MAASGKLSTCRLPPLPTIREIIKLLRLQAAKQLSQNFLLDLRLTDKIVRKAGNLTNAYVYEVGPGPGGITRSILNADVAELLVVEKDTRFIPGLQMLSDAAPGKLRIVHGDVLTFKVEKAFSESLKRPWEDDPPNVHIIGNLPFSVSTPLIIKWLENISCRDGPFVYGRTQMTLTFQKEVAERLAANTGSKQRSRLSVMAQYLCNVRHIFTIPGQAFVPKPEVDVGVVHFTPLIQPKIEQPFKLVEKVVQNVFQFRRKYCHRGLRMLFPEAQRLESTGRLLELADIDPTLRPRQLSISHFKSLCDVYRKMCDEDPQLFAYNFREELKRRKSKNEEKEEDDAENYRL
h-mtTFB1 was first decribed as a nuclear-encoded mitochondrial transcription factor, but this protein has a dual function: acts as a mitochondrial transcription factor and an rRNA-modification enzyme. It methylates a conserved tandem A's (positions 1518, 1519, E. coli numbering) in the loop of a hairpin near the 3'-end of bacterial small subunit rRNA (as bacterial RsmA, formely KsgA). It was shown that the homologous sequence in the human mitochondrial 12S molecule is similarly modified. A second h-mtTFB2 also exists that is less efficient at methylating rRNA than h-mtTFB1. AdoMet is probably the methyl group donor. The structure of probable human cytosolic dimethyladenosine transferase has been solved (PDB id: 1ZQ9)
| _PubMed_ |