HMM Summary Page: TIGR00132

Functionaspartyl/glutamyl-tRNA(Asn/Gln) amidotransferase, A subunit
Gene SymbolgatA
Trusted Cutoff481.10
Domain Trusted Cutoff481.10
Noise Cutoff399.35
Domain Noise Cutoff399.35
Isology Typeequivalog
EC Number6.3.5.-
HMM Length466
Mainrole CategoryProtein synthesis
Subrole CategorytRNA aminoacylation
Gene Ontology TermGO:0006424: glutamyl-tRNA aminoacylation biological_process
GO:0030956: glutamyl-tRNA(Gln) amidotransferase complex cellular_component
GO:0050567: glutaminyl-tRNA synthase (glutamine-hydrolyzing) activity molecular_function
AuthorHaft DH
Entry DateApr 20 1999 2:07PM
Last ModifiedFeb 14 2011 3:27PM
CommentIn many species, Gln--tRNA ligase is missing. tRNA(Gln) is misacylated with Glu after which a heterotrimeric amidotransferase converts Glu to Gln. This HMM represents the amidase chain of that heterotrimer, encoded by the gatA gene. In the Archaea, Asn--tRNA ligase is also missing. This amidase subunit may also function in the conversion of Asp-tRNA(Asn) to Asn-tRNA(Asn), presumably with a different recognition unit to replace gatB. Both Methanococcus jannaschii and Methanobacterium thermoautotrophicum have both authentic gatB and a gatB-related gene, but only one gene like gatA. It has been shown that gatA can be expressed only when gatC is also expressed. In most species expressing the amidotransferase, the gatC ortholog is about 90 residues in length, but in Mycoplasma genitalium and Mycoplasma pneumoniae the gatC equivalent is as the C-terminal domain of a much longer protein. Not surprisingly, the Mycoplasmas also represent the most atypical lineage of gatA orthology. This orthology group is more narrowly defined here than in Proc Natl Acad Aci USA 94, 11819-11826 (1997). In particular, a Rhodococcus homolog found in association with nitrile hydratase genes and described as an enantiomer-selective amidase active on several 2-aryl propionamides, is excluded here. It is likely, however, that the amidase subunit GatA is not exclusively a part of the Glu-tRNA(Gln) amidotransferase heterotrimer and restricted to that function in all species.
ReferencesSE TIGR GA hmmls AL clustalw RM 98004482 RT Glu-tRNAGln amidotransferase: a novel heterotrimeric enzyme required for correct decoding of glutamine codons during translation. RA Curnow AW, Hong Kw, Yuan R, Kim Si, Martins O, Winkler W, Henkin TM, Soll D RL Proc Natl Acad Sci U S A 1997 Oct 28;94(22):11819-26 DR HAMAP; MF_00120; 407 of 409
Genome PropertyGenProp0188: GatABC aspartyl/glutamyl-tRNA(Asn/Gln) amidotransferase complex (HMM)
GenProp0258: tRNA aminoacylation (HMM)
GenProp0258: tRNA aminoacylation (HMM)