Multisite-specific tRNA:(cytosine-C5)-methyltransferase explained

Multisite-specific tRNA:(cytosine-C5)-methyltransferase
Ec Number:	2.1.1.202

Multisite-specific tRNA:(cytosine-C5)-methyltransferase (multisite-specific tRNA:m5C-methyltransferase, TRM4 (gene)) is an enzyme with systematic name S-adenosyl-L-methionine:tRNA (cytosine-C5)-methyltransferase.^{[1] [2] [3] [4]} This enzyme catalyses the following chemical reaction

(1) S-adenosyl-L-methionine + cytosine³⁴ in tRNA precursor

\rightleftharpoons S-adenosyl-L-homocysteine + 5-methylcytosine³⁴ in tRNA precursor

(2) S-adenosyl-L-methionine + cytosine⁴⁰ in tRNA precursor

\rightleftharpoons S-adenosyl-L-homocysteine + 5-methylcytosine⁴⁰ in tRNA precursor

(3) S-adenosyl-L-methionine + cytosine⁴⁸ in tRNA

\rightleftharpoons S-adenosyl-L-homocysteine + 5-methylcytosine⁴⁸ in tRNA

(4) S-adenosyl-L-methionine + cytosine⁴⁹ in tRNA

\rightleftharpoons S-adenosyl-L-homocysteine + 5-methylcytosine⁴⁹ in tRNA

The enzyme from Saccharomyces cerevisiae is responsible for complete 5-methylcytosine methylations of yeast tRNA.

Notes and References

1. Motorin Y, Grosjean H . Multisite-specific tRNA:m5C-methyltransferase (Trm4) in yeast Saccharomyces cerevisiae: identification of the gene and substrate specificity of the enzyme . RNA . 5 . 8 . 1105–18 . August 1999 . 10445884 . 1369833 . 10.1017/s1355838299982201 .
2. Jiang HQ, Motorin Y, Jin YX, Grosjean H . Pleiotropic effects of intron removal on base modification pattern of yeast tRNAPhe: an in vitro study . Nucleic Acids Research . 25 . 14 . 2694–701 . July 1997 . 9207014 . 146816 . 10.1093/nar/25.14.2694 .
3. Strobel MC, Abelson J . Effect of intron mutations on processing and function of Saccharomyces cerevisiae SUP53 tRNA in vitro and in vivo . Molecular and Cellular Biology . 6 . 7 . 2663–73 . July 1986 . 3537724 . 367823 . 10.1128/mcb.6.7.2663 .
4. Walbott H, Husson C, Auxilien S, Golinelli-Pimpaneau B . Cysteine of sequence motif VI is essential for nucleophilic catalysis by yeast tRNA m5C methyltransferase . RNA . 13 . 7 . 967–73 . July 2007 . 17475914 . 1894932 . 10.1261/rna.515707 .