Figure 2.
(a) Active site of pST3Gal-I, with CMP occupying the donor
site and Gal 1,3GalNAc
-PhNO[2]
disaccharide defining the acceptor site (yellow carbon atoms).
Amino acids of interest are shown as sticks, with the catalytic
base represented in cyan. Black dotted lines indicate potential
hydrogen bonds. For Gal 1,3GalNAc
-PhNO[2],
the unbiased 1.25-Å |F[o]| - |F[c]|, [calc]
electron density map is shown, contoured at 2 .
For CMP, the unbiased 1.55-Å |F[o]| - |F[c]|, [calc]
electron density map is shown, contoured at 2 .
(b) Observed disaccharide acceptor binding in pST3Gal-I (yellow)
with a model of CMP3F-NeuAc (green) based on the
CstII–CMP3F-NeuAc complex (PDB 1RO7)^18.
The above figure is reprinted
by permission from Macmillan Publishers Ltd:
Nat Struct Biol
(2009,
16,
1186-1188)
copyright 2009.
1,3GalNAc
-PhNO[2]
disaccharide defining the acceptor site (yellow carbon atoms).
Amino acids of interest are shown as sticks, with the catalytic
base represented in cyan. Black dotted lines indicate potential
hydrogen bonds. For Gal 
[calc]
electron density map is shown, contoured at 2 
.
For CMP, the unbiased 1.55-Å |F[o]| - |F[c]|,