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162 Chapter 7
Figure 7.6 Active site of Escherichia coli fructose-1,6-bisphosphate aldolase (PDB Wle 1B57), a class
II aldolase. Bound substrate analogue phosphoglycolohydroxamate and Zn 2þ cofactor shown in
black. Catalytic residues Asp-109 (bottom) and Glu-182 (top left), and Zn 2þ ligands shown in red.
Glu 182
O −
O
H S
H R
OPO 3
2−
O
H
O
2+
Zn
NHis
NHis
NHis
2− O 3 PO
O
Asp 109
O
H
H
OH
O
H
H
OPO 3
2−
O
H
O −
2+
Zn
NHis
NHis
NHis
2− O3 PO
H
OH
OPO 3
2−
HO
O −
O
H
H
O
H
O
2+
Zn
NHis
NHis
NHis
Asp 109
Figure 7.7 Mechanism for Eschericha coli class II fructose-1,6-biphosphate aldolase.