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Figure 3.
Figure 3. The chemical similarity of the RARg-selective
BMS184394 and the RARb,g-selective CD564 allows to attribute
their different selectivity to their respective hydroxyl and
keto groups (stereo views). (a) Final model of the BMS184394
complex depicted with the initial refinement-unbiased
s[A]-weighted mF[o] -F[c] omit map (colored in violet) at 1.47
Å resolution contoured at 3.2s. The protein part is
colored in green and the ligand in red. Although a racemic
mixture has been used in co-crystallization only the
R-enantiomer of BMS184394 is present exhibiting a hydrogen bond
to the Met272 sulfur atom. (b) The CD564 complex with the ligand
fitted to its electron density (s[A]-weighted mF[o] -F[c] omit
map at 1.30 Å resolution contoured at 3.2s, colored in
orange). The protein part is colored in blue and the ligand in
orange. (c) The pocket superposition obtained by a least-squares
fit of the BMS184394 and CD564 complexes illustrates that the
conformation of the Met272 side-chain depends on the interaction
pattern with the ligand. The movement of Met272 is mediated to
Ile389 and Leu386. Note that Ile389 and Ser390 exhibit two
independent conformations for each structure that are depicted
in green and yellow for the BMS184394 complex and in blue and
violet for the CD564 complex.
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