title: Recognition of individual procaryotic and eucaryotic transfer-ribonucleic acids by B subtilis adenine-1-methyltransferase specific for the dihydrouridine loop.
abstract: Bulk tRNA from yeast and Rat liver can be methylated in vitro with -adenosylmethionine and B, subtilis extracts. The sole product formed is 1-methyladenosine (m1A). This tRNA (adenine-1) methyltransferase converts quantitatively the 3'-terminal adenosine-residue in the dihydrouridine-loop of tRNAThr and tRNATyr from yeast into m1A. Out of 16 eucaryotic tRNAs with known sequences 6 accepted methyl groups, all at a molar ratio of 1. These tRNAs have in common an unpaired adenosine-residue at the specific site in the sequence Py-A-A+-G-G-C-m2G. Out of 12 tRNAs from E. coli 6 served as specific substrates. These E. coli tRNAs also have an unpaired adenosine-residue at the 3'-end of the D-loop. Besides restrictions in primary structure intact secondary and tertiary structure is important for recognition of the specific tRNAs by the enzyme.
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology*; D001483:Base Sequence; D005057:Eukaryotic Cells; D008745:Methylation; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D011387:Prokaryotic Cells; D012343:RNA, Transfer / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D012359:tRNA Methyltransferases / Q000378:metabolism*
chemical_list: D012343:RNA, Transfer; D012359:tRNA Methyltransferases