Table 2.

Characterization of the tRNA MTase activity of _PabTrmI, H78Y_PabTrmI and _TtTrmI using different P. abyssi tRNAs^a

	[α-32P] labeled nucleotide used for production of tRNA transcript	Nuclease	Position of methylation tested	mole of m1A per tRNA
				TtTrmI	PabTrmI	H78YPabTrmI
PabtRNAAsp	ATP	P1	all A	0.85 ± 0.05	1.78 ± 0.19	0.9 ± 0.05
	UTP	T2	A59	0	0	0
A59G PabtRNAAsp	ATP	P1	all A	0.8 ± 0.05	1.05 ± 0.05	0.85 ± 0.05
	ATP	T2	A57	<1%	0.85 ± 0.15	0.70 ± 0.10
	GTP	T2	A58	0.7 ± 0.15	<5%	<1%

^aRadiolabeled tRNA transcripts were incubated in the presence of enzyme, then digested by nucleases P1 or T2 to test the methylation of adenine at positions 57, 58 and 59. The resulting nucleotides were analyzed by 2D–TLC on cellulose plates and autoradiography (Supplementary Figure S3).