Table I. m¹G37 levels in tRNA and growth deficiency of S.typhimurium trmD mutants.

trmD alleles	trmD+	trmD23	trmD27/31	trmD30	trmD28	trmD25	trmD26	trmD3/24	trmD33	trmD29	trmD32
Amino acid substitution		P58L/L94F	S88L	G117S	G117N	G117Q	S165L	P184L	G199R	G214D	W217D
m1G/Ψa	0.12	0.006	<0.005	0.005	<0.005	0.014	0.005	0.047	0.006	<0.005	0.040b
Relative colony size atc
22°C	1 (1.4 mm)d	No col.e	0.3	0.6	No col.e	1.1	–e	1.1	<0.1	1.1	–e
30°C	1 (3 mm)d	0.4	0.7	0.7	0.2	0.8	<0.1	0.8	0.5	0.9	<0.1
37°C	1 (1.8 mm)d	0.4	0.7	0.6	<0.1	0.7	0.1	0.9	0.4	0.1–0.7	<0.1
42.5°C	1 (2.2 mm)d	<0.1	<0.1	0.3	No col.e	0.4	0.4	0.5	0.3	<0.1	0.2–0.4
44°C	1 (2.5 mm)d	No col.e	No col.e	0.2	No col.e	0.3	0.3	0.3	0.1	<0.1	0.3

^aThe level of m¹G was determined by HPLC in bulk tRNA prepared from cells grown in a rich medium (LB) at 37°C and is expressed as the absorbance of m¹G relative to that of pseudouridine (Ψ) at 254 nm.

^bThis level is overestimated, since Gm was trailing into the region where m¹G migrated.

^cThe growth of the various mutants at the indicated temperatures was determined by single-cell outstreak on TYS plates. The relative colony size was determined as the average size of ∼5 colonies in relation to the size of the wild type. Thus, <0.1 indicates that the growth of the mutant was <10% of that of the wild type.

^dAt 22 and 30°C, the diameters of the colonies were scored after 48 h and the sizes of the wild-type colonies were 1.4 and 3 mm, respectively. At 37, 42.5 and 44°C, the colony sizes were scored after 24 h and the sizes of wild-type colonies were 1.8, 2.2 and 2.5 mm, respectively.

^eNo col. denotes that only weak growth at the primary streak was observed and no individual colonies were visible. – denotes no growth. Bold denotes severe impairment of growth compared with the wild type.