Table 2.

Base compositions of RNase digestion products that increased by 252 or 504 u after reaction with CMCT. Base compositions were determined using a mass accuracy of 0.05% or better. If the experimental m/z did not match a base composition with no modifications, the known modification masses of tRNA modified nucleosides were then used to identify probable base compositions.

RNase	Exp m/z	Base compositions	Matching tRNAs (in Table 1)	Matching tRNAs (not in Table 1)
A	1341.7	AG2Cp; AG2Up	GlnII, GlyII, His, LeuII, LeuIII, Phe, SerI, SerII, SerIII, SerIV, Trp	ArgI, ArgII, ArgIV, Asn, Asp, Cys, IleII, LeuI, ValI, ValII
A	1424.7	A3Up + 114 (ms2i6)	Phe, TyrI, TyrII	Cys, LeuI
A	1687.7	AG3Up	LeuIII, Phe SerI, SerII, SerIII, SerV, ThrI, ThrII	IleI, IleII, LeuI
A	2081.3	A5Up + 114 (ms2i6)	no match	no match
A	2098.4	A4GUp + 114 (ms2i6)	Phe	no match
A	2362.4	A2G4Up	Phe	no match
T1	1293.6	CU2Gp + 14 (methyl)	ArgIII, ArgV, GlnII, GluI, GluII, GluIII, GlyI, GlyII, His, Met, Phe, ArgIII, ArgV, SerII, SerIII, SerIV, SerV, ThrI, ThrII, Trp, TyrI, TyrII	AlaI, AlaII, AlaIII, ArgI, ArgII, ArgIV, Asn, Asp, Cys, GlnI, GlyIII, Lys, ValI, ValII, ValIII, Sec6
T1	1302.8	AU2Gp	ArgIII, His, Phe, LeuII, SerII, ThrII	AlaI, ArgIV, Cys, Lys, ValII
T1	2265.5	A3C2UGp	GlnII	no match
T1	2402.5	A4C2Gp + 114 (ms2i6)	SerI, SerV, Trp	no match
T1	3319.8	A4C4UGp + 114 (ms2i6);A4C3U2Gp + 114 (ms2i6)	Phe	no match