rRNA binding domain of yeast ribosomal protein L25. Identification of its borders and a key leucine residue.

摘要: Abstract We have delineated the region of yeast ribosomal protein L25 responsible for its specific binding to 26 S rRNA by a novel approach using in vitro synthesized, [ 35 S]methionine-labeled fragments as well point mutants protein. The capacity these mutant polypeptides was tested incubation with an transcribed, biotinylated fragment that contains complete site. Protein—rRNA interaction assayed rRNA—r-protein complex streptavidin-agarose followed either analysis bound polypeptide SDS/polyacrylamide gel electrophoresis or precipitation trichloroacetic acid. Our results show structural elements necessary and sufficient are contained bordered amino acids 62 126. remaining parts protein, particular C-terminal 16 residues, while not essential binding, do enhance affinity rRNA. To test whether, suggested deletion experiments, evolutionarily conserved sequence motif K 120 KAYVRL 126 is involved we replaced leucine residue at position isoleucine lysine. first substitution did affect binding. second, however, completely abolished Thus, Leu126, possibly whole motif, plays key role