Biochemical analysis of the interactions of IQGAP1 C-terminal domain with CDC42

Table 1 Binding parameters for the interaction of IQGAP1(DR6) and CDC42

IQGAP1(DR6) variant	ka/l.mol-1.s-1	kd/s-1	KD/μmol/L
Wild type	4900 ± 100	(6.5 ± 0.5) × 10-3	1.3 ± 0.13
S1441E	12 ± 1	(2.7 ± 0.03) × 10-3	220 ± 21
S1443D	5800 ± 100	(4.7 ± 0.2) × 10-3	0.81 ± 0.048
S1441E/S1443D	3600 ± 100	(4.0 ± 0.2) × 10-3	1.1 ± 0.086
M1231I	1800 ± 100	(1.7 ± 0.2) × 10-3	0.90 ± 0.16

These were determined by surface plasmon resonance. The values are reported ± their standard errors as determined by the BIAevaluation fitting programme (see Materials and Methods).