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Updated: Oct 28, 2026

High-throughput Purification of Affinity-tagged Recombinant Proteins
Published on: August 26, 2012
Initiation factors of protein biosynthesis in bacteria and their structural relationship to elongation and
S Brock1, K Szkaradkiewicz, M Sprinzl
1Laboratorium für Biochemie, Universität Bayreuth, Germany.
Abstract:
Initiation of protein biosynthesis in bacteria requires three initiation factors: initiation factor 1, initiation factor 2 and initiation factor 3. The mechanism by which initiation factors form the 70S initiation complex with initiator fMet-tRNA(fMet) interacting with the initiation codon in the ribosomal P site and the second mRNA codon exposed in the A site is not yet understood. Here, we present a model for the function of initiation factors 1 and 2 that is based on the analysis of sequence homologies, biochemical evidence and the present knowledge of the three-dimensional structures of translation factors and ribosomes. The model predicts that initiation factors 1 and 2 interact with the ribosomal A site mimicking the structure of the elongation factor G. We present data that extend the mimicry hypothesis to initiation factors 1 and 2, originally postulated for the aminoacyl-tRNA x elongation factor Tu x GTP ternary complex, elongation factor G and release factors.
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