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Coronavirus Packaging Signal
The Coronavirus packaging signal is a conserved cis-regulatory element found in Betacoronavirus (part of the Coronavirus subfamily of viruses). It has an important role in regulating the packaging of the viral genome into the capsid. As part of the viral life cycle, within the infected cell, the viral genome becomes associated with viral proteins and assembles into new infective progeny viruses. This process is called packaging and is vital for viral replication. The packaging signal is found in the positive-sense single-stranded RNA genome. It interacts with the viral proteins ( M and N) and ensures the selective packaging of viral RNA into virions. This RNA element is conserved in Embecovirus (previously known as lineage A Betacoronavirus), which includes mouse hepatitis virus (MHV), bovine coronavirus (BCoV), and human coronaviruses like HCoV-HKU1 and HCoV-OC43. Notably, this element is absent from the other viral lineages which have evolved separate packaging signals. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Structure
Protein secondary structure is the three dimensional conformational isomerism, form of ''local segments'' of proteins. The two most common Protein structure#Secondary structure, secondary structural elements are alpha helix, alpha helices and beta sheets, though beta turns and omega loops occur as well. Secondary structure elements typically spontaneously form as an intermediate before the protein protein folding, folds into its three dimensional protein tertiary structure, tertiary structure. Secondary structure is formally defined by the pattern of hydrogen bonds between the Amine, amino hydrogen and carboxyl oxygen atoms in the peptide backbone chain, backbone. Secondary structure may alternatively be defined based on the regular pattern of backbone Dihedral angle#Dihedral angles of proteins, dihedral angles in a particular region of the Ramachandran plot regardless of whether it has the correct hydrogen bonds. The concept of secondary structure was first introduced by Kaj Ulrik ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bovine Coronavirus
Bovine coronavirus (BCV or BCoV) is a coronavirus which is a member of the species ''Betacoronavirus 1''. The infecting virus is an enveloped, positive-sense, single-stranded RNA virus which enters its host cell by binding to the N-acetyl-9-O-acetylneuraminic acid recepter. Infection causes calf enteritis and contributes to the enzootic pneumonia complex in calves. It can also cause winter dysentery in adult cattle. It can infect both domestic and wild ruminants and has a worldwide distribution. Transmission is horizontal, via oro-fecal or respiratory routes. Like other coronaviruses from genus ''Betacoronavirus,'' subgenus ''Embecovirus'', it has a surface protein called hemagglutinin esterase (HE) in addition to the four structural proteins shared by all coronaviruses (spike, membrane, nucleocapsid, and envelope proteins). Virology BCoV has 95% similarity with human coronavirus OC43 and 93% to porcine hemagglutinating encephalomyelitis virus. According to a 2006 study, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coronavirus 3′ UTR Pseudoknot
The Coronavirus 3′ UTR pseudoknot is an RNA structure found in the coronavirus genome. Coronaviruses contain 30 kb single-stranded positive-sense RNA genomes. The 3′ UTR region of these coronavirus genomes contains a conserved ~55 nucleotide pseudoknot structure which is necessary for viral genome replication. The mechanism of cis-regulation is unclear, but this element is postulated to function in the plus-strand. Other RNA families identified in the coronavirus include the coronavirus frameshifting stimulation element, the coronavirus 3′ stem-loop II-like motif (s2m) The Coronavirus 3′ stem-loop II-like motif (also known as s2m) is a secondary structure motif identified in the 3′ UTR, 3′ untranslated region (3′UTR) of astrovirus, coronavirus and equine rhinovirus genomes. Its function is unknown, but ... and the coronavirus packaging signal. References External links * Cis-regulatory RNA elements Coronaviridae {{molecular-cell-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coronavirus 3′ UTR
Coronavirus genomes are positive-sense single-stranded RNA molecules with an untranslated region (UTR) at the 3′ end which is called the 3′ UTR. The 3′ UTR is responsible for important biological functions, such as viral replication. The 3′ UTR has a conserved RNA secondary structure but different Coronavirus genera ( Alpha-, Beta-, Gamma-, and Deltacoronaviruses) have different structural features described below. Alphacoronavirus 3′ UTR The 3′ UTR of Alphacoronaviruses consists of two small hairpins (PK-SL2) which can form an alternate conformation (PK-SL1) where the loop region of the second hairpin interacts with the stem of the first hairpin (see Coronavirus 3′ UTR pseudoknot). PK-SL2 has been confirmed in HCoV-229E and HCoV-NL63 by in vitro structure probing experiments. Downstream of this pseudoknot lies the hypervariable region (HVR), which is supported by many covarying base pairs in alphacoronaviruses. Further, a conserved octanucleotide sequence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coronavirus 5′ UTR
Coronavirus genomes are positive-sense single-stranded RNA molecules with an untranslated region (UTR) at the 5′ end which is called the 5′ UTR. The 5′ UTR is responsible for important biological functions, such as viral replication, transcription and packaging. The 5′ UTR has a conserved RNA secondary structure but different Coronavirus genera ( Alpha-, Beta-, Gamma-, and Deltacoronaviruses) have different structural features described below. Alphacoronavirus 5′ UTR The first 150 to 200 nucleotides within the 5′ UTR of Alphacoronaviruses are highly structured and shown to be conserved on the structural level. The 5′ UTRs are predicted to contain three conserved stem-loops: * SL1 is important for viral replication, most likely playing a role in the template-switch of viral subgenomic RNA (sgRNA) transcription. Mutations of the upper part of SL1 seem to have a higher impact of viral replication level. * SL2 is crucial for viral viability. Nucleotides are in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coronavirus 3′ UTR Pseudoknot
