Figure 5. A model structure of the CD28-derived peptide bound to PI3K N.

(A) The crystal structure of the amino-terminal SH2 domain of PI3K (PI3K N SH2) with a phosphopeptide derived from c-Kit (T-N-E-pY-M-D-M-K) and (B) a molecular model of PI3K N SH2 with the CD28-derived peptide (S-D-pY-M-N-M-T). The SH2 domains are shown as surface models, whereas the phosphopeptides are shown as stick models.