Figure 5.

Phosphopantetheinyl amide NMR signals from holo-ArCP show a complex response to binding by YbtE. A–E, proximal amide group (p in Fig. 1). A, two signals can be observed in free holo-ArCP (100 μm). As the concentration of YbtE is increased to 12.5 μm (B), 25 μm (C) 37.5 μm (D), and 50 μm (E), the signal marked with a blue plus shifts significantly and decreases in intensity, whereas the minor signal, marked with a black cross, shows little change in chemical shift. New signals also begin to appear, although it is not possible to assign them to either the major or minor PP signal. F–J, the distal group (d in Fig. 1) is also subject to an unusual perturbation, although spectral crowding hampers the interpretation. The question marks emphasize perturbations of ambiguous origin. The cross and plus symbols are not meant to be related with those used in A–E.