Figure 3 - full size

 

Figure 3.
FIG. 3. Conformational differences in the ATP-binding site of Btk (cyan ribbons and cyan side chains) and Itk (green ribbons and green side chains). Unphosphorylated and phosphorylated Itk adopts a closed catalytic conformation of the C-helix and glycine-rich loop. In contrast, the glycine-rich loop of unphosphorylated Btk blocks the ATP-binding site, which is not consistent with inhibitor binding. The Itk gatekeeper residue, Phe^435, and catalytically important residues are shown in detail. Itk residue numbering is used unless specified.

The above figure is reprinted by permission from the ASBMB: J Biol Chem (2004, 279, 18727-18732) copyright 2004.