EC - 16S rRNA (adenine1518-N6/adenine1519-N6)-dimethyltransferase

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IntEnz Enzyme Nomenclature


Accepted name:
16S rRNA (adenine1518-N6/adenine1519-N6)-dimethyltransferase
Other names:
S-adenosylmethionine-6-N',N'-adenosyl (rRNA) dimethyltransferase
ksgA methyltransferase
Systematic name:
S-adenosyl-L-methionine:16S rRNA (adenine1518-N6/adenine1519-N6)-dimethyltransferase



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

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0052908
UniProtKB/Swiss-Prot: (624) [show] [UniProt]


  1. Helser, T. L., Davies, J. E., Dahlberg, J. E.
    Change in methylation of 16S ribosomal RNA associated with mutation to kasugamycin resistance in Escherichia coli.
    Nature New Biol. 233: 12-14 (1971). [PMID: 4329247]
  2. Helser, T. L., Davies, J. E., Dahlberg, J. E.
    Mechanism of kasugamycin resistance in Escherichia coli.
    Nature New Biol. 235: 6-9 (1972). [PMID: 4336392]
  3. van Buul, C. P., 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: 65-72 (1985). [PMID: 3905517]
  4. Formenoy, L. J., Cunningham, P. R., Nurse, K., Pleij, C. W., 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: 1123-1128 (1994). [PMID: 7538324]
  5. O'Farrell, H. C., Scarsdale, J. N., Rife, J. P.
    Crystal structure of KsgA, a universally conserved rRNA adenine dimethyltransferase in Escherichia coli.
    J. Mol. Biol. 339: 337-353 (2004). [PMID: 15136037]
  6. Poldermans, B., Roza, L., 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: 9094-9100 (1979). [PMID: 383712]
  7. Demirci, H., Belardinelli, R., Seri, E., Gregory, S. T., Gualerzi, C., Dahlberg, A. E., 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: 271-282 (2009). [PMID: 19285505]
  8. Tu, C., Tropea, J. E., Austin, B. P., Court, D. L., Waugh, D. S., Ji, X.
    Structural basis for binding of RNA and cofactor by a KsgA methyltransferase.
    Structure 17: 374-385 (2009). [PMID: 19278652]

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