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Figure 2.
Figure 2. Stereo pictures of selected sections of zmCK2a.
(a) The hypothetical benzamidine molecule (covered by blue
s[a]-weighted 2F[o] -F[c] electron density; no. 2 in Table 2)
within its protein environment (green electron density). The
corresponding room temperature structure (no. 1 in Table 2)
looks essentially identical (not shown). For comparision
equivalent parts of the zmCK2a/AMPPNP complex (no. 3 in Table 2)
are drawn in black. The hypothetical benzamidine molecule and
the adenine group of the bound AMPPNP molecule are almost
co-planar but do not overlap. Two alternative side-chain
conformations of Met163 are found in structure 2 of Table 2 but
only one of these is selected when AMPPNP is bound (black bonds;
black electron density). For comparison two further side-chain
conformations of Met163 are displayed as observed in
apo-zmCK2a^21 (brown) and in a zmCK2a complex with
4,5,6,7-tetrabromo-2-benzotriazole21 (magenta colour). All
pieces of electron density are drawn with a 1s contour level.
Some hydrogen bonds are indicated with pink broken lines. (b)
The divalent sulphur atom of Met163 (structure 3 of Table 2)
attached simultaneously to two p-systems, namely the adenine
group of AMPPNP and the terminal amide group of Asn118. The
final electron density is drawn in green with a contour level of
1s.
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