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Figure 2.
Figure 2. A surface representation of the B-box2 domain. (a)
The surface of the MID1 B-box2 domain showing basic patches
(colored blue) comprised of lysine and arginine residues, acidic
patches (colored red) of glutamic and aspartic acid residues,
and hydrophobic patches (colored green) formed by leucine,
isoleucine, alanine, tyrosine, methionine, and valine. All other
residues are white. Two spheres representing the two zinc atoms
and a ribbon drawing of B-box2 are depicted. Note the extensive
hydrophobic surface on the outer surface of the helix and
structured loop with the β-strands. This pattern of hydrophobic
surfaces and distinct charge patches is similar in the other
B-box2 domains, except TRIM29. (b) Hydrophobic and charge
distribution of TRIM29 B-box2, shown in the same orientation as
MID1 B-box2 in (a) (left). The other side of TRIM29 B-box2 (not
shown) is predominately hydrophobic. Notably, the surface above
the structured loop with the two β-strands is hydrophobic,
similar to MID1 B-box2; however, a C-terminal helix packs
against this surface, suggesting a possible domain–domain
interface. (c) The superposition of MID1 B-box1 (green) and
B-box2 (red) showing the overall similarity in secondary and
tertiary structures, even though their primary sequences are not
homologous. The relative locations of the zinc ions (shown as
green and red balls) are also similar.
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