4wq5 | pdb_00004wq5
YgjD(V85E)-YeaZ heterodimer in complex with ATP
Structural highlights
Function[TSAD_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] [TSAB_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 TsaD and TsaE. TsaB seems to play an indirect role in the t(6)A biosynthesis pathway, possibly in regulating the core enzymatic function of TsaD. In fact, can act as a protease that specifically degrades TsaD in vitro; therefore TsaB may post-translationally regulate cellular pools of TsaD via proteolytic degradation. Does not show sialoglycoprotease activity against glycophorin A.[4] [5] 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[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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