The mechanism of action of initiation factor 3 in protein synthesis. II. Association of the 30S ribosomal protein S12 with IF-3

Dimethylsuberimidate was used to crosslink ¹⁴C-labeled chain initiation factor 3 to $\text{E. coli}$ 30S particles. The crosslinked ribosomal proteins were analyzed by dodecyl sulfate polyacrylamide gel electrophoresis, and one major radioactive aggregate was found corresponding to a molecular weight of 41,000. Ribosomal protein S12 was identified to be crosslinked to IF-3 by immunological cross-reactivity.