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Figure 5.
Figure 5. Stereo pictures showing the environment of residue 165 in cadmium-containing structures of wild-type
CaMDH (A) and the E165Q (B) and E165K (C) mutants. (B) and (C) show 2F oKFc maps contoured at 1s for residue 165 to
illustrate the conformation of the side-chains as well as the general quality of the refinement. Red spheres represent
water molecules; the yellow sphere represents cadmium. In CaMDH (A) the negatively charged Glu165 binds directly to
one of the cadmium ions in the structure (closest distance 2.5 A
š
). In the E165Q mutant (B) the cadmium ion binds to
residue 165 via a water molecule (closest Cd
2C
-165 distance 4.2 A
š
). In the E165K mutant (A) the cadmium ion has moved
even further away from its original position and is now very close (2.3 A
š
, as compared to 4.2 A
š
in the wild-type) to
Glu238 of the other monomer. The distance between cadmium and the z-amino group of Lys165 is 4.1 A
š
. Figure 1 and
this Figure were made using the programs Bobscript
64
and Raster 3D.
65
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