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Aminoacyl TRNA Synthetases, Class II
Aminoacyl-tRNA synthetases, class II is a family of proteins. These proteins catalyse the attachment of an amino acid to its cognate transfer RNA molecule in a highly specific two-step reaction. These proteins differ widely in size and oligomeric state, and have a limited sequence homology. The 20 aminoacyl-tRNA synthetases are divided into two classes, I and II. Class I aminoacyl-tRNA synthetases contain a characteristic Rossman fold catalytic domain and are mostly monomeric. Class II aminoacyl-tRNA synthetases share an anti-parallel beta-sheet fold flanked by alpha-helices, and are mostly dimeric or multimeric, containing at least three conserved regions. However, tRNA binding involves an alpha-helical structure that is conserved between class I and class II synthetases. In reactions catalysed by the class I aminoacyl-tRNA synthetases, the aminoacyl group is coupled to the 2'-hydroxyl of the tRNA, while, in class II reactions, the 3'-hydroxyl site is preferred. The synthetases ... [...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] |
Catalyse
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. Catalysis may be classified as either homogeneous, whose components are dispersed in the same phase (usually gaseous or liquid) as the reactant, or heterogeneous, whose components are not in the same phase. Enzymes and other biocatalysts are often considered as a third category. Catalysis is ubiquitous in chemical industry of all kinds. Estimates are that 90% of all commercially produced chemical products involve catalysts at some stag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amino Acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha amino acids appear in the genetic code. Amino acids can be classified according to the locations of the core structural functional groups, as Alpha and beta carbon, alpha- , beta- , gamma- or delta- amino acids; other categories relate to Chemical polarity, polarity, ionization, and side chain group type (aliphatic, Open-chain compound, acyclic, aromatic, containing hydroxyl or sulfur, etc.). In the form of proteins, amino acid '' residues'' form the second-largest component (water being the largest) of human muscles and other tissues. Beyond their role as residues in proteins, amino acids participate in a number of processes such as neurotransmitter transport and biosynthesis. It is thought that they played a key role in enabling life ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transfer RNA
Transfer RNA (abbreviated tRNA and formerly referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes), that serves as the physical link between the mRNA and the amino acid sequence of proteins. tRNAs genes from Bacteria are typically shorter (mean = 77.6 bp) than tRNAs from Archaea (mean = 83.1 bp) and eukaryotes (mean = 84.7 bp). The mature tRNA follows an opposite pattern with tRNAs from Bacteria being usually longer (median = 77.6 nt) than tRNAs from Archaea (median = 76.8 nt), with eukaryotes exhibiting the shortest mature tRNAs (median = 74.5 nt). Transfer RNA (tRNA) does this by carrying an amino acid to the protein synthesizing machinery of a cell called the ribosome. Complementation of a 3-nucleotide codon in a messenger RNA (mRNA) by a 3-nucleotide anticodon of the tRNA results in protein synthesis based on the mRNA code. As such, tRNAs are a necessary component of translation, the biological sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequence Homology
Sequence homology is the biological homology between DNA, RNA, or protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a speciation event (orthologs), or a duplication event (paralogs), or else a horizontal (or lateral) gene transfer event (xenologs). Homology among DNA, RNA, or proteins is typically inferred from their nucleotide or amino acid sequence similarity. Significant similarity is strong evidence that two sequences are related by evolutionary changes from a common ancestral sequence. Alignments of multiple sequences are used to indicate which regions of each sequence are homologous. Identity, similarity, and conservation The term "percent homology" is often used to mean "sequence similarity”, that is the percentage of identical residues (''percent identity''), or the percentage of residues conserved with similar physicochemical properties (' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aminoacyl TRNA Synthetases, Class I
The aminoacyl-tRNA synthetases catalyse the attachment of an amino acid to its cognate transfer RNA molecule in a highly specific two-step reaction. These proteins differ widely in size and oligomeric state, and have limited sequence homology. The 20 aminoacyl-tRNA synthetases are divided into two classes, I and II. Class I aminoacyl-tRNA synthetases contain a characteristic Rossmann fold catalytic domain and are mostly monomeric. Aminoacyl tRNA synthetases, class II, Class II aminoacyl-tRNA synthetases share an anti-parallel beta-sheet fold flanked by alpha-helices, and are mostly dimeric or multimeric, containing at least three conserved regions. However, tRNA binding involves an alpha-helical structure that is conserved between class I and class II synthetases. In reactions catalysed by the class I aminoacyl-tRNA synthetases, the aminoacyl group is coupled to the 2'-hydroxyl of the tRNA, while, in class II reactions, the 3'-hydroxyl site is preferred. The synthetases specific for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DARS (gene)
