3ip4
The high resolution structure of GatCABThe high resolution structure of GatCAB
Structural highlights
FunctionGATA_STAAM Allows the formation of correctly charged Gln-tRNA(Gln) through the transamidation of misacylated Glu-tRNA(Gln) in organisms which lack glutaminyl-tRNA synthetase. The reaction takes place in the presence of glutamine and ATP through an activated gamma-phospho-Glu-tRNA(Gln) (By similarity). Evolutionary Conservation![]() Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedIn many prokaryotes the biosynthesis of the amide aminoacyl-tRNAs, Gln-tRNA(Gln) and Asn-tRNA(Asn), proceeds by an indirect route in which mischarged Glu-tRNA(Gln) or Asp-tRNA(Asn) is amidated to the correct aminoacyl-tRNA catalyzed by a tRNA-dependent amidotransferase (AdT). Two types of AdTs exist: bacteria, archaea and organelles possess heterotrimeric GatCAB, while heterodimeric GatDE occurs exclusively in archaea. Bacterial GatCAB and GatDE recognize the first base pair of the acceptor stem and the D-loop of their tRNA substrates, while archaeal GatCAB recognizes the tertiary core of the tRNA, but not the first base pair. Here, we present the crystal structure of the full-length Staphylococcus aureus GatCAB. Its GatB tail domain possesses a conserved Lys rich motif that is situated close to the variable loop in a GatCAB:tRNA(Gln) docking model. This motif is also conserved in the tail domain of archaeal GatCAB, suggesting this basic region may recognize the tRNA variable loop to discriminate Asp-tRNA(Asn) from Asp-tRNA(Asp) in archaea. Furthermore, we identified a 3(10) turn in GatB that permits the bacterial GatCAB to distinguish a U1-A72 base pair from a G1-C72 pair; the absence of this element in archaeal GatCAB enables the latter enzyme to recognize aminoacyl-tRNAs with G1-C72 base pairs. Two distinct regions in Staphylococcus aureus GatCAB guarantee accurate tRNA recognition.,Nakamura A, Sheppard K, Yamane J, Yao M, Soll D, Tanaka I Nucleic Acids Res. 2010 Jan;38(2):672-82. Epub 2009 Nov 11. PMID:19906721[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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