TABLE 1.

Kinetic parameters of Rickettsial methyltransferases

The steady state kinetics was monitored by the incorporation of radioactive [methyl-3H] from [methyl-3H]AdoMet into OmpB(AN) as described under “Materials and Methods.” The final concentration of methyltransferase was 0.26 μm.

Methyltransferase	KmAN	kcat	kcat/Km
	μm	s−1	m−1·s−1
RT0101	0.48 ± 0.057	0.83 × 10−3	1.74 × 103
RP027-028a	10.1 ± 1.63	0.16 × 10−3	0.015 × 103
RP789	0.29 ± 0.093	5.98 × 10−3	20.6 × 103
RP789ΔN	1.13 ± 0.17	3.32 × 10−3	2.93 × 103
RT0776	1.71 ± 0.182	2.20 × 10−3	1.28 × 103
RT0776ΔN	3.07 ± 1.55	4.45 × 10−3	1.45 × 103

^a RP027-028-catalyzed methylation was analyzed at 2 μm RP027-028 and 2–20 μm OmpB(AN) because of the low enzyme efficiency.