The human histidyl-tRNA synthetase (HRS) gene encodes an enzyme that catalyzes the esterification of histidine to its cognate tRNA as an early step in protein biosynthesis. Previous reports have described a bidirectional promoter element which coordinates the transcription of both HRS and an unknown mRNA whose gene is oriented in a head-to-head configuration with HRS. We have isolated and characterized a human genomic DNA clone that encodes portions of these oppositely transcribed mRNAs and a putatively full-length cDNA clone (HO3) corresponding to the gene mapping immediately 5' of HRS. The largest open reading frame within HO3 (1518 bp) shares approximately 75% nucleotide sequence identity with human HRS (1527 bp) and predicts a polypeptide with extensive amino acid sequence homology with the HRS protein (72%). Moreover, amino acid sequence motifs characteristic of class II aminoacyl-tRNA synthetases are conserved within HO3. Despite their similarity, HRS and HO3 have divergent amino-terminal domains which correspond to the first two exons of each gene. RNA blot analysis revealed that HRS (2.0 kb) and HO3 (2.5 kb) exhibit distinct patterns of steady-state mRNA expression among multiple human tissues.
The process of coupling histidine to histidyl-tRNA, catalyzed by histidyl-tRNA synthetase. In tRNA aminoacylation, the amino acid is first activated by linkage to AMP and then transferred to either the 2'- or the 3'-hydroxyl group of the 3'-adenosine residue of the tRNA.
The cellular metabolic process in which a protein is formed, using the sequence of a mature mRNA molecule to specify the sequence of amino acids in a polypeptide chain. Translation is mediated by the ribosome, and begins with the formation of a ternary complex between aminoacylated initiator methionine tRNA, GTP, and initiation factor 2, which subsequently associates with the small subunit of the ribosome and an mRNA. Translation ends with the release of a polypeptide chain from the ribosome.
The human histidyl-tRNA synthetase (HRS) gene encodes an enzyme that catalyzes the esterification of histidine to its cognate tRNA as an early step in protein biosynthesis. Previous reports have described a bidirectional promoter element which coordinates the transcription of both HRS and an unknown mRNA whose gene is oriented in a head-to-head configuration with HRS. We have isolated and characterized a human genomic DNA clone that encodes portions of these oppositely transcribed mRNAs and a putatively full-length cDNA clone (HO3) corresponding to the gene mapping immediately 5' of HRS. The largest open reading frame within HO3 (1518 bp) shares approximately 75% nucleotide sequence identity with human HRS (1527 bp) and predicts a polypeptide with extensive amino acid sequence homology with the HRS protein (72%). Moreover, amino acid sequence motifs characteristic of class II aminoacyl-tRNA synthetases are conserved within HO3. Despite their similarity, HRS and HO3 have divergent amino-terminal domains which correspond to the first two exons of each gene. RNA blot analysis revealed that HRS (2.0 kb) and HO3 (2.5 kb) exhibit distinct patterns of steady-state mRNA expression among multiple human tissues.
Protein involved in the biosynthesis of proteins from mRNA molecules. This process, called translation, is carried out by ribosomes, where activated amino acids are added to the nascent polypeptide chain.
Enzyme that activates an amino acid for translation by forming an aminoacyladenylate intermediate and then links this activated amino acid to the corresponding tRNA molecule (amino acid-tRNA, aminoacyl- tRNA). In general, a specific aminoacyl-tRNA synthase is available for each amino acid.
Enzyme that catalyzes the joining of two molecules coupled with the breakdown of a pyrophosphate bond in ATP or a similar triphosphate. Sometimes the terms "synthase", "synthetase" or "carboxylase" are also used for this class of enzymes.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.
My favorites 
My labels 
Login
