UniProt functional annotation for P00957



	UniProt functional annotation for P00957

UniProt code: P00957.

Organism: Escherichia coli (strain K12).

Taxonomy: Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales; Enterobacteriaceae; Escherichia.

Function: Catalyzes the attachment of L-alanine to tRNA(Ala) in a two- step reaction: L-alanine is first activated by ATP to form Ala-AMP and then transferred to the acceptor end of tRNA(Ala). AlaRS also incorrectly activates the sterically smaller amino acid glycine as well as the sterically larger amino acid L-serine; generates 2-fold more mischarged Gly than Ser (PubMed:28362257). These mischarged amino acids occur because the of inherent physicochemical limitations on discrimination between closely related amino acids (Ala, Gly and Ser) in the charging step. {ECO:0000269|PubMed:28362257}.

Function: Edits mischarged Ser-tRNA(Ala) and Gly-tRNA(Ala) but not incorrectly charged Ser-tRNA(Thr) (PubMed:12554667, PubMed:18723508). Dtd edits Gly-tRNA(Ala) 4-fold better than does AlaRS (PubMed:28362257). {ECO:0000269|PubMed:12554667, ECO:0000269|PubMed:18723508, ECO:0000269|PubMed:28362257}.

Function: Attaches Ala to transfer-messenger RNA (tmRNA, also known as 10Sa RNA, the product of the ssrA gene). tmRNA plays a major role in rescue of stalled ribosomes via trans-translation. {ECO:0000269|PubMed:7524073}.

Catalytic activity: Reaction=ATP + L-alanine + tRNA(Ala) = AMP + diphosphate + L-alanyl- tRNA(Ala); Xref=Rhea:RHEA:12540, Rhea:RHEA-COMP:9657, Rhea:RHEA- COMP:9923, ChEBI:CHEBI:30616, ChEBI:CHEBI:33019, ChEBI:CHEBI:57972, ChEBI:CHEBI:78442, ChEBI:CHEBI:78497, ChEBI:CHEBI:456215; EC=6.1.1.7;

Cofactor: Name=Zn(2+); Xref=ChEBI:CHEBI:29105; Note=Binds 1 zinc ion per subunit; it is not clear where this binding occurs. {ECO:0000269|PubMed:1712632};

Subunit: Homotetramer. {ECO:0000269|PubMed:7005211}.

Subcellular location: Cytoplasm.

Domain: Consists of three domains; the N-terminal catalytic domain, the editing domain and the C-terminal C-Ala domain. The editing domain removes incorrectly charged amino acids, while the C-Ala domain, along with tRNA(Ala), serves as a bridge to cooperatively bring together the editing and aminoacylation centers thus stimulating deacylation of misacylated tRNAs.

Domain: The editing domain removes incorrectly charged amino acids, i.e. Ser-tRNA(Ala) or Gly-tRNA(Ala) become uncharged tRNA(Ala) and the amino acid. It is specific for the acceptor stem of tRNA(Ala).

Domain: The C-terminal C-Ala domain, along with tRNA(Ala), serves as a bridge to cooperatively bring together the editing and aminoacylation centers thus stimulating deacylation of misacylated tRNAs. This C-Ala domain can be replaced in vitro by the corresponding domain of Aquifex aeolicus or man. Recognition of tRNA(Ala) by the 2 domains is independent, that is one enzyme recognizes the same tRNA(Ala) in 2 different manners. {ECO:0000305}.

Similarity: Belongs to the class-II aminoacyl-tRNA synthetase family. {ECO:0000305}.

Annotations taken from UniProtKB at the EBI.


Organism:		Escherichia coli (strain K12).
Taxonomy:		Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales; Enterobacteriaceae; Escherichia.



Function:		Catalyzes the attachment of L-alanine to tRNA(Ala) in a two- step reaction: L-alanine is first activated by ATP to form Ala-AMP and then transferred to the acceptor end of tRNA(Ala). AlaRS also incorrectly activates the sterically smaller amino acid glycine as well as the sterically larger amino acid L-serine; generates 2-fold more mischarged Gly than Ser (PubMed:28362257). These mischarged amino acids occur because the of inherent physicochemical limitations on discrimination between closely related amino acids (Ala, Gly and Ser) in the charging step. {ECO:0000269\|PubMed:28362257}.



Function:		Edits mischarged Ser-tRNA(Ala) and Gly-tRNA(Ala) but not incorrectly charged Ser-tRNA(Thr) (PubMed:12554667, PubMed:18723508). Dtd edits Gly-tRNA(Ala) 4-fold better than does AlaRS (PubMed:28362257). {ECO:0000269\|PubMed:12554667, ECO:0000269\|PubMed:18723508, ECO:0000269\|PubMed:28362257}.



Function:		Attaches Ala to transfer-messenger RNA (tmRNA, also known as 10Sa RNA, the product of the ssrA gene). tmRNA plays a major role in rescue of stalled ribosomes via trans-translation. {ECO:0000269\|PubMed:7524073}.


Catalytic activity:		Reaction=ATP + L-alanine + tRNA(Ala) = AMP + diphosphate + L-alanyl- tRNA(Ala); Xref=Rhea:RHEA:12540, Rhea:RHEA-COMP:9657, Rhea:RHEA- COMP:9923, ChEBI:CHEBI:30616, ChEBI:CHEBI:33019, ChEBI:CHEBI:57972, ChEBI:CHEBI:78442, ChEBI:CHEBI:78497, ChEBI:CHEBI:456215; EC=6.1.1.7;
Cofactor:		Name=Zn(2+); Xref=ChEBI:CHEBI:29105; Note=Binds 1 zinc ion per subunit; it is not clear where this binding occurs. {ECO:0000269\|PubMed:1712632};
Subunit:		Homotetramer. {ECO:0000269\|PubMed:7005211}.
Subcellular location:		Cytoplasm.
Domain:		Consists of three domains; the N-terminal catalytic domain, the editing domain and the C-terminal C-Ala domain. The editing domain removes incorrectly charged amino acids, while the C-Ala domain, along with tRNA(Ala), serves as a bridge to cooperatively bring together the editing and aminoacylation centers thus stimulating deacylation of misacylated tRNAs.
Domain:		The editing domain removes incorrectly charged amino acids, i.e. Ser-tRNA(Ala) or Gly-tRNA(Ala) become uncharged tRNA(Ala) and the amino acid. It is specific for the acceptor stem of tRNA(Ala).
Domain:		The C-terminal C-Ala domain, along with tRNA(Ala), serves as a bridge to cooperatively bring together the editing and aminoacylation centers thus stimulating deacylation of misacylated tRNAs. This C-Ala domain can be replaced in vitro by the corresponding domain of Aquifex aeolicus or man. Recognition of tRNA(Ala) by the 2 domains is independent, that is one enzyme recognizes the same tRNA(Ala) in 2 different manners. {ECO:0000305}.
Similarity:		Belongs to the class-II aminoacyl-tRNA synthetase family. {ECO:0000305}.