Table 1.

ITC derived apparent dissociation constants for each step of the TAPBPR-mediated peptide exchange cycle.

	TAPBPRWT	n value	TAPBPRΔG24-R36	n value
TAX8 KD1,app	37.4 nM	n/d	13.9 nM	n/d
TAX9 KD1,app	30.6 nM	n/d	11.1 nM	n/d
KLL15 KD1,app	38.8 nM	n/d	14.2 nM	n/d
TAX8 KD2,app	326 ± 14 nM	0.43 ± 0.02	316 ± 19 nM	0.44 ± 0.03
TAX9 KD2,app	40.2 ± 6.5 nM	0.42 ± 0.01	42.6 ± 8.3 nM	0.46 ± 0.01
KLL15 KD2,app	383 ± 22 nM	0.45 ± 0.06	334 ± 20 nM	0.41 ± 0.01
TAX8 KD3	2.6 ± 0.5 µM	1.00 ± 0.03	2.4 ± 0.6 µM	1.03 ± 0.01
TAX9 KD3	1.9 ± 0.7 µM	1.02 ± 0.01	1.8 ± 0.3 µM	1.06 ± 0.02
KLL15 KD3	2.2 ± 0.5 µM	1.05 ± 0.04	2.1 ± 0.3 µM	1.03 ± 0.01
TAX8 KD4	22.7 ± 8.2 µM	1.01 ± 0.02	54.4 ± 9.4 µM	1.05 ± 0.02
TAX9 KD4	2.5 ± 0.8 µM	1.04 ± 0.01	7.3 ± 0.7 µM	1.02 ± 0.02
KLL15 KD4	21.6 ± 7.0 µM	1.10 ± 0.05	49.5 ± 8.6 µM	1.03 ± 0.04

TAX8 = LFGYPVYV

TAX9 = LLFGYPVYV

KLL15 = KLLEIPDPDKNWATL

WT = wild-type

Due to experimental limitations, the measured K_D1 and K_D2 values are “apparent”, denoted with the use of “app”.

n/d not determined because the K_D1 value is calculated from thermodynamic balance, n value corresponds to observed stoichiometry by ITC.