Differences in 23 S rRNA-protein neighbourhood in Escherichia coli 70 S ribosomes and 70 S initiation complex. Probing by bifunctional Pt(II)-containing reagent.

ABSTRACT

rRNA-protein cross-links in free E. coli 35S-labeled 70 S ribosomes and in the initiation complex 35S-labeled 70 S ribosome.AUGU6.fMet-tRNA(fMet) were studied with the aid of a new type of binuclear Pt(II) compound - dichlorotetra-ammine(1,6-hexamethylenediaminediplatinum++ +) dichloride. The use of this reagent allowed us to reveal differences in the rRNA-protein neighbourhood in free 70 S ribosomes and in the initiation complex. Proteins L3, L6, L23 and L25 were shown to cross-link to 23 S rRNA only in the initiation complex, whereas proteins L1, L13, L14, L16, L17, L18, L22, L28 and S1 did so in both free ribosomes and the complex. 16 S rRNA was found to be cross-linked preferentially to a single protein, S1, in both states of the ribosomes.