Basepairing of oligonucleotides to the 3′ end of 16S ribosomal RNA is not stabilized by ribosomal proteins

Abstract
We have studied the binding of the octanucleotide (5′–3′)d(AAGGAGGT) which is fully complementary to the 3′ end of 16S ribosomal RNA, to ribosomes and to the isolated target sequence (5′–31)(ACCUCCUUA). The binding constant for 30S or 70S ribosomes is (5 ±2)×107mol−1, whereas the duplex containing the octa- and the nonanucleotide has an association constant of (6±3)×107 mol−1. The two values are the same within the experimental error. This result suggests that basepairing at the 3′ end of 16S rRNA is not stabilized by ribosomal proteins.