Table 3.

Influence of phospholipid composition on the binding affinities of DOG for wild-type and δC1b mutants.

Receptor (PKCδ Clb)	Ki (nM) on l0% PS	Relative to l00% PS	Ki (nM) on 30% PS	Relative to l00% PS	Ki (nM) on l00% PS	No. of positive charges
K26Y	213 ±31	2 x	67.9 ± 1.3	0.64 x	106 ± 25	0
WT	63.3 ± 16.3	12 x	11.1 ± 1.7	2.1 x	5.3 ± 0.6	1
Sl0R	62.7 ± 4.9	17 x	12.5 ± 1.0	3.4 x	3.7 ± 0.9	2
N7R	791 ± 80	36 x	55.2 ± 4.8	2.5 x	21.8 ± 0.7	2
W22R	11873 ± 2754	169 x	470 ± 74	6.7 x	70.1 ±15.9	2
S10RW22R	3113 ± 948	133 x	126 ±18	5.5 x	23.4 ± 2.9	3
N7RW22R	20432 ± 3133	11 x	983 ± 64	0.5 x	1807 ± 103	3

The binding affinities of DOG to purified wild-type and mutant GST-PKCδ C1b domains were measured in the presence of the indicated proportions of PS in PS/PC phospholipid mixtures at a fixed total phospholipid concentration of 100 μg/ml. The K_i value relative to that in 100% PS is displayed. The number of positive charges in the binding cleft of each mutant is also shown. Values shown are the means ± SEM for n = 3 experiments.