We expressed, produced and purified the WT and mutants of the bovine PI3K-SH3 domain according to a previously published protocol . All constructs contain a 6xHistag linked to protein with a thrombin cleavage site. All proteins were expressed in BL21 E. coli with Terrific Broth Medium with 0.012 % Glucose and 0.048 % Lactose for auto induction. Cells were grown for 24 hrs and harvested by centrifuging at 5000 G for 30 min. The cells were re-suspended in sodium phosphate buffer (50 mM sodium phosphate,