title: The role of the basic N-terminal region of protein L18 in 5S RNA-23S RNA complex formation.
abstract: Of the three proteins, L5, L18 and L25, which bind to 5S RNA, the former two effect the interaction of 5S RNA with 23S RNA. We have used trypsin as a probe to investigate the roles of the proteins in this RNA-RNA assembly, with the following results: (1) In complexes with 5S RNA, the highly basic N-terminal region of L18 is accessible to trypsin. This accessibility is unaffected by L25. However, its presence is essential for stimulating L5 binding. (2) In 5S RNA-protein-23S RNA complexes proteins L5 and L18 are both strongly resistant to proteolysis. (3) No 5S RNA-23S RNA complex formation occurs in the presence of L5 and the C-terminal L18 fragment. Two possible models for the mechanism of RNA-RNA assembly are proposed.
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis*; D004926:Escherichia coli / Q000032:analysis*; D046911:Macromolecular Substances; D008970:Molecular Weight; D009698:Nucleoproteins / Q000032:analysis*; D011485:Protein Binding; D012329:RNA, Bacterial / Q000032:analysis*; D012261:Ribonucleoproteins / Q000032:analysis*; D014357:Trypsin
chemical_list: D001426:Bacterial Proteins; D046911:Macromolecular Substances; D009698:Nucleoproteins; D012329:RNA, Bacterial; D012261:Ribonucleoproteins; D014357:Trypsin