Protein Factors involved in Polypeptide Chain Initiation in Escherichia coli
This extract was created in the absence of an abstract.
Excerpt
The initiation of polypeptide chains synthesized from natural messenger RNA (mRNA) has been shown to proceed in cell-free bacterial systems with the incorporation of N-formyl-methionine (F-met) at the N-terminal positions (Adams and Capecchi, 1966; Webster et al., 1966). Two species of Met-tRNA have been found: Met-tRNAM, which recognizes an internal AUG codon and inserts methionine into a growing polypeptide chain, and Met-tRNAF, which is first formylated and then recognizes an AUG or GUG codon at the start of a cistron and initiates a new polypeptide chain (Clark and Marcker, 1966). A number of workers have reported that cell-free bacterial systems consisting of salt-washed ribosomes, GTP, and soluble factors are incapable of translating natural mRNA, while retaining full activity in Poly U-dependent polyphenylalanine synthesis (Eisenstadt and Brawerman, 1966; Revel and Gros, 1966; Stanley et al., 1966). Addition of ribosomal salt-wash restores activity toward natural mRNA, and has been shown to be...
