4wq4
E. coli YgjD(E12A)-YeaZ heterodimer in complex with ATP
Structural highlights
FunctionTSAD_ECOLI Required for the formation of a threonylcarbamoyl group on adenosine at position 37 (t(6)A37) in tRNAs that read codons beginning with adenine. Is probably involved in the transfer of the threonylcarbamoyl moiety of threonylcarbamoyl-AMP (TC-AMP) to the N6 group of A37, together with TsaE and TsaB. TsaD likely plays a direct catalytic role in this reaction. May also be involved in the metabolism of glycated proteins, but does not show sialoglycoprotease activity against glycophorin A.[1] [2] [3] Publication Abstract from PubMedThe essential and universal N6-threonylcarbamoyladenosine (t6A) modification at position 37 of ANN-decoding tRNAs plays a pivotal role in translational fidelity through enhancement of the cognate codon recognition and stabilization of the codon-anticodon interaction. In Escherichia coli, the YgjD (TsaD), YeaZ (TsaB), YjeE (TsaE) and YrdC (TsaC) proteins are necessary and sufficient for the in vitro biosynthesis of t6A, using tRNA, ATP, L-threonine and bicarbonate as substrates. YrdC synthesizes the short-lived L-threonylcarbamoyladenylate (TCA), and YgjD, YeaZ and YjeE cooperate to transfer the L-threonylcarbamoyl-moiety from TCA onto adenosine at position 37 of substrate tRNA. We determined the crystal structure of the heterodimer YgjD-YeaZ at 2.3 A, revealing the presence of an unexpected molecule of ADP bound at an atypical site situated at the YgjD-YeaZ interface. We further showed that the ATPase activity of YjeE is strongly activated by the YgjD-YeaZ heterodimer. We established by binding experiments and SAXS data analysis that YgjD-YeaZ and YjeE form a compact ternary complex only in presence of ATP. The formation of the ternary YgjD-YeaZ-YjeE complex is required for the in vitro biosynthesis of t6A but not its ATPase activity. The ATP-mediated formation of the YgjD-YeaZ-YjeE complex is required for the biosynthesis of tRNA t6A in Escherichia coli.,Zhang W, Collinet B, Perrochia L, Durand D, van Tilbeurgh H Nucleic Acids Res. 2015 Jan 10. pii: gku1397. PMID:25578970[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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