title: The NH2-terminal domain of Escherichia coli ribosomal protein L11. Its three-dimensional location and its role in the binding of release factors 1 and 2.
abstract: Ribosomes from three previously described mutants of Escherichia coli lacking L11 ( AM68 , AM76 , and AM77 ) supported in vitro termination with release factor 1 very poorly, but with release factor 2 had a severalfold elevation in activity for this function compared with ribosomes from a control strain or from a mutant containing unmethylated L11. L11 exerts its effect on the binding of the factors into a functional ribosomal complex with the termination codon. Reconstitution of L11 back into the L11-lacking ribosomes restored them to the control phenotype. The NH2-terminal part of L11 (amino acids 1-64) seems critical in modulating release factor binding. This part of L11 has been localized with the use of fragment-specific antibodies on the three-dimensional model of the 50 S subunit in the region from where the L7/L12 stalk originates. IgG antibodies from an antiserum specific for this fragment but not a middle fragment of L11 (amino acids 65-102) strongly inhibited in vitro termination. The activities of the two factors were inhibited differentially by several anti-L11 preparations recognizing antigenic determinants in the NH2-terminal part of L11. In all but one case, release factor 1 was more sensitive. These studies indicate that there are significant differences in the binding domains for the two release factors which are affected by the NH2-terminal part of L11.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004926:Escherichia coli / Q000032:analysis*; D007074:Immunoglobulin G / Q000378:metabolism; D046911:Macromolecular Substances; D008854:Microscopy, Electron; D010454:Peptide Termination Factors / Q000378:metabolism*; D011817:Rabbits; D012269:Ribosomal Proteins / Q000032:analysis*; D012756:Sheep
chemical_list: D007074:Immunoglobulin G; D046911:Macromolecular Substances; D010454:Peptide Termination Factors; D012269:Ribosomal Proteins; C041460:peptide chain termination release factor 2; C027624:ribosomal protein L11