Mutations in RNAs of both ribosomal subunits cause defects in translation termination.
Mutations in RNAs of both subunits of the Escherichia coli ribosome caused defects in catalysis of peptidyl-tRNA hydrolysis in a realistic in vitro termination system. Assaying the two codon-dependent cytoplasmic proteins that drive termination, RF1 and RF2, we observed large defects with RF2 but not with RF1, a result consistent with the in vivo properties of the mutants. Our study presents the first direct in vitro evidence demonstrating the involvement of RNAs from both the large and the small ribosomal subunits in catalysis of peptidyl-tRNA hydrolysis during termination of protein biosynthesis. The results and conclusions are of general significance since the rRNA nucleotides studied have been virtually universally conserved throughout evolution. Our findings suggest a novel role for rRNAs of both subunits as molecular transmitters of a signal for termination.
Arkov
A L
AL
Department of Molecular Genetics (Box 11), The University of Texas M. D.Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Freistroffer
D V
DV
Ehrenberg
M
M
Murgola
E J
EJ
D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D006868:Hydrolysis; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010443:Peptide Chain Termination, Translational / Q000235:genetics*; D010454:Peptide Termination Factors / Q000378:metabolism; D017354:Point Mutation / Q000235:genetics*; D012336:RNA, Ribosomal, 16S / Q000737:chemistry / Q000235:genetics*; D012338:RNA, Ribosomal, 23S / Q000737:chemistry / Q000235:genetics*; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism
D029968:Escherichia coli Proteins; D010454:Peptide Termination Factors; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S; D012346:RNA, Transfer, Amino Acyl; C041460:peptide chain termination release factor 2; C489005:prfA protein, E coli; C489006:prfB protein, E coli; C019037:tRNA, peptidyl-