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Figure 8.
Fig. 8. dTTP inhibition of the dUTPase reaction in dCTP
deaminase:dUTPase. Close-up of the active site (ribbon view)
from superposition of the apo form of M. tuberculosis dCTP
deaminase:dUTPase (green) and the dTTP complex (pink) with the
M. tuberculosis dUTPase–α,β-imido dUTP complex (orange, PDB
ID 1SIX^24). From all three structures the side chains
corresponding to Ser102, Asp119 and Gln148 are shown as well as
Ala115 from the bifunctional enzyme. Nucleotides are presented
in ball-and-stick representation and in standard atom colours
except carbon, which is coloured according to the matching
enzyme. Important water molecules are also shown in colours
corresponding to the colour of the matching enzyme. Magnesium
ions are grey. The active site is shown from two directions (a
and b). A continuous arrow points to the nucleophilic water
molecule, while a dotted arrow points to the water molecule that
is hydrogen-bonded to O2 of the α-phosphate in the trimeric
dUTPases. See the text for details. The panels were prepared
with PyMol (DeLano Scientific).
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