Download citation
Download citation
link to html
N6-Threonylcarbamoyladenosine (t6A) is a modified tRNA base required for accuracy in translation. Qri7 is localized in yeast mitochondria and is involved in t6A biosynthesis. In t6A biosynthesis, threonylcarbamoyl-adenylate (TCA) is synthesized from threonine, bicarbonate and ATP, and the threonyl-carbamoyl group is transferred to adenine 37 of tRNA by Qri7. Qri7 alone is sufficient to catalyze the second step of the reaction, whereas the Qri7 homologues YgjD (in bacteria) and Kae1 (in archaea and eukaryotes) function as parts of multi-protein complexes. In this study, the crystal structure of Qri7 complexed with AMP (a part of TCA) has been determined at 2.94 Å resolution in a new crystal form. The manner of AMP recognition is similar, with some minor variations, among the Qri7/Kae1/YgjD family proteins. The previously reported dimer formation was also observed in this new crystal form. Furthermore, a comparison with the structure of TobZ, which catalyzes a similar reaction to t6A biosynthesis, revealed the presence of a flexible loop that may be involved in tRNA binding.

Supporting information

PDB reference: Qri7, 3wuh


Follow Acta Cryst. F
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds