TABLE 1.

Content of modified nucleosides in tRNA^Glu_mcm⁵s²UUC , tRNA^Arg_mcm⁵UCU , and tRNA^Pro_ncm⁵UGG isolated from elp1–elp6 and kti11–kti13 mutants

tRNA species	Modified nucleoside	SUP4	elp1Δa	elp2Δ	elp3Δ	elp3-Y540A	elp3-Y541A	elp3Δ/pELP3	elp4Δ	elp5Δ	elp6Δ	kti11Δ	kti12Δ	kti13Δ
tRNAGlumcm5s2UUC	Ψ	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00
	m5C	1.00	0.89	0.94	0.71	0.79	0.92	0.67	0.92	1.01	0.89	0.79	0.82	0.83
	m5U	1.00	0.99	1.01	0.95	0.96	1.00	0.81	1.00	1.00	0.94	0.89	0.99	0.96
	s2U	−c	+d	+	+	+	+	−	+	+	+	+	+	+
	mcm5s2U	1.00	<0.09b	<0.07	<0.02	<0.05	0.13	1.22	<0.07	<0.03	<0.04	<0.05	<0.06	0.18
tRNAArgmcm5UCU	Ψ	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00
	m1A	1.00	0.93	0.90	1.24	1.20	1.17	1.12	0.89	1.14	1.04	1.03	0.85	0.85
	m5U	1.00	1.00	0.98	1.01	1.07	1.05	1.09	1.00	1.05	1.03	1.04	0.98	1.02
	m1G	1.00	1.04	1.08	1.07	0.88	0.96	0.79	1.04	0.94	0.98	0.90	1.10	1.04
	m2G	1.00	1.04	1.08	1.10	0.87	0.97	0.79	1.05	0.87	0.94	0.88	1.11	1.04
	m22G	1.00	1.05	1.09	1.09	0.88	0.97	0.79	1.06	0.88	0.95	0.89	1.11	1.05
	t6A	1.00	1.05	1.05	1.29	1.11	1.12	1.11	1.14	0.85	0.98	1.04	1.14	1.14
	mcm5U	1.00	<0.05b	<0.04	<0.01	<0.04	0.12	0.78	<0.05	<0.04	<0.04	<0.05	<0.05	0.15
tRNAProncm5UGG	Ψ	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00
	m1A+m5Ce	1.00	1.01	0.98	0.96	0.96	0.91	1.07	0.99	0.99	1.00	1.04	0.98	1.05
	Cm	1.00	0.93	0.95	1.03	0.83	0.87	0.67	0.91	0.94	0.93	0.77	0.99	0.95
	m5U+m7Gf	1.00	1.09	1.03	1.02	1.01	0.94	1.10	1.03	1.05	1.04	1.15	1.01	1.07
	m1G	1.00	0.94	0.92	0.90	0.92	0.89	0.96	0.93	1.01	0.98	0.89	0.96	1.00
	ncm5U	1.00	<0.03b	<0.05	<0.03	<0.04	<0.03	0.60	<0.04	<0.04	<0.04	<0.04	<0.04	0.16

Pseudouridine (Ψ), present three times in tRNA^Glu_mcm⁵s²UUC , three times in tRNA^Arg_mcm⁵UCU , and four times in tRNA^Pro_ncm⁵UGG , was used as the internal standard. The numbers given are the ratios of the various modified nucleosides (modified nucleoside/Ψ) in respective tRNA isolated from the SUP4, SUP4 elp, or SUP4 kti mutants normalized to the ratio in the SUP4 strain. Nucleosides s²U, mcm⁵s²U, mcm⁵U and ncm⁵U are shown in bold.

^aDeletion with a KanMX cassette.

^bDetection limit.

^cNo detection of s²U.

^dPresence of s²U.

^em¹A comigrated with m⁵C.

^fm⁵U comigrated with m⁷G.

Abbreviations: (Ψ) pseudouridine; (m⁵C) 5-methylcytidine; (m⁵U) 5-methyluridine; (s²C) 2-thiouridine; (mcm⁵s²U) 5-methoxycarbonylmethyl-2-thiouridine; (m¹A) 1-methyladenosine; (m¹G) 1-methylguanosine; (m²G) N²-methylguanosine; (m²₂G) N², N²-dimethylguanosine; (t⁶A) N⁶-threonylcarbamoyladenosine; (mcm⁵U) 5-methoxycarbonylmethyluridine; (Cm) 2′-O-methylcytidine; (m⁷G) 7-methylguanosine; and (ncm⁵U) 5-carbamoylmethyluridine.