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1.
Here the enzyme is shown in its entirety. It is drawn in the
same way as on the previous page with alpha helices in pink,
beta sheets in yellow, and regions without secondary structure
in white. The Heme is drawn in wireframe. Shown in blue are amino
acid differences between chimpanzees and humans. The amino acid
substitutions may have been triggered by an increased load of
dietary anabolic steroids, leading to a novel defense
mechanism against cholestasis.
2. Drawn
in the same way as 1. Human 3A4 is now bound to Erythromycin, an
antibiotic. in the absence of CYP3A4 Erythromycin has a half
life of 6 hours compared to 2 hours in a healthy individual,
significantly changing the pharmicokinetics.
3.
Now the protein is drawn in CPK to better display the channel
leading to the heme, in this structure occupied by Erythromycin.
The channel is larger than in other Cytochrome P450 and allows
for higher substrate specificity. The residues are colored the
same and the drawing of the Heme and ligand are unchanged.
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