Figure 2.
Figure 2. Structure of SBD in complex with chitobiose. (a)
Stereo view of the difference-density map (F[o] - F[c] with
phase from the Fbs1 model) of binding chitobiose, contoured at
2.1 ,
modeled into the electron density. -strands
belonging to S1 and S2 are blue and red, respectively. Loops are
black. The bound chitobiose is orange, and the residues involved
in the substrate binding (FYWK, see Fig. 1c) are green. (b)
Molecular surface representation of the chitobiose-binding
region. The bound chitobiose is shown in ball-and-stick
representation. Two GlcNAc residues are represented by A and B.
Cyan spheres are two water molecules of wild type SBD that are
fixed on the molecular surface through hydrogen bonds with the
backbone N and O of Lys281, respectively. These water molecules
are replaced by O3 and O6 of the chitobiose upon formation of
the SBD -chitobiose complex. (c) Stick representation of the
amino acids involved in binding. Hydrogen bonds are dashed
lines. Oxygen and nitrogen are red and blue, respectively.
Symbols of two water molecules are as in b.
The above figure is reprinted
by permission from Macmillan Publishers Ltd:
Nat Struct Mol Biol
(2004,
11,
365-370)
copyright 2004.
,
modeled into the electron density. 
-strands
belonging to S1 and S2 are blue and red, respectively. Loops are
black. The bound chitobiose is orange, and the residues involved
in the substrate binding (FYWK, see Fig. 1c) are green. (b)
Molecular surface representation of the chitobiose-binding
region. The bound chitobiose is shown in ball-and-stick
representation. Two GlcNAc residues are represented by A and B.
Cyan spheres are two water molecules of wild type SBD that are
fixed on the molecular surface through hydrogen bonds with the
backbone N and O of Lys281, respectively. These water molecules
are replaced by O3 and O6 of the chitobiose upon formation of
the SBD -chitobiose complex. (c) Stick representation of the
amino acids involved in binding. Hydrogen bonds are dashed
lines. Oxygen and nitrogen are red and blue, respectively.
Symbols of two water molecules are as in b.