Summary: Glycyl-tRNA synthetase alpha subunit
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Glycyl-tRNA synthetase alpha subunit Provide feedback
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This tab holds annotation information from the InterPro database.
InterPro entry IPR002310This entry represents the alpha subunit of glycine-tRNA ligase (also known as Glycyl-tRNA synthetase alpha subunit).
In eubacteria, glycine-tRNA ligase(EC) is an alpha2/beta2 tetramer composed of 2 different subunits [PUBMED:6309809, PUBMED:7962006, PUBMED:7665503]. In some eubacteria, in archaea and eukaryota, glycine-tRNA ligase is an alpha2 dimer (see INTERPRO). It belongs to class IIc and is one of the most complex ligases. What is most interesting is the lack of similarity between the two types: divergence at the sequence level is so great that it is impossible to infer descent from common genes. The alpha and beta subunits (see INTERPRO) also lack significant sequence similarity. However, they are translated from a single mRNA [PUBMED:6309809], and a single chain glycine-tRNA ligase from Chlamydia trachomatis has been found to have significant similarity with both domains, suggesting divergence from a single polypeptide chain [PUBMED:7665503].
The aminoacyl-tRNA synthetase (also known as aminoacyl-tRNA ligase) 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 [PUBMED:2203971]. 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 [PUBMED:10673435]. Class II aminoacyl-tRNA synthetases share an anti-parallel beta-sheet fold flanked by alpha-helices [PUBMED:8364025], and are mostly dimeric or multimeric, containing at least three conserved regions [PUBMED:8274143, PUBMED:2053131, PUBMED:1852601]. 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 arginine, cysteine, glutamic acid, glutamine, isoleucine, leucine, methionine, tyrosine, tryptophan and valine belong to class I synthetases. The synthetases specific for alanine, asparagine, aspartic acid, glycine, histidine, lysine, phenylalanine, proline, serine, and threonine belong to class-II synthetases. Based on their mode of binding to the tRNA acceptor stem, both classes of tRNA synthetases have been subdivided into three subclasses, designated 1a, 1b, 1c and 2a, 2b, 2c.
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Cellular component||cytoplasm (GO:0005737)|
|Molecular function||glycine-tRNA ligase activity (GO:0004820)|
|ATP binding (GO:0005524)|
|nucleotide binding (GO:0000166)|
|Biological process||glycyl-tRNA aminoacylation (GO:0006426)|
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Aminoacyl-tRNA synthetases are key components of the protein translation machinery that catalyse two basic reactions. First, the activation of amino acids via the formation of aminoacyl adenylates and second, linking the activated amino acid to the cognate tRNAs. The aminoacyl-tRNA synthetases generate AMP as the second end product of this reaction, which differentiates them from the majority of ATP-dependent enzymes that produce ADP. In addition, there is a specific aminoacyl-tRNA synthetases for each of the 20 amino acids and there are two structurally distinct classes of aminoacyl-tRNA synthetases, each encompassing 10 different specificities. The two classes have alternative modes of aminoacylation: class I aminoacylate the 2'OH of the cognate tRNA; class II aminoacylate 3'OH (with the exception of PheRS). Each class contain a conserved core domain that is involved in ATP binding and hydrolysis and combines with additional domains that determine the specificity of interactions with the cognate amino acid and tRNA. The class II core domain consist of a mixed-beta sheet, similar to that found in the biotin synthetases, hence why this family has also been included in this clan. The core domain contains three modestly conserved motifs that are responsible for ATP binding. The class II aminoacyl-tRNA synthetases can contain additional nested domains, found inserted in the loops of the core domain  (and reference therein).
The clan contains the following 10 members:AsnA BPL_LplA_LipB BPL_LplA_LipB_2 DUF366 tRNA-synt_2 tRNA-synt_2b tRNA-synt_2c tRNA-synt_2d tRNA-synt_2e tRNA-synt_His
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Curation and family details
|Author:||Mian N, Bateman A|
|Number in seed:||195|
|Number in full:||898|
|Average length of the domain:||277.80 aa|
|Average identity of full alignment:||62 %|
|Average coverage of the sequence by the domain:||78.75 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 11927849 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||12|
|Download:||download the raw HMM for this family|
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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the tRNA-synt_2e domain has been found. There are 8 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.
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