Fig. 5.

AFPA as a molecular probe in the Eb/O domain and in Asp-AT (as a control). (A) PLP-AFPA external aldimine is bound to the EB/O domain. Two sets of simulated annealing electron density omit maps (Fo-Fc) are shown. Both are shown at 3.5 σ. The gray map was generated omitting the complete ligand adducts, confirming the existence of the ligands. The green map was generated omitting only the fluorine atom, confirming the existence of fluorine in AFPA. (B) Electron density omit map of the E. coli Asp-AT–AFPA–PLP complex, generated by omitting AFPA, PLP, and lysine 246 from the calculation. *Indicates that R280 is from a different subunit of the Asp-AT dimer.