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Figure 2.
Figure 2. Overall Structure of the Heterotrimeric PP2A
Holoenzyme Involving the Bα Subunit
(A) Overall structure
of the PP2A holoenzyme involving the Bα subunit and bound to
MCLR. The scaffold (Aα), catalytic (Cα), and regulatory B
(Bα) subunits are shown in yellow, green, and blue,
respectively. MCLR is shown in magenta. Bα primarily interacts
with Aα through an extensive interface. Cα interacts with Aα
as described (Xing et al., 2006). Two views are shown here to
reveal the essential features of the holoenzyme.
(B) The
regulatory Bα subunit contains a highly acidic top face and a
hairpin arm. The electrostatic surface potential of Bα is
shown. Aα and Cα are shown in backbone worm.
(C)
Comparison of the distinct conformations of the A subunit in the
PP2A core enzyme and in the two holoenzymes. Figures 2B, 3C, and
5C were prepared using GRASP (Nicholls et al., 1991); all other
structural figures were made using MOLSCRIPT (Kraulis, 1991).
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