IUBMB Enzyme Nomenclature


Accepted name: 16S rRNA (adenine1518-N6/adenine1519-N6)-dimethyltransferase

Reaction: 4 S-adenosyl-L-methionine + adenine1518/adenine1519 in 16S rRNA = 4 S-adenosyl-L-homocysteine + N6-dimethyladenine1518/N6-dimethyladenine1519 in 16S rRNA

Other name(s): S-adenosylmethionine-6-N',N'-adenosyl (rRNA) dimethyltransferase; KsgA; ksgA methyltransferase

Systematic name: S-adenosyl-L-methionine:16S rRNA (adenine1518-N6/adenine1519-N6)-dimethyltransferase

Comments: KsgA introduces the most highly conserved ribosomal RNA modification, the dimethylation of adenine1518 and adenine1519 in 16S rRNA. Strains lacking the methylase are resistant to kasugamycin [1].

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:


1. Helser, T.L., Davies, J.E. and Dahlberg, J.E. Change in methylation of 16S ribosomal RNA associated with mutation to kasugamycin resistance in Escherichia coli. Nat. New Biol. 233 (1971) 12-14. [PMID: 4329247]

2. Helser, T.L., Davies, J.E. and Dahlberg, J.E. Mechanism of kasugamycin resistance in Escherichia coli. Nat. New Biol. 235 (1972) 6-9. [PMID: 4336392]

3. van Buul, C.P. and van Knippenberg, P.H. Nucleotide sequence of the ksgA gene of Escherichia coli: comparison of methyltransferases effecting dimethylation of adenosine in ribosomal RNA. Gene 38 (1985) 65-72. [PMID: 3905517]

4. Formenoy, L.J., Cunningham, P.R., Nurse, K., Pleij, C.W. and Ofengand, J. Methylation of the conserved A1518-A1519 in Escherichia coli 16S ribosomal RNA by the ksgA methyltransferase is influenced by methylations around the similarly conserved U1512.G1523 base pair in the 3' terminal hairpin. Biochimie 76 (1994) 1123-1128. [PMID: 7538324]

5. O'Farrell, H.C., Scarsdale, J.N. and Rife, J.P. Crystal structure of KsgA, a universally conserved rRNA adenine dimethyltransferase in Escherichia coli. J. Mol. Biol. 339 (2004) 337-353. [PMID: 15136037]

6. Poldermans, B., Roza, L. and Van Knippenberg, P.H. Studies on the function of two adjacent N6,N6-dimethyladenosines near the 3' end of 16 S ribosomal RNA of Escherichia coli. III. Purification and properties of the methylating enzyme and methylase-30 S interactions. J. Biol. Chem. 254 (1979) 9094-9100. [PMID: 383712]

7. Demirci, H., Belardinelli, R., Seri, E., Gregory, S.T., Gualerzi, C., Dahlberg, A.E. and Jogl, G. Structural rearrangements in the active site of the Thermus thermophilus 16S rRNA methyltransferase KsgA in a binary complex with 5'-methylthioadenosine. J. Mol. Biol. 388 (2009) 271-282. [PMID: 19285505]

8. Tu, C., Tropea, J.E., Austin, B.P., Court, D.L., Waugh, D.S. and Ji, X. Structural basis for binding of RNA and cofactor by a KsgA methyltransferase. Structure 17 (2009) 374-385. [PMID: 19278652]

[EC created 1976 as EC, part transferred 2010 to EC]

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