Structural aspects of nucleotide ligand binding by a bacterial 2H phosphoesterase

Myllykoski, Matti; Kursula, Petri

The 2 0 -5 0 phosphodiester linkage between RNA nucleotides is apparently rare, but is nevertheless found all across biology. In animals, 2-5As synthesized by 2 0 -5 0 -oligoadenylate synthases 2H enzyme active site structure have functions in innate immunity, whereby they specifically activate RNase L [30] . RNase L then cleaves singe-stranded viral or cellular RNAs. 2-5As can also have antibacterial activity [31] . Some viruses produce an enzyme that degrades 2 0 -5 0 -linked oligoadenylates and prevents the activation of RNase L [13, 32] . 2 0 -5 0 oligoadenylates have also been detected in E. coli. The level of these oligoadenylates increased as a response to phage infection, similarly to animals [20] . Bacterial oligoadenylates are apparently adequate to activate RNase L, since the overexpression of recombinant mammalian nuclease resulted in RNA degradation and cell growth inhibition [33] . LigT might function in the metabolism of bacterial 2-5As [20] .