Figure 2.

GTP binding enhances the rate of nucleotide exchange

(A) Diagrammatic representation of assay monitoring release of BODIPY GDP from eIF2 in the presence of excess unlabeled GDP.

(B) Only GTP boosts K_off of eIF2B. GDP dissociation assays were performed with eIF2B preincubated with increasing [GTP], [GDP] (top), [ATP], or [ADP] (bottom); K_max and K_1/2 were calculated from the line of best fit, as described in the STAR Methods.

(C) GTP boosts K_off at physiological [eIF2:eIF2B] 8:1. n = 3 ± s.e.m, one-tailed t test.

See also Figure S2.