Comparison of the reactions of chemically reactive analogs of U-G-A and of A-U-G with ribosomes of Escherichia coli

Abstract

The chemically reactive analog of U-G-A, 5′-{4(Bromo-[2-¹⁴C] acetamido) phenylphospho} - uridylyl-(3′-5′) - guanylyl-(3′-5′) adenosine has a 20 fold lower affinity to 70S ribosomes than the corresponding analog of A-U-G though the U-G-A analog also preferentially reacts with protein S18 of 70S ribosomes. This reaction programs ribosomes for EF-T dependent binding. Therefore, it is concluded that this protein is part of the A'-site of the ribosomal codon binding site