Abstract
The MS2 RNA binding capacity of 30S ribosomal subunits, which is lost when protein S1 is removed, can be restored following incubation with interference factor ialpha and repelleting. Polyacrylamide-agarose gel electrophoresis shows that, under these conditions, a faster moving, non-RNA binding 30S species, which contains no S1, is converted to a slower moving RNA-binding one, having the same mobility as the 30S species that contains protein S1. Factor ialpha binds to single-stranded RNAs in a pattern that closely resembles the RNA binding pattern of initiation factor IF-3.