Question

The Shine-Dalgarno sequence facilitates the binding of mRNAs to the

• A. 50S ribosomal subunit via the 23S rRNA
• B. 30S ribosomal subunit via the 16S rRNA
• C. 55S ribosomal subunit via the 5S rRNA
• D. 30S ribosomal subunit via the 5S rRNA

Answer 1

The correct option is B 30S ribosomal subunit via the 16S rRNA

Initiation of protein synthesis in eubacteria involves association of 30S and 50S subunits.

A ribosomal binding site in the bacterial and archaeal mRNA, is a specific structure that enables the process of initiation of protein synthesis. A sequence (typically seven nucleotides) upstream of the first AUG codon in the case of prokaryotes is called the Shine-Dalgarno sequence. The Shine-Dalgarno sequence is complementary to a region at the 3' end of the 16S rRNA, the one present in the small subunit, and it is thought that base pairing between the two is involved in the attachment of the small subunit to the mRNA.