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Eukaryotic Elongation Factor 2
Eukaryotic elongation factor 2 is a protein that in humans is encoded by the ''EEF2'' gene. It is the archaeal and eukaryotic counterpart of bacterial EF-G. This gene encodes a member of the GTP-binding translation elongation factor family. This protein is an essential factor for protein synthesis. It promotes the GTP-dependent translocation of the ribosome. This protein is completely inactivated by EF-2 kinase phosphorylation. aEF2/eEF2 found in most archaea and eukaryotes, including humans, contains a post translationally modified histidine diphthamide. It is the target of diphtheria toxin (from '' Corynebacterium diphtheriae''), and exotoxin A (from ''Pseudomonas aeruginosa ''Pseudomonas aeruginosa'' is a common encapsulated, gram-negative, aerobic–facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, ''P. aerug ...''). The inactivation of EF-2 by toxins inhibits prote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EF-G
EF-G (elongation factor G, historically known as translocase) is a prokaryotic elongation factor involved in protein translation. As a GTPase, EF-G catalyzes the movement (translocation) of transfer RNA (tRNA) and messenger RNA (mRNA) through the ribosome. Structure Encoded by the ''fusA'' gene on the ''str'' operon, EF-G is made up of 704 amino acids that form 5 domains, labeled Domain I through Domain V. Domain I may be referred to as the G-domain or as Domain I(G), since it binds to and hydrolyzes guanosine triphosphate (GTP). Domain I also helps EF-G bind to the ribosome, and contains the N-terminal of the polypeptide chain. Domain IV is important for translocation, as it undergoes a significant conformational change and enters the A site on the 30S ribosomal subunit, pushing the mRNA and tRNA molecules from the A site to the P site. The five domains may be also separated into two super-domains. Super-domain I consists of Domains I and II, and super-domain II consists o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guanosine Triphosphate
Guanosine-5'-triphosphate (GTP) is a purine nucleoside triphosphate. It is one of the building blocks needed for the synthesis of RNA during the transcription process. Its structure is similar to that of the guanosine nucleoside, the only difference being that nucleotides like GTP have phosphates on their ribose sugar. GTP has the guanine nucleobase attached to the 1' carbon of the ribose and it has the triphosphate moiety attached to ribose's 5' carbon. It also has the role of a source of energy or an activator of substrates in metabolic reactions, like that of ATP, but more specific. It is used as a source of energy for protein synthesis and gluconeogenesis. GTP is essential to signal transduction, in particular with G-proteins, in second-messenger mechanisms where it is converted to guanosine diphosphate (GDP) through the action of GTPases. Uses Energy transfer GTP is involved in energy transfer within the cell. For instance, a GTP molecule is generated by one of the enz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elongation Factor
Elongation factors are a set of proteins that function at the ribosome, during protein synthesis, to facilitate translational elongation from the formation of the first to the last peptide bond of a growing polypeptide. Most common elongation factors in prokaryotes are EF-Tu, EF-Ts, EF-G. Bacteria and eukaryotes use elongation factors that are largely homologous to each other, but with distinct structures and different research nomenclatures. Elongation is the most rapid step in translation. In bacteria, it proceeds at a rate of 15 to 20 amino acids added per second (about 45-60 nucleotides per second). In eukaryotes the rate is about two amino acids per second (about 6 nucleotides read per second). Elongation factors play a role in orchestrating the events of this process, and in ensuring the high accuracy translation at these speeds. Nomenclature of homologous EFs In addition to their cytoplasmic machinery, eukaryotic mitochondria and plastids have their own translation ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elongation Factor 2 Kinase
In enzymology, an elongation factor 2 kinase () is an enzyme that catalyzes the chemical reaction: :ATP + longation factor 2\rightleftharpoons ADP + longation factor 2phosphate. Thus, the two substrates of this enzyme are ATP and elongation factor 2, whereas its two products are adenosine diphosphate (ADP) and elongation factor 2 phosphate. Nomenclature This enzyme belongs to the family of transferases, specifically those transferring a phosphate group to the sidechain oxygen atom of serine or threonine residues in proteins ( protein-serine/threonine kinases). The systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature. A semisystematic name or semitrivial ... of this enzyme class is "ATP: longation factor 2phosphotransferase". Other names in common use include Ca/CaM-kinase III, calmodulin-depende ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diphthamide
Diphthamide is a post-translationally modified histidine amino acid found in archaeal and eukaryotic elongation factor 2 (eEF-2). Structure Diphthamide is proposed to be a 2- -carboxyamido-3-(trimethylammonio)propylistidine. Though this structure has been confirmed by X-ray crystallography, its stereochemistry is uncertain. Biological function Diphthamide ensures translation fidelity. The presence or absence of diphthamide is known to affect NF-κB Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a protein complex that controls transcription of DNA, cytokine production and cell survival. NF-κB is found in almost all animal cell types and is involved in cellular ... or death receptor pathways. Biosynthesis Diphthamide is biosynthesized from histidine and ''S''-adenosyl methionine. References {{Reflist Amino acids Imidazoles Quaternary ammonium compounds Post-translational modification Zwitterions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diphtheria Toxin
Diphtheria toxin is an exotoxin secreted by '' Corynebacterium diphtheriae'', the pathogenic bacterium that causes diphtheria. The toxin gene is encoded by a prophageA prophage is a virus that has inserted itself into the genome of the host bacterium. called corynephage β. The toxin causes the disease in humans by gaining entry into the cell cytoplasm and inhibiting protein synthesis. Structure Diphtheria toxin is a single polypeptide chain of 535 amino acids consisting of two subunits linked by disulfide bridges, known as an A-B toxin. Binding to the cell surface of the B subunit (the less stable of the two subunits) allows the A subunit (the more stable part of the protein) to penetrate the host cell. The crystal structure of the diphtheria toxin homodimer has been determined to 2.5 Ångstrom resolution. The structure reveals a Y-shaped molecule consisting of three domains. Fragment A contains the catalytic C domain, and fragment B consists of the T and R domains: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corynebacterium Diphtheriae
''Corynebacterium diphtheriae'' is the pathogenic bacterium that causes diphtheria. It is also known as the Klebs–Löffler bacillus, because it was discovered in 1884 by German bacteriologists Edwin Klebs (1834–1912) and Friedrich Löffler (1852–1915). The bacteria are usually harmless unless they are infected by a bacteriophage that carries a gene that gives rise to a toxin. This toxin causes the disease. Diphtheria is caused by the adhesion and infiltration of the bacteria into the mucosal layers of the body, primarily affecting the respiratory tract and the subsequent release of an endotoxin. The toxin has a localized effect on skin lesions, as well as a metastatic, proteolytic effects on other organ systems in severe infections. Originally a major cause of childhood mortality, diphtheria has been almost entirely eradicated due to the vigorous administration of the diphtheria vaccination in the 1910s. Diphtheria is no longer transmitted as frequently due to the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exotoxin A
The Pseudomonas exotoxin (or exotoxin A) is an exotoxin produced by ''Pseudomonas aeruginosa''. ''Vibrio cholerae'' produces a similar protein called the Cholix toxin (). It inhibits elongation factor-2. It does so by ADP-ribosylation of EF2 using NAD+. This then causes the elongation of polypeptides to cease. This mechanism is similar to that of diphtheria toxin. It has been investigated as a treatment for 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. Fo ... and cancer. References External links *P11439 (eta)in InterPro domain view {{Toxins Bacterial toxins Proteins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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