Nucleic Acids Research, 1975, Vol. 2, No. 4 501-507
© 1975
Articles |
Modification of E. coli ribosomes and coliphage MS2 RNA by bisulfite: effects on ribosomal binding and protein synthesis
Department of Chemistry, New York University New York, NY 10003 and Department of Biochemistry, New York Universiiy School of Medicine New York, NY 10016, USA
Received January 30, 1975. The reaction of E. coli 70S ribosomes with 0.2 M NaH35S03 (pH 7.1, 3.5 hrs, 37°) led to the conversion of 4.5% of the uracil residues of the rRNA into 5,6-dihydrouracil-6-sulfonate residues. The modified ribosomes exhibited a significant decrease in their ability to bind [14C]-phenylalanyl-tRNA and to incorporate [14C]-phenylalanine into protein in the presence of polyuridylic acid. The ability of the modified ribosomes to form an initiation complex as measurecLby the A-U-G or coliphage MS2 RNA dependent binding of [14C]-fMet-tRNAfMet was also impaired, as was their ability to incorporate [14C]-lysine into protein with MS2 RNA as messenger. Treatment of MS2 RNA with 0.2 M sodium [35S] bisulfite, PH 7.0 at 25° C resulted in the substitution of 2.7% and 6.2% of the uracil residues by bisulfite after 1 and 3.5 hrs of reaction, respectively. Impairment of functianof the MS2 RNA in both iniation complex formation and translation assays was observed. These reactions of the uracil residues of mRNA and rRNA may be a cause of biological damage inflicted by sodium bisulfite and sulfur dioxide.