) pathways, but the mechanism varies from virus to virus. The NSs protein in different viruses have been shown to differ in amino acid sequence by up to 85%. Rift Valley Fever Virus In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear dow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hepatitis B
Hepatitis B is an infectious disease caused by the ''Hepatitis B virus'' (HBV) that affects the liver; it is a type of viral hepatitis. It can cause both acute and chronic infection. Many people have no symptoms during an initial infection. For others, symptoms may appear 30 to 180 days after becoming infected and can include a rapid onset of sickness with nausea, vomiting, yellowish skin, fatigue, dark urine, and abdominal pain. Symptoms during acute infection typically last for a few weeks, though some people may feel sick for up to six months. Deaths resulting from acute stage HBV infections are rare. An HBV infection lasting longer than six months is usually considered chronic. The likelihood of developing chronic hepatitis B is higher for those who are infected with HBV at a younger age. About 90% of those infected during or shortly after birth develop chronic hepatitis B, while less than 10% of those infected after the age of five develop chronic cases. Most of those wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HBcAg
HBcAg (core antigen) is a hepatitis B viral protein. It is an indicator of active viral replication; this means the person infected with Hepatitis B can likely transmit the virus on to another person (i.e. the person is infectious). Structure and function HBcAg is an antigen that can be found on the surface of the nucleocapsid core (the inner most layer of the hepatitis B virus). While both HBcAg and HBeAg are made from the same open reading frame, HBcAg is not secreted. HBcAg is considered "particulate" and it does not circulate in the blood but recent study show it can be detected in serum by Radioimmunoassay. However, it is readily detected in hepatocytes after biopsy. The presence of both HBcAg and HBeAg proteins together act as a marker of viral replication, and antibodies to these antigens are a marker of declining replication. Interactions Tapasin can interact with HBcAg18-27 and enhance cytotoxic T-lymphocyte response against HBV. See also *HBeAg *HBsAg HBsAg (a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NS1 Influenza Protein
The NS1 influenza protein (NS1) is a viral nonstructural protein encoded by the NS gene segments of type Influenza A virus, A, Influenza B, B and Influenza C virus, C influenza viruses. Also encoded by this segment is the nuclear export protein (NEP), formally referred to as NS2 (HCV), NS2 protein, which mediates the export of influenza virus ribonucleoprotein (RNP) complexes from the nucleus, where they are assembled.Influenza B and C Virus NEP (NS2) Proteins Possess Nuclear Export Activities Journal of Virology, August 2001, p. 7375-7383, Vol. 75, No. 16 Characteristics The NS1 of influenza A virus is a 26,000 Dalton protein. It prevents polyadenylation of cellular mRNAs to circumvent antiviral responses of the host, e ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Influenza Non-structural Protein
Influenza non-structural protein (NS1) is a homodimeric RNA-binding protein found in influenza virus that is required for viral replication. NS1 binds polyA tails of mRNA keeping them in the nucleus. NS1 inhibits pre-mRNA splicing by tightly binding to a specific stem-bulge of U6 snRNA U6 snRNA is the non-coding small nuclear RNA (snRNA) component of U6 snRNP (''small nuclear ribonucleoprotein''), an RNA-protein complex that combines with other snRNPs, unmodified pre-mRNA, and various other proteins to assemble a spliceosome, a .... References {{DEFAULTSORT:Influenza Non-Structural Protein Protein families ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NSP5 (rotavirus)
NSP5 ( nonstructural protein 5) encoded by genome segment 11 of group A rotaviruses. In virus-infected cells NSP5 accumulates in the viroplasms. NSP5 has been shown to be autophosphorylated. Interaction of NSP5 with NSP2 was also demonstrated. In rotavirus-infected cells, the non-structural proteins NSP5 and NSP2 localize in complexes called viroplasms, where replication and assembly occur and they can drive the formation of viroplasm-like structures in the absence of other rotaviral proteins and rotavirus replication. There is no atomic-resolution structure of NSP5 determined as of June 2019. However, the low resolution three-dimensional structure of the NSP2-NSP5 assembly has been observed by cryo-EM Cryogenic electron microscopy (cryo-EM) is a cryomicroscopy technique applied on samples cooled to cryogenic temperatures. For biological specimens, the structure is preserved by embedding in an environment of vitreous ice. An aqueous sample sol .... NSP5 occupies the same site ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NSP1 (rotavirus)
