Sprecher
Beschreibung
Modified nucleotides expand the structural and functional diversity of RNA, and many of them are highly conserved throughout evolution. Nucleobase methylation is the smallest modification installed by specialized enzymes that use nucleotide cofactors such as S-adenosylmethionine, which may be considered as “evolutionary leftovers” from an RNA world. We speculate that methylated nucleotides could have influenced the evolutionary path of catalytic RNA. Ribozymes may have installed modifications to enhance catalysis or mediate their removal to facilitate replication and storage of genetic information. Using in vitro evolution, we found a modern analogue of such a ribozyme that catalyses the site-specific methyl transfer reaction from a cofactor to RNA. We studied the structure of the methyltransferase ribozyme together with the methylated RNA and report insights into cofactor binding site and catalytic mechanism.
