title: An RNA replisome as the ancestor of the ribosome.
abstract: The ribosome is proposed to have evolved from an earlier RNA-replisome, which synthesized RNA. Ancestral tRNA molecules originally were loaded with trinucleotide sequences and donated them to growing RNA chains. The enzymatic addition of the C-C-A trinucleotide to presentday transfer RNA molecules is a carryover from this function. The strategies of reading RNA sequences by triplet codons and of housing information genetically in special repository molecules predates the origin of protein and DNA. These latter two polymers arose together at the time when the RNA replisome was converted to a ribosome.
authors.affiliation: Department of Anatomy and Cell Biology, School of Medicine, University of California, Los Angeles 90024.
authors.forename: J H
authors.initials: JH
authors.lastname: Campbell
mesh_terms: D001483:Base Sequence; D005075:Biological Evolution; D014176:Protein Biosynthesis; D012313:RNA / Q000096:biosynthesis*; D012270:Ribosomes / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D012313:RNA