Question

Explain the roles of the Shine-Dalgarno (SD) sequence in prokaryote translation.

Answer 1

Shine-Dalgarno (SD) sequence : It is ribosomal bonding site which is generally 8-12 specific nucleotide sequence which is upstream of start codon i.e AUG bases in the mRNA which helps in determining the position of start codon and initiates the translation process in prokaroytes .

It interacts with the complementary sequence in the 3' end of 16S rRNA in the small ribosomal subunit which is known as Anti-shine-Dalgarno (aSD) sequence. This interacts specifically with the small ribosomal subunit.

The RNA sequence helps in recruiting the ribosome to the messenger RNA and initiate the protein synthesis by aligning the ribosome with the start codon.

The sequence at the 3' end of the rRNA helps in determining the capacity of the prokaryotic ribosome to translate the particular gene in the mRNA.