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Figure 2.
Figure 2. Crystal Structure of the APS(SH2)-IRK
ComplexRibbon diagram (top) and all-atom representation (bottom)
of the APS(SH2)-IRK structure. The noncrystallographic 2-fold
axis is vertical. The two IRK molecules are colored cyan, except
for the activation loop, which is colored yellow. The two
APS(SH2) protomers are colored green and purple. The three
phosphotyrosine residues in the IRK activation loop are shown in
ball-and-stick representation, with carbon atoms colored yellow,
oxygen atoms colored red, and phosphorus atoms colored
black. The bisubstrate inhibitor is colored orange, with the
peptide portion shown in ribbon/coil representation, and the
substrate tyrosine, linker, and ATPĪ³S atoms shown in
ball-and-stick representation. The N termini of the IRK
molecules, which lead into the juxtamembrane region (34 residues
to the transmembrane helix), are indicated, as are the C termini
of the APS(SH2) protomers. The C-terminal tyrosine
phosphorylation site in APS (Tyr-618) is 132 residues from the
end of the SH2 domain.
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