Modified nucleotides in Bacillus subtilis tRNATrp hyperexpressed in Escherichia coli

• Published in: Nucleic acids research 1993-05, Vol.21 (10), p.2479-2486
• Main Authors: Xue, Hong, Glasser, Anne-Lise, Desgres, Jean, Grosjean, Henri
• Format: Article
• Language: English
• Subjects: Bacteriology; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Genetics; Microbiology
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/21.10.2479

In the present study, modified nucleotides in the B.subtilis tRNATrp cloned and hyperexpressed In E.coll have been identified by TLC and HPLC analyses. The modification patterns of the two isoacceptors of cloned B.subtilis tRNATrp have been compared with those of native tRNATrp from B.subtilis and from E.coll. The modifications of the A73 mutant of B.subtllls tRNATrp, which is inactive toward Its cognate TrpRS, were also Investigated. The results indicate the formation of the modified nucleotides s4U8, Gm18, D20, Cm32, l6A/ms2i6A37, T54 and ψ55 on cloned B.subtllls tRNATrp. This modification pattern resembles the pattern of E.coll tRNATrp, except that m7G is missing from the cloned tRNATrP, probably on account of Its short extra loop. In contrast, the pattern departs substantially from that of native B.subtllls tRNATrP. Therefore, the cloned B.subtllls tRNATrp has taken on largely the modification pattern of E.coll tRNATrp despite the 26% sequence difference between the two species of tRNA, gaining In particular the Cm32 and Gm18 modifications from the E.coll host. A notable difference between the isoacceptors of the cloned tRNATrp was seen in the extent of modification of A37, which occurred as either the hypomodlfied l6A or the hypermodified ms2l6A form. Surprisingly, base substitution of guanoslne by adenoslne at position 73 of the cloned tRNATrp has led to the abolision of the 2'-O-methylation modification of the remote G18 residue.