TABLE 3.

2-Methylthio (ms²) modification levels in tRNA isolated from mutant strains^a

Mutant locus	yggX deficient		yggX+
	i6A	ms2i6A + ms2io6A	i6A	ms2i6A + ms2io6A
WT	0.14 ± 0.03	0.86 ± 0.04	<0.05	>0.95
isc1	>0.95	<0.05	>0.95	<0.05
iscA	>0.95	<0.05	>0.95	<0.05
apbC	0.17 ± 0.03	0.83 ± 0.03	<0.05	>0.95
apbE	0.69 ± 0.06	0.31 ± 0.06	0.45 ± 0.03	0.55 ± 0.03
rseC	0.59 ± 0.01	0.41 ± 0.01	0.33 ± 0.04	0.67 ± 0.04
gshA	0.69 ± 0.02	0.31 ± 0.02	<0.05	>0.95

^aValues were derived from high-performance liquid chromatography peak areas and are represented as the fraction of total i⁶ A-derived species (i⁶A + ms²i⁶A + ms²io⁶A). Errors represent deviations for duplicate experiments. The position of MiaB in the biosynthetic pathway is shown in Fig. 2.