Identification of a 48 S preinitiation complex in reticulocyte lysate.
Abstract
When the polypeptide initiation sequence is interrupted by the peptide antibiotic edeine, the sedimentation coefficient of the native small ribosomal subunit is increased from 43 S to 48 S. Formation of the 48 SN particle is absolutely dependent on the binding of both Met-tRNAf and globin mRNA. These results support the concept that Met-tRNAf binds to the native small ribosomal subunit before mRNA, and that processes involved in mRNA binding to the 43 SN preinitiation complex may be the rate-limiting step of 80 S initiation complex formation.
