FIGURE 4.
|Fo| − |Fc| omit electron density maps of resting ThDP (A), AcThDP (B), DHEThDP (C), Pi complex (D), and tricyclic ring form of ThDP in H64A mutant (E). The maps were contoured at 4σ (A, B, D, and E) or 3σ (C). A, a catalytically important Glu-479 residue is also shown. Interactions between the N4′ group of pyrimidine and the reactive C2 atom of the thiazolium ring and between the N1′ atom of the pyrimidine and Glu479 are shown as dotted lines. B, the inset shows planarity of the acetyl group. C, this panel is stereographic. The inset shows nonplanarity of the DHE moiety. E, the mutated Ala-64 residue is also shown.