Extended Data Fig. 8: The effects of eIF5B mutations on the kinetics of 60S joining and the transition to elongation.
From: eIF5B gates the transition from translation initiation to elongation
a, b, The cumulative probability distributions of the dwell times for 60S joining (a) and the transition to elongation (b) from experiments performed with unlabelled wild-type eIF5B (n = 164), the eIF5B(T439A) mutant (n = 131) or the eIF5B(H505Y) mutant (n = 119) and the model mRNA at 20 °C in the presence of 3 mM Mg2+ and 1 mM GTP. c, The estimated average fast and slow phase rates (kfast and kslow) and amplitudes (Afast and Aslow) of 60S joining (from a) and Δt values (from b) with the 95% confidence intervals from fitting the distributions to a double-exponential (wild-type eIF5B and eIF5B(H505Y)) or a single-exponential (eIF5B(T439A)) equation for the 60S joining; or to a single-exponential equation for the transition dwell times. ∗In the case of eIF5B(T439A), out of n = 131 molecules showing 60S joining signal, only n = 17 molecules showed the subsequent signal of aa-tRNA association with the A site. Thus, the eIF5B(T439A) mutant is defective in catalysing subunit joining (consistent with bulk measurement9), and inhibits tRNA association with the A site.
