Open AccessRole for the highly conserved region of domain IV of 23 S-1 ike rRNA in subunit-subunit interactions at the peptidyl transferase centre
Author(s) -
Ilia Leviev,
S Levieva,
Roger A. Garrett
Publication year - 1995
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/23.9.1512
Subject(s) - 23s ribosomal rna , peptidyl transferase , ribosome , biology , protein subunit , ribosomal rna , eukaryotic large ribosomal subunit , transferase , mutagenesis , eukaryotic ribosome , eukaryotic small ribosomal subunit , genetics , 50s , microbiology and biotechnology , conserved sequence , mutant , biochemistry , rna , peptide sequence , enzyme , gene
The function of the highly conserved and accessible region of domain IV of 23S rRNA (positions 1900-1981 in Escherichia coli 23S rRNA) was investigated by subjecting it to a random mutagenesis procedure that produced single-site mutations efficiently. Nine single-site mutants were selected that were recessive lethal. High levels of mutated 23S rRNA were expressed in E. coli and extracted ribosomes were investigated for their content of mutated rRNA. The peptidyl transferase activity of the ribosomes was also estimated using a newly developed method involving selective inhibition of chromosome-encoded ribosomes by clindamycin. Two of the mutants, U1940A and U1955G, yielded 50S subunits that were defective in subunit-subunit association but active in peptidyl transferase activity and five, U1926C, U1946C, U1979C, U1982A and G1984A, produced 50S subunits that were defective in both subunit-subunit interactions and peptidyl transferase activity. We infer that the large conserved rRNA region generates a complex structure that plays an essential role in maintaining and modulating subunit-subunit interactions and argue that its involvement in the peptidyl transferase centre is secondary, possibly involving the correct alignment of protein L2.