A) 1–10a (■) and 1–10d (■) show preference for the GACKIX N627C mutant located near the MLL-binding site. N644C is located in the loop and the remaining mutants, K662C, H651C, Q609C, and K606C, are located within the pKID-binding site. The error bars represent SD of the average of two separate experiments. B) The 1–10 chemical cochaperones were dosed into E. coli during the expression of GACKIX N627C and after nickel affinity purification; the extent of labeling was assessed by means of LC-MS. The error bars represent SD of the average of three values from separate experiments. *0.01<p<0.05, **0.05<p<0.001,***0.001<p<0.001, ****p<0.001; p values are calculated by using the GraphPad Prism 7.0 program.