Figure 5.

X-ray diffraction structure of the C2(C771A)–PI(3,4,5)P₃ complex. Shown are three views of the complex (Protein Data Bank code 6FJC) in which rotation of view A about the vertical axis through ∼90° gives view B. PI(3,4,5)P₃ binds to chain A of an antiparallel C2(C771A) dimer as does PI(4,5)P₂. C, a closer view of the C2(C771A)–PI(3,4,5)P₃ interaction in the same orientation as A with electron density obtained in a simulated annealing omit map around the PI(3,4,5)P₃-binding site shown in blue mesh, contoured at 1.1σ. PI(3,4,5)P₃ is shown mainly in magenta. Some of the C2 residues that interact with PI(3,4,5)P₃ are shown (hydrophobic residues in yellow, polar residues in cyan, and positively charged residues in blue), including the side chains of Leu-678, Gln-681, Asn-727, and Arg-776 and backbone of Leu-666 and Ile-677. Oxygen and nitrogen atoms are shown in red and dark blue, respectively.