Nomenclature of plasmid-mediated 16S rRNA
methylases responsible for panaminoglycoside resistance.
aureus synthesizes ribosomal
methylase, which is encoded by the erythromycin resistance gene or another
methylases (ERM).
However, its unique structure may serve in the future as a prototype for new molecules resistant to both NDM and
methylases [27].
Distribution of genes encoding erythromycin ribosomal
methylases and an erythromycin efflux pump in epidemiologically distinct groups of staphylococci.
In the first step of this cycle, the SAM-dependent
methylases that use SAM as a substrate produce S-adenosyl homocysteine as a product.
The resistance is via three related genes, ermA, ermB, and ermC, which produce
methylases that alter the targeted ribosome by methylating it.
Site-specific
methylases induce the SOS DNA repair response in Escherichia coli.
The activity of endogenous
methylases in human placenta increased steadily with weeks of gestation, suggesting that increased formation of methyltransferases might occur during pregnancy (Paik et al.
24,25) Secondly, high-level macrolide resistance may result from modification of the drug target (ribosomal binding site) via erm(B) genes that encode 23S rRNA
methylases, and lead to cross-resistance to the ML[S.
Like other
methylases, Dam chemically coats DNA with clusters of atoms known as methyl groups.
aureus is usually caused either by ribosomal modification mediated by 23S rRNA
methylases encoded by erm genes, or by active efflux of the antimicrobial agent by an ATP-dependent pump encoded by msrA gene.
In that study, ~2-5% of CCGG sites were fully methylated, suggesting that nuclear
methylases enter a subset of the mitochondria.
