Table 1.

Nucleotide binding to the NG domain of FtsY and comparison with other GTPases

Protein	Nucleotide	K1, M−1	k+2, s−1	k−2, s−1	Kd, M
NG FtsY	GDP (20°C)	2.15  × 104	119	3.7	2.14  × 10−6*
	GTP (20°C)	2.37  × 104	>200	35	10.7  × 10−6*
Ras-p21 (17)	GDP (25°C)	5.7  × 104	14.8	1.8  × 10−5	2.17  × 10−11
	GTP (25°C)	1.25  × 105	16.7	1.7  × 10−5	8.14  × 10−12
Ran (28)	GDP (25°C)			1.5  × 10−5	6  × 10−12
	GTP (25°C)			11  × 10−5	3.8  × 10−11
Ran/RCC1 (28)	GDP (25°C)			21.1	8.06  × 10−7
	GTP (25°C)			19

^*Measurements from equilibrium titrations.