Sites of hydroxylation of progesterone by P450 17A1.
A, chair configuration of progesterone, with
the four sites of attack indicated by arrows.
B, wire diagram of 17α-hydroxyprogesterone
(17OHP, red) and
16α,17α-dihydroxyprogesterone
(16,17OHP, blue) overlaid,
with the latter in an alternative configuration to show the
proximity of the C-6 atom of
16α,17α-hydroxyprogesterone with the 17-hydroxy
group of 17α-hydroxyprogesterone. The model was made using
Chem3D, with a minimum root mean square error of 0.1 and minimum
root mean square gradient of 0.01. The C14, C10, and O3 atoms of
17α-hydroxyprogesterone were aligned with the C10, C14,
and O16 atoms of 16α,17α-dihydroxyprogesterone,
respectively, by displaying the distance measurements of each
pair of atoms and then running an overlay minimization
calculation. The green lines indicate the pair
of atoms that were aligned (after overlay minimization, the
distances between C14 of 17-OHP and C10 of 16,17-OHP; C10 of
17-OHP and C14 of 16,17-OHP; and O3 of 17-OHP and O17 of
16,17-OHP were 1.2, 1.3, and 1.4 Å, respectively, and are
shown as green lines). The distance between the
O17 atom of 17α-hydroxyprogesterone and C6 atom of
16α,17α-dihydroxyprogesterone was 1.4 Å.