Table 3.

ATP binding of the Rho mutants

Rho mutants	Kd, app (μM)
WT	0.54 ± 0.06
	(11.7 ± 2.2)
G51V	1.35 ± 0.26
Y80C	No cross-linking
	(43.2 ± 0.8)
Y274D	3.15 ± 0.26
P279S	4.28 ± 0.54
G324D	2.45 ± 0.15
N340S	1.09 ± 0.12
I382N	0.60 ± 0.1

Apparent dissociation constant (K_d,app) of ATP was determined by UV-cross-linking. The intensities of the cross-linked species were plotted against increasing concentrations of [γ-³²P]ATP and K_d values were obtained from the hyperbolic fitting of the plots. For Y80C, no cross-linking was observed up to 30 μM [γ-³²P]ATP. K_m values of ATP for WT and Y80C are shown in parenthesis. The concentration of WT and mutant Rho was 50 nM in hexamer.