NSP1 (NS53), the product of rotavirus gene 5, is a nonstructural RNA-binding protein that contains a cysteine-rich region and is a component of early replication intermediates. RNA-folding predictions suggest that this region of the NSP1 mRNA can interact with itself, producing a stem-loop structure similar to that found near the 5'-terminus of the NSP1 mRNA. The carboxyl-half of the rotavirus nonstructural protein NSP1 is not required for virus replication. NSP1 could play a role in host range restriction. The cysteine-rich region of NSP1 is not considered essential for genome segment reassortment with heterologous virus. NSP1 interacts with IRF3 in the infected cell. NSP1 is an antagonist of the IFN-signaling pathway. Interferon regulatory factor 3 (IRF3) is a key transcription factor involved in the induction of interferon (IFN) in response to viral infection. NSP1 binds to and targets IRF3 for proteasome degradation early post-infection. IRF3 degradation is dependent on th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viral Protein
A viral protein is both a component and a product of a virus. Viral proteins are grouped according to their functions, and groups of viral proteins include structural proteins, nonstructural proteins, regulatory proteins, and accessory proteins. Viruses are non-living and do not have the means to reproduce on their own, instead depending on their host cell's resources in order to reproduce. Thus, viruses do not code for many of their own viral proteins, and instead use the host cell's machinery to produce the viral proteins they require for replication. Viral structural proteins Most viral structural proteins are components for the capsid and the envelope of the virus. Capsid The genetic material of a virus is stored within a viral protein structure called the capsid. The capsid is a "shield" that protects the viral nucleic acids from getting degraded by host enzymes or other types of pesticides or pestilences. It also functions to attach the virion to its host, and enable the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNA Replicase
RNA-dependent RNA polymerase (RdRp) or RNA replicase is an enzyme that catalyzes the replication of RNA from an RNA template. Specifically, it catalyzes synthesis of the RNA strand complementary to a given RNA template. This is in contrast to typical DNA-dependent RNA polymerases, which all organisms use to catalyze the transcription of RNA from a DNA template. RdRp is an essential protein encoded in the genomes of most RNA-containing viruses with no DNA stage including SARS-CoV-2. Some eukaryotes also contain RdRps, which are involved in RNA interference and differ structurally from viral RdRps. History Viral RdRps were discovered in the early 1960s from studies on mengovirus and polio virus when it was observed that these viruses were not sensitive to actinomycin D, a drug that inhibits cellular DNA-directed RNA synthesis. This lack of sensitivity suggested that there is a virus-specific enzyme that could copy RNA from an RNA template and not from a DNA template. Distr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C30 Endopeptidase
The 3C-like protease (3CLpro) or main protease (Mpro), formally known as C30 endopeptidase or 3-chymotrypsin-like protease, is the main protease found in coronaviruses. It cleaves the coronavirus polyprotein at eleven conserved sites. It is a cysteine protease and a member of the PA clan of proteases. It has a cysteine-histidine catalytic dyad at its active site and cleaves a Gln–(Ser/Ala/Gly) peptide bond. The Enzyme Commission refers to this family as SARS coronavirus main proteinase (Mpro; ). The 3CL protease corresponds to coronavirus nonstructural protein 5 (nsp5). The "3C" in the common name refers to the 3C protease (3Cpro) which is a homologous protease found in picornaviruses. Function The 3C-like protease is able to catalytically cleave a peptide bond between a glutamine at position P1 and a small amino acid (serine, alanine, or glycine) at position P1'. The SARS coronavirus 3CLpro can for instance self-cleave the following peptides: The protease is impor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
