Exploring the targeting spectrum of rocaglates among eIF4A homologs

Rocaglates induce clamping of eIF4A3 to polypurine RNA. (A) Overlay of the eIF4A1•AMPPNP•DMPatA•poly r(AG)₅ RNA complex (PDB:6XKI) (Naineni et al. 2021) with the crystal structure of human eIF4A3 bound to RNA (PDB:2HYI) (Andersen et al. 2006). The relative location of amino acids from eIF4A1 and eIF4A3 interacting with, or in proximity to, DMPatA are shown. (Ade) Adenine, (Gua) guanine. (B) Overlay of the eIF4A1•AMPPNP•RocA•poly r(AG)₅ RNA complex (PDB:5ZC9) (Iwasaki et al. 2019) with the crystal structure of human eIF4A3 bound to RNA (PDB:2HYI) (Andersen et al. 2006). The relative location of amino acids from eIF4A1 and eIF4A3 interacting with, or in proximity to, RocA are shown. (Ade) Adenine, (Gua) guanine. (C) Rocaglates stabilize binding of eIF4A3 to poly r(AG)₈. The ΔmP obtained with eIF4A1 or eIF4A3 with poly r(AG)₈ RNA and the indicated compounds (10 µM) was measured. The ΔmP obtained is relative to DMSO control. n = 3 ± SD. (D) eIF4A3^F168L and eIF4A3^Q200L mutants are not substrates for rocaglate-induced clamping. The ΔmP obtained with eIF4A1 or eIF4A3 mutants with poly r(AG)₈ RNA and the indicated compounds (10 µM) was assessed. n = 3 ± SD. (E) ATPase activity of eIF4A1 and eIF4A3 protein preparations used in this study. n = 3 ± SD. (F) Relative dissociation of complexes preformed in the presence of eIF4A1 or eIF4A3, ATP (1 mM), and compound (10 µM) measured as a function of time in the presence of 1000-fold molar excess of unlabeled poly r(AG)₈ RNA.