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Matrix Protein
Viral matrix proteins are structural proteins linking the viral envelope with the virus core. They play a crucial role in virus assembly, and interact with the RNP complex as well as with the viral membrane. They are found in many enveloped viruses including paramyxoviruses, orthomyxoviruses, herpesviruses, retroviruses, filoviruses and other groups. An example is the M1 protein of the influenza virus, showing affinity to the glycoproteins inserted in the host cell membrane on one side and affinity for the RNP complex molecules on the other side, which allows formation at the membrane of a complex made of the viral ribonucleoprotein at the inner side indirectly connected to the viral glycoproteins protruding from the membrane. This assembly complex will now bud In botany, a bud is an undeveloped or Plant embryogenesis, embryonic Shoot (botany), shoot and normally occurs in the axil of a leaf or at the tip of a Plant stem, stem. Once formed, a bud may remain for some ti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paramyxoviridae
''Paramyxoviridae'' (from Ancient Greek, Greek ''para-'' “by the side of” and ''myxa'' “mucus”) is a family of negative-strand RNA viruses in the order ''Mononegavirales''. Vertebrates serve as natural hosts. Diseases associated with this family include measles, mumps, and respiratory tract infections. The family has nine subfamilies that contain 23 genera. Structure Virions are enveloped and can be spherical or pleomorphic and capable of producing filamentous virions. The diameter is around 150 nm. Genomes are linear, around 15kb in length. Fusion proteins and attachment proteins appear as spikes on the virion surface. Matrix proteins inside the envelope stabilise virus structure. The nucleocapsid core is composed of the genomic RNA, nucleocapsid proteins, phosphoproteins and polymerase proteins. Genome The genome is non-segmented, negative-sense RNA, 15–19 kilobases in length, and contains six to 10 genes. Extracistronic (noncoding) regions include: * A 3’ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Influenza
Influenza, commonly known as the flu, is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptoms begin one to four (typically two) days after exposure to the virus and last for about two to eight days. Diarrhea and vomiting can occur, particularly in children. Influenza may progress to pneumonia from the virus or a subsequent bacterial infection. Other complications include acute respiratory distress syndrome, meningitis, encephalitis, and worsening of pre-existing health problems such as asthma and cardiovascular disease. There are four types of influenza virus: types A, B, C, and D. Aquatic birds are the primary source of influenza A virus (IAV), which is also widespread in various mammals, including humans and pigs. Influenza B virus (IBV) and influenza C virus (ICV) primarily infect humans, and influenza D virus (IDV) i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viral Tegument
A viral tegument or tegument, more commonly known as a viral matrix, is a cluster of proteins that lines the space between the envelope and nucleocapsid of all herpesviruses. The tegument generally contains proteins that aid in viral DNA replication and evasion of the immune response, typically with inhibition of signalling in the immune system and activation of interferons. The tegument is usually released shortly after infection into the cytoplasm. These proteins are usually formed within the late phase of the viral infectious cycle, after viral genes have been replicated. Much information regarding viral teguments has been gathered from studying herpes simplex virus. Properties of teguments Viral teguments can be symmetrically arranged via structural and scaffolding protein or can also be asymmetrically arranged, depending on the virus. Teguments are rarely haphazardly placed and usually involve scaffolding proteins in their formation around the nucleocapsid. Non-essentia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retroviral Matrix Protein
Retroviral matrix proteins are components of Viral envelope, envelope-associated capsids of retroviruses. These proteins line the inner surface of viral envelopes and are associated with viral membranes. Matrix proteins are produced as N-terminal protein domain, domains of Gag Protein precursor, precursor polyproteins. The Gag polyprotein directs the assembly and release of virus particles from infected cells. The Gag polyprotein has three domains required for activity: an N-terminal membrane-binding (M) domain (which corresponds to the matrix protein) that directs Gag to the plasma membrane, an interaction (I) domain involved in Gag aggregation, and a late assembly (L) domain that mediates the viral budding, budding process . During viral maturation, the Gag polyprotein is cleaved by the retroviral protease into several corresponding structural proteins, yielding the matrix (MA), p24 capsid protein, capsid (CA), and nucleocapsid (NC) proteins, and some smaller peptides. Gag-derived ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viral Tegument
A viral tegument or tegument, more commonly known as a viral matrix, is a cluster of proteins that lines the space between the envelope and nucleocapsid of all herpesviruses. The tegument generally contains proteins that aid in viral DNA replication and evasion of the immune response, typically with inhibition of signalling in the immune system and activation of interferons. The tegument is usually released shortly after infection into the cytoplasm. These proteins are usually formed within the late phase of the viral infectious cycle, after viral genes have been replicated. Much information regarding viral teguments has been gathered from studying herpes simplex virus. Properties of teguments Viral teguments can be symmetrically arranged via structural and scaffolding protein or can also be asymmetrically arranged, depending on the virus. Teguments are rarely haphazardly placed and usually involve scaffolding proteins in their formation around the nucleocapsid. Non-essentia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhabdoviridae
''Rhabdoviridae'' is a family of negative-strand RNA viruses in the order ''Mononegavirales''. Vertebrates (including mammals and humans), invertebrates, plants, fungi and protozoans serve as natural hosts. Diseases associated with member viruses include Rabies, rabies encephalitis caused by the rabies virus, and flu-like symptoms in humans caused by vesiculoviruses. The name is derived from Ancient Greek , meaning rod, referring to the shape of the viral particles. The family has 62 genera, most assigned to four subfamilies. Structure The individual virus particles (virions) of rhabdoviruses are composed of RNA, protein, carbohydrate and lipid. They have complex bacilliform or bullet-like shapes. All these viruses have structural similarities and have been classified as a single family. The virions are about 75 nm wide and 180 nm long. Rhabdoviruses are Viral envelope, enveloped and have helical Capsid, nucleocapsids and their genomes are linear, around 11–15 kb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Budding
Budding or blastogenesis is a type of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. For example, the small bulb-like projection coming out from the yeast cell is known as a bud. Since the reproduction is asexual, the newly created organism is a clone and, excepting mutations, is genetically identical to the parent organism. Organisms such as hydra use regenerative cells for reproduction in the process of budding. In hydra, a bud develops as an outgrowth due to repeated cell division of the parent body at one specific site. These buds develop into tiny individuals and, when fully mature, detach from the parent body and become new independent individuals. Internal budding or endodyogeny is a process of asexual reproduction, favored by parasites such as '' Toxoplasma gondii''. It involves an unusual process in which two daughter cells are produced inside a mother cell, which is then consumed by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribonucleoprotein
Nucleoproteins are proteins conjugated with nucleic acids (either DNA or RNA). Typical nucleoproteins include ribosomes, nucleosomes and viral nucleocapsid proteins. Structures Nucleoproteins tend to be positively charged, facilitating interaction with the negatively charged nucleic acid chains. The Protein tertiary structure, tertiary structures and biological functions of many nucleoproteins are understood.Graeme K. Hunter G. K. (2000): Vital Forces. The discovery of the molecular basis of life. Academic Press, London 2000, . Important techniques for determining the structures of nucleoproteins include X-ray diffraction, nuclear magnetic resonance and cryo-electron microscopy. Viruses Virus genomes (either DNA virus, DNA or RNA virus, RNA) are extremely tightly packed into the Capsid, viral capsid. Many viruses are therefore little more than an organised collection of nucleoproteins with their binding sites pointing inwards. Structurally characterised viral nucleoproteins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycoprotein
Glycoproteins are proteins which contain oligosaccharide (sugar) chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. Secreted extracellular proteins are often glycosylated. In proteins that have segments extending extracellularly, the extracellular segments are also often glycosylated. Glycoproteins are also often important integral membrane proteins, where they play a role in cell–cell interactions. It is important to distinguish endoplasmic reticulum-based glycosylation of the secretory system from reversible cytosolic-nuclear glycosylation. Glycoproteins of the cytosol and nucleus can be modified through the reversible addition of a single GlcNAc residue that is considered reciprocal to phosphorylation and the functions of these are likely to be an additional regulatory mechanism that controls phosphorylation-based signalling. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M1 Protein
The M1 protein is a matrix protein of the influenza virus. It forms a coat inside the viral envelope. This is a bifunctional membrane/RNA-binding protein that mediates the encapsidation of nucleoprotein cores into the membrane envelope. It is therefore required that M1 binds both membrane and RNA simultaneously. The M1 protein binds to the viral RNA. The binding is not specific to any RNA sequence, and is performed via a peptide sequence rich in basic amino acids. It also has multiple regulatory functions, performed by interaction with the components of the host cell. The mechanisms regulated include a role in the export of the viral ribonucleoproteins from the host cell nucleus, inhibition of viral transcription, and a role in the virus assembly and budding. The protein was found to undergo phosphorylation in the host cell. The M1 protein forms a layer under the patches of host cell membrane that are rich with the viral hemagglutinin, neuraminidase and M2 transmembrane prot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pneumoviridae
''Pneumoviridae'' (from Greek ''pneumo-'' 'lung' + ''-viridae'' 'virus', from Latin, 'poison, slimy liquid') is a family of Negative-strand RNA virus, negative-strand RNA viruses in the order ''Mononegavirales''. Humans, cattle, and rodents serve as natural hosts. Respiratory tract infection, Respiratory tract infections are associated with member viruses such as human respiratory syncytial virus. There are five species in the family which are divided between the genera ''Metapneumovirus'' and ''Orthopneumovirus''. The family used to be considered as a sub-family of ''Paramyxoviridae'', but has been reclassified as of 2016. Virology Structure Pneumoviruses are pleomorphic, capable of producing spherical and filamentous, Viral envelope, enveloped virions (virus particles) that vary in size from 150 to 200 nm in diameter. The nucleocapsid consisting of a protein shell and viral nucleic acids has a helical symmetry. Nucleocapsids have a diameter of 13.5 nm and a helica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filoviridae
''Filoviridae'' () is a International Committee on Taxonomy of Viruses, family of RNA virus#Group_V_–_negative-sense_ssRNA_viruses, single-stranded negative-sense RNA viruses in the order (biology), order ''Mononegavirales''. Two members of the family that are commonly known are Zaire ebolavirus, Ebola virus and Marburg virus. Both viruses, and some of their lesser known relatives, cause severe disease in humans and nonhuman primates in the form of viral hemorrhagic fevers. All filoviruses are classified by the US as select agents, by the World Health Organization as Risk Group 4 Pathogens (requiring Biosafety, Biosafety Level 4-equivalent containment), by the National Institutes of Health/National Institute of Allergy and Infectious Diseases as Category A Priority Pathogens, and by the Centers for Disease Control and Prevention as Bioterrorism, Category A Bioterrorism Agents, and are listed as Biological Agents for Export Control by the Australia Group. Use of term The Interna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
