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Figure 3.
Active site of native LapB and its complexes. The active site
for substrate-free LapB and its complex with 4MC or product is
shown with a stick model, with a schematic representation of the
interactions shown in the right panel. The dashed lines indicate
putative hydrogen bonds, which are labeled with the average
interatomic distance (in Å), and the decorated arcs
represent van der Waals interactions of less than 4.0 Å.
A, the active site for substrate-free LapB in subunit B is
shown. Three water molecules depicted as red spheres occupy the
first coordination shell and interact with iron ion, a black
sphere. B, a 2F[o] − F[c] electron density map contoured at 1
σ is overlaid on the model of 4MC in the LapB-4MC complex
(subunit C). For clarity, Leu-156, which is also a part of the
active site, is not shown in this figure and also not shown in C
but is displayed in Fig. 1E. C, same as B except that
2-hydroxy-6-oxohepta-2,4-dienoic acid, the product of 3MC
produced via proximal cleavage by LapB, is shown with a 2F[o]
− F[c] electron density map contoured at 0.8 σ in subunit B.
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