B Cartoon model of human IDO1 (gray) and the SH2 domain of PI3K p85 (orange) complex as resulting from docking study. Residues of the YENM motif are colored in yellow and shown in sticks. Residues of phosphotyrosine binding site in p85 are colored in cyan and shown in sticks. Heme and l-tryptophan are shown in sticks and colored in red and green, respectively. 