|
Figure 6.
Figure 6. Binding of the Catalytic Subunit Reorganizes the
N3A Motif and the Phosphate-Binding Cassette in the Regulatory
Subunit to Create a Contiguous Hydrophobic Interface
(A)
Comparison of the helical regions in domain A between the cAMP
(left) and catalytic subunit-bound (right) conformations.
Movement of the helical regions is mediated by hydrophobic
rearrangement of the hinge residues in the PBC (Ile203^R and
Leu204^R), αB helix (Tyr229^R), and 3[10] loop (Leu135^R).
(B) Comparison of domain B in the cAMP and catalytic
subunit-bound conformations, highlighting the C-terminal tail
(red). In domain B, the helical rearrangements are similar to
domain A where residues in the PBC (Leu327^R and Leu328^R), αB
helix (Phe353^R), and 3[10] loop (Ile253^R and Leu254^R) come
together.
(C) Comparison between domains A and B in the
holoenzyme conformation. In domain A, the N3A motif (residues
123–150) and PBC come together and serve as a docking surface
for the P+1 loop (black) and the αG helix (dark tan) of the
catalytic subunit. In domain B, a similar hydrophobic interface
is formed between the N3A motif (residues 245–367) and PBC;
however, the C-terminal tail (αB, αC′, and αC″ helices)
lies on top of the hydrophobic interface.
|
