Fig. 10.10 The NMR spectroscopic structure of the BCL-XL protein with the α-helical, 16-membered peptide fragment from the BK protein (orange). The peptide binds in a deep groove with the amino acids Ile85, Ile81, Leu78, Val74 (from left to right, side chains are in light blue). The surface of the BCL protein is shown in white, the contact surface of the hydrophobic amino acids of the peptide all protrude into the cleft and are indicated by the light-blue net.