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Figure 1.
Figure 1. (A) The PfGAPDH monomer. The NAD^+-binding domain is
shown in blue, the meandering S-loop in red, and the remainder
of the catalytic domain in green. NAD^+ is shown as a
ball-and-stick model, together with two strictly conserved
catalytic residues, Cys153 and His180 (where carbon is gold,
nitrogen is blue, oxygen is red, phosphate is purple, and
sulphur is green). In simple black stick model are represented:
Met38 and Lys194-Gly195, identified as potentially significant
based on a previous analysis of differences between the
experimental rabbit structure and a PfGAPDH homology model.[8]
In purple is depicted the position of AEBSF which has been
modeled into the islands of extra density (See Fig. 2). (B) The
PfGAPDH tetramer. The PfGAPDH tetramer shows the deep grooves
between the O-R and the P-Q NAD^+-binding sites. The S-loops are
colored red, showing the raised plateau these loops form between
adjacent pairs of the NAD^+-binding sites. The secondary
structure elements of the C-terminal domain are depicted with
thinner helices and strands than in the catalytic domain to help
distinguish the two domains. The O and P subunits are shown in
lighter colors for contrast with the Q and R subunits. NAD^+ is
shown in CPK representation. The additional unknown compound is
shown as a smaller ball-and-stick model in purple, labeled
ligand. (C) Electrostatic environment of the NAD^+ binding
groove. Comparison of the electrostatic surface[43-45]
representation of the NAD^+ binding groove: PfGAPDH versus
HumanGAPDH. In PfGAPDH, the walls and the roof of the
NAD^+-binding cavity are more closed and there is a small bulge
due to the - KG - insertion.
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