Interaction of Escherichia coli 30S Ribosomal Subunits with MS2 Phage RNA in the Absence of Initiation Factors

MS2 RNA binds at 0 degrees to 30S subunits from E. coli and, to a smaller extent, to those of a Pseudomonas species, as judged by filtration on nitrocellulose membranes; this mRNA does not bind to 30S subunits from Bacillus brevis or Caulobacter crescentus. Binding does not depend on the presence of initiation factors; it is sensitive to aurintricarboxylic acid but insensitive to edeine and is competitive with such synthetic polynucleotides as poly(U) and poly(AUG). Complex formation can also be detected by electrophoresis on polyacrylamide-agarose gels. By this procedure, E. coli 30S subunits are separated into two major components. Only the more slowly moving component, which contains the ribosomal protein S1, interacts with the RNA.