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Figure 4.
Figure 4. Structural characterisation of the mutant
hsCK2a^1-335-V66A/M163L. (a) Stereo picture of the AMPPNP
molecule (covered by blue s[a]-weighted 2F[o] -F[c] electron
density contoured at 1s) and a part of its protein environment
(green density). For comparision the equivalent sections of the
zmCK2a/AMPPNP structure (structure no. 3 in Table 2) are drawn
with black carbon atoms. (b) The adenine group of AMPPNP and its
flanking side-chains in hsCK2a^1-335-V66A/M163L (covered by
green electron density), in hsCK2a^1-335 (blue bonds), in zmCK2a
(structure no. 3 of Table 2; black bonds) and in CAPK (magenta
bonds). (c) Main chain atom RMS deviations after superimposition
of the structures of hsCK2a^1-335 and hsCK2a^1-335-V66A/M163L.
(d) Stereo picture to illustrate the structural variation in the
helix aD region. While zmCK2a (black trace) and hsCK2a^1-335
(blue trace) deviate strongly from CAPK (magenta trace) in this
region, hsCK2a^1-335-V66A/M163L (yellow trace) is much more
similar to it. As a consequence the space at the entrance to the
purine base binding plane is restricted and the binding of
GMPPNP (and GTP) is hampered.
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