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
|
| ||||||||||||||||||