Figure 3.
Fig. 3. Schematic representation of the interactions between
Smad2 and SARA. (A) The interactions are predominantly
hydrophobic in nature. The surface of Smad2 MH2 domain is
represented by degrees of hydrophobicity. The C backbone
of SARA SBD is shown in pink and the buried hydrophobic residues
are highlighted in orange. This figure was prepared with GRASP
(25). (B) A closeup view of the interactions between the rigid
coil of SARA and the strands B8 and B9 of Smad2. Smad2 and SARA
are colored green and pink, respectively. The interacting side
chains are shown in yellow for Smad2 and in purple for SARA. The
O and N atoms are shown as red and blue balls, respectively. The
left panel shows the interface, whereas the right panel shows
the conformation of the rigid coil by itself. Aside from
extensive van der Waals interactions at the interface, there are
a total of five intermolecular H bonds. These include: Ser671 O
to Tyr366
carbonyl, Pro672 carbonyl to Trp368 N 1, Tyr680
O to Lys375
amide, Ser682 amide to Asn381 carbonyl, and Ser682 carbonyl to
Asn381 amide. (C) A closeup view of the interactions between the
helix of
SARA and strands B5 and B6 of Smad2. Color coding scheme is
identical to (B). (D) A closeup view of the interactions between
the strand of
SARA and the three-helix bundle and strand B1' of Smad2.
The above figure is reprinted
by permission from the AAAs:
Science
(2000,
287,
92-97)
copyright 2000.
backbone
of SARA SBD is shown in pink and the buried hydrophobic residues
are highlighted in orange. This figure was prepared with GRASP
(25). (B) A closeup view of the interactions between the rigid
coil of SARA and the strands B8 and B9 of Smad2. Smad2 and SARA
are colored green and pink, respectively. The interacting side
chains are shown in yellow for Smad2 and in purple for SARA. The
O and N atoms are shown as red and blue balls, respectively. The
left panel shows the interface, whereas the right panel shows
the conformation of the rigid coil by itself. Aside from
extensive van der Waals interactions at the interface, there are
a total of five intermolecular H bonds. These include: Ser671 O
to Tyr366
carbonyl, Pro672 carbonyl to Trp368 N 
1, Tyr680
O 
to Lys375
amide, Ser682 amide to Asn381 carbonyl, and Ser682 carbonyl to
Asn381 amide. (C) A closeup view of the interactions between the
strand of
SARA and the three-helix bundle and strand B1' of Smad2.