Fig. 1: Substrate tRNA adopts two distinct conformations when bound to KEOPS.
From: Structures of KEOPS bound to tRNA reveal functional roles of the kinase Bud32
A Schematic of the t6A tRNA modification pathway in archaea and eukaryotes. TsaC/Sua5 enzymes utilize bicarbonate, threonine and ATP to generate threonylcarbamoyl adenylate (TC-AMP). TC-AMP is utilized by the KEOPS subunit Kae1 to t6A modify N6 of A37 with the threonylcarbamoyl group of TC-AMP thereby generating AMP. Kae1 functions with other KEOPS complex members Cgi121, the kinase ATPase Bud32, Pcc1 and Gon7. t6A modification also requires ATP hydrolysis to ADP + Pi by Bud32. B, C Cryo-EM density maps of KEOPS bound to tRNA in a native-like conformation at 3.56 Å resolution (B) and bound to tRNA in a distorted conformation at 3.59 Å resolution (C). D, E Zoom-in side views of the tRNA in its native-like (D) and distorted tRNA conformations (E) highlighting the conformational differences in the anticodon domain when bound to KEOPS.