Aspartyl-tRNA synthetase, cytoplasmic is an enzyme that in humans is encoded by the ''DARS'' gene. Aspartyl-tRNA synthetase (DARS) is part of a multienzyme complex of aminoacyl-tRNA synthetases. Aspartyl-tRNA synthetase charges its cognate tRNA with aspartate during protein biosynthesis. Clinical significance Mutations in DARS have been identified as the cause of leukoencephalopathy Leukoencephalopathy (leukodystrophy-like diseases) is a term that describes all of the brain white matter diseases, whether their molecular cause is known or unknown. It can refer specifically to any of these diseases: * Progressive multifocal leuk ..., hypomyelination with brain stem and spinal cord involvement and leg spasticity (HBSL). See also * Aspartate-tRNA ligase References Further reading * * * * * * * * * * * * * * * * {{gene-2-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DARS2
DARS may refer to: * DARS (gene), a human gene * DARS (radar) Deployable Air operations centre, Recognized air picture production centre, Sensor Fusion Post, a NATO mobile deployable Command & Control radar system * DoD Architecture Registry System * Texas Department of Assistive and Rehabilitative Services, a state agency that works with Texans with disabilities and children with developmental delays * Digital Audio Radio Service, any type of digital radio service including Satellite DARS used by Sirius XM Radio * Digital Audio Reference Signal, an AES standard for synchronizing devices * Motorway Company in the Republic of Slovenia (Slovene: Družba za avtoceste v Republiki Sloveniji, DARS) * DARS caste living in District Tharparkar and Umerkot * Dars, a brand of chocolate bars produced in Japan by Morinaga & Company * DnaA-reactivating sequences (DARS) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KARS (gene)
Lysyl-tRNA synthetase is an enzyme that in humans is encoded by the ''KARS'' gene. Function Aminoacyl-tRNA synthetases are a class of enzymes that charge tRNAs with their cognate amino acids. Lysyl-tRNA synthetase is a homodimer localized to the cytoplasm which belongs to the class II family of tRNA synthetases. It has been shown to be a target of autoantibodies in the human autoimmune diseases, polymyositis or dermatomyositis Besides its role in translation, Lysyl-tRNA synthetase is involved in a signaling pathway leading to gene activation. Following physiological stimulation of a variety of cells, Lysyl-tRNA synthetase binds to the transcription factors Microphthalmia-associated transcription factor, MITF and USF2 and can then influence their transcriptional activities. Such physiological stimulation includes immunological activation of mast cells, so this pathway maybe relevant to the allergic response. Interactions KARS (gene) has been shown to Protein-protein intera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NARS (gene)
Asparaginyl-tRNA synthetase, cytoplasmic is an enzyme that in humans is encoded by the ''NARS'' gene. Aminoacyl-tRNA synthetases are a class of enzymes that charge tRNAs with their cognate amino acids. Asparaginyl-tRNA synthetase is localized to the cytoplasm and belongs to the class II family of tRNA synthetases. The N-terminal domain represents the signature sequence for the eukaryotic Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacte ... asparaginyl-tRNA synthetases. References Further reading * * * * * * * * * * Human proteins {{gene-18-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NARS2
Nars or NARS may refer to: *Karl Nars (1874–1952), Finnish industrialist * Natural Area Reserves System such as the Natural Area Reserves System Hawaii *North Atlantic Radio System, a troposcatter communications system for the air defence of NATO's North-Eastern flank *NARS Cosmetics *NARS (gene) (Asparaginyl-tRNA synthetase, cytoplasmic), an enzyme in humans *Nested Arrays Research System ''Nested'' is the seventh studio album by Bronx-born singer, songwriter and pianist Laura Nyro, released in 1978 on Columbia Records. Following on from her extensive tour to promote 1976's ''Smile (Laura Nyro album), Smile'', which resulted in th ..., an extension of the APL programming language such as NARS2000 See also * Nar (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Families
A protein family is a group of evolutionarily related proteins. In many cases, a protein family has a corresponding gene family, in which each gene encodes a corresponding protein with a 1:1 relationship. The term "protein family" should not be confused with family as it is used in taxonomy. Proteins in a family descend from a common ancestor and typically have similar three-dimensional structures, functions, and significant sequence similarity. The most important of these is sequence similarity (usually amino-acid sequence), since it is the strictest indicator of homology and therefore the clearest indicator of common ancestry. A fairly well developed framework exists for evaluating the significance of similarity between a group of sequences using sequence alignment methods. Proteins that do not share a common ancestor are very unlikely to show statistically significant sequence similarity, making sequence alignment a powerful tool for identifying the members of protein familie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
