PTHR11727

DIMETHYLADENOSINE TRANSFERASE

PANTHER entry
Member databasePANTHER
PANTHER typefamily

Description
Imported from IPR001737

The bacterial enzyme KsgA catalyses the transfer of a total of four methyl groups from S-adenosyl-l-methionine (S-AdoMet) to two adjacent adenosine bases in 16S rRNA. This enzyme and the resulting modified adenosine bases appear to be conserved in all species of eubacteria, eukaryotes, and archaea, and in eukaryotic organelles. Bacterial resistance to the aminoglycoside antibiotic kasugamycin involves inactivation of KsgA and resulting loss of the dimethylations, with modest consequences to the overall fitness of the organism
[1, 3, 2]
. In contrast, the yeast ortholog, Dim1, is essential. In Saccharomyces cerevisiae (Baker's yeast), and presumably in other eukaryotes, the enzyme performs a vital role in pre-rRNA processing in addition to its methylating activity
[5]
. Another orthologue is the eukaryotic transcription factor B (TFB), which has a second function; this enzyme is a nuclear-encoded mitochondrial transcription factor and is essential for mitochondrial gene expression
[4]
. The best conserved region in these enzymes is located in the N-terminal section and corresponds to a region that is probably involved in S-adenosyl methionine (SAM) binding domain.

rRNA adenine N-6-methyltransferases Erm methylate a single adenosine base in 23S rRNA. They confer resistance to the MLS-B group of antibiotics
[7, 6]
. Despite their sequence similarity to KsgA, the two enzyme families have strikingly different levels of regulation that remain to be elucidated.

References
Imported from IPR001737

1.Change in methylation of 16S ribosomal RNA associated with mutation to kasugamycin resistance in Escherichia coli. Helser TL, Davies JE, Dahlberg JE. Nat New Biol 233, 12-4, (1971). PMID: 4329247

2.Kasugamycin resistant mutants of Bacillus stearothermophilus lacking the enzyme for the methylation of two adjacent adenosines in 16S ribosomal RNA. Van Buul CP, Damm JB, Van Knippenberg PH. Mol Gen Genet 189, 475-8, (1983). PMID: 6575236

3.Mechanism of kasugamycin resistance in Escherichia coli. Helser TL, Davies JE, Dahlberg JE. Nat New Biol 235, 6-9, (1972). PMID: 4336392

4.Structural basis for S-adenosylmethionine binding and methyltransferase activity by mitochondrial transcription factor B1. Guja KE, Venkataraman K, Yakubovskaya E, Shi H, Mejia E, Hambardjieva E, Karzai AW, Garcia-Diaz M. Nucleic Acids Res. 41, 7947-59, (2013). View articlePMID: 23804760

5.Crystal structure of KsgA, a universally conserved rRNA adenine dimethyltransferase in Escherichia coli. O'Farrell HC, Scarsdale JN, Rife JP. J. Mol. Biol. 339, 337-53, (2004). View articlePMID: 15136037

6.Solution structure of an rRNA methyltransferase (ErmAM) that confers macrolide-lincosamide-streptogramin antibiotic resistance. Yu L, Petros AM, Schnuchel A, Zhong P, Severin JM, Walter K, Holzman TF, Fesik SW. Nat. Struct. Biol. 4, 483-9, (1997). View articlePMID: 9187657

7.The 2.2 A structure of the rRNA methyltransferase ErmC' and its complexes with cofactor and cofactor analogs: implications for the reaction mechanism. Schluckebier G, Zhong P, Stewart KD, Kavanaugh TJ, Abad-Zapatero C. J. Mol. Biol. 289, 277-91, (1999). View articlePMID: 10366505

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