The Coronavirus 3′ UTR pseudoknot is an RNA structure found in the coronavirus genome. Coronaviruses contain 30 kb single-stranded positive-sense RNA genomes. The 3′ UTR region of these coronavirus genomes contains a conserved ~55 nucleotide pseudoknot structure which is necessary for viral genome replication. The mechanism of cis-regulation is unclear, but this element is postulated to function in the plus-strand. Other RNA families identified in the coronavirus include the coronavirus frameshifting stimulation element, the coronavirus 3′ stem-loop II-like motif (s2m) The Coronavirus 3′ stem-loop II-like motif (also known as s2m) is a secondary structure motif identified in the 3′ UTR, 3′ untranslated region (3′UTR) of astrovirus, coronavirus and equine rhinovirus genomes. Its function is unknown, but ... and the coronavirus packaging signal. References External links * Cis-regulatory RNA elements Coronaviridae {{molecular-cell-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coronavirus 3′ Stem-loop II-like Motif (s2m)
The Coronavirus 3′ stem-loop II-like motif (also known as s2m) is a secondary structure motif identified in the 3′ UTR, 3′ untranslated region (3′UTR) of astrovirus, coronavirus and equine rhinovirus genomes. Its function is unknown, but various viral 3′ UTR regions have been found to play roles in viral replication and packaging. This motif appears to be conserved in both nucleotide sequence and secondary structure folding indicating a strong evolutionary selection for its Conserved sequence, conservation. The presence of this conserved motif in different viral families is suggested to be the result of at least two separate Genetic recombination, recombination events. To date s2m has been described in four families of positive sense single-stranded RNA viruses; ''Astrovirus, Astroviridae'', ''Caliciviridae'', ''Picornavirus, Picornaviridae'' and ''Coronavirus, Coronaviridae''. The viruses that contain s2m can infect a wide range of higher vertebrates, including birds, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coronavirus Frameshifting Stimulation Element
In molecular biology, the coronavirus frameshifting stimulation element is a conserved stem-loop of RNA found in coronaviruses that can promote ribosomal frameshifting. Such RNA molecules interact with a downstream region to form a pseudoknot structure; the region varies according to the virus but pseudoknot formation is known to stimulate frameshifting. In the classical situation, a sequence 32 nucleotides downstream of the stem is complementary to part of the loop. In other coronaviruses, however, another stem-loop structure around 150 nucleotides downstream can interact with members of this family to form kissing stem-loops and stimulate frameshifting. Other RNA families identified in the coronavirus include the coronavirus 3′ stem-loop II-like motif (s2m), the coronavirus packaging signal and the coronavirus 3′ UTR pseudoknot. During protein synthesis, rapidly changing conditions in the cell can cause ribosomal pausing. In coronaviruses, this can affect growth rate an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peptide
Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. A polypeptide is a longer, continuous, unbranched peptide chain. Hence, peptides fall under the broad chemical classes of biological polymers and oligomers, alongside nucleic acids, oligosaccharides, polysaccharides, and others. A polypeptide that contains more than approximately 50 amino acids is known as a protein. Proteins consist of one or more polypeptides arranged in a biologically functional way, often bound to ligands such as coenzymes and cofactors, or to another protein or other macromolecule such as DNA or RNA, or to complex macromolecular assemblies. Amino acids that have been incorporated into peptides are termed residues. A water molecule is released during formation of each amide bond.. All peptides except cyclic pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viral Nonstructural Protein
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] |
Nucleic Acid Secondary Structure
Nucleic acid secondary structure is the basepairing interactions within a single nucleic acid polymer or between two polymers. It can be represented as a list of bases which are paired in a nucleic acid molecule. The secondary structures of biological DNAs and RNAs tend to be different: biological DNA mostly exists as fully base paired double helices, while biological RNA is single stranded and often forms complex and intricate base-pairing interactions due to its increased ability to form hydrogen bonds stemming from the extra hydroxyl group in the ribose sugar. In a non-biological context, secondary structure is a vital consideration in the nucleic acid design of nucleic acid structures for DNA nanotechnology and DNA computing, since the pattern of basepairing ultimately determines the overall structure of the molecules. Fundamental concepts Base pairing In molecular biology, two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Severe Acute Respiratory Syndrome Coronavirus 2
Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) is a strain of coronavirus that causes COVID-19 (coronavirus disease 2019), the respiratory illness responsible for the ongoing COVID-19 pandemic. The virus previously had a Novel coronavirus, provisional name, 2019 novel coronavirus (2019-nCoV), and has also been called the human coronavirus 2019 (HCoV-19 or hCoV-19). First identified in the city of Wuhan, Hubei, China, the World Health Organization declared the outbreak a public health emergency of international concern on January 30, 2020, and a pandemic on March 11, 2020. SARS‑CoV‑2 is a positive-sense single-stranded RNA virus that is Contagious disease, contagious in humans. SARS‑CoV‑2 is a virus of the species ''severe acute respiratory syndrome–related coronavirus'' (SARSr-CoV), related to the Severe acute respiratory syndrome coronavirus 1, SARS-CoV-1 virus that caused the 2002–2004 SARS outbreak. Despite its close relation to SARS-CoV-1, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
