Figure 2.

eIF5A-independent synthesis of homopolymers of azetidine-2-carboxylic acid (AZC), but not of other proline analogs. Maximum fractions of MPPPK peptide synthesis in elongation assays (Supplementary Figure S2) performed with the indicated proline analogs (1, l-proline; 2, α-methyl-l-proline; 3, 3,4-dehydro-dl-proline; 4, cis-4-hydroxy-l-proline; 5, pipecolic acid; 6, l-azetidine-2-carboxylic acid) in the presence of 1 mM spermidine and in the absence (white bars) or presence (black bars) of 5 μM hypusinated eIF5A. (Bottom) Fold stimulation of Y_max by eIF5A was calculated for each reaction in the upper panel (see also Supplementary Figure S2). Error bars are SD from at least three independent experiments (A) and calculated propagated SD (B).