Shine-Dalgarno sequence

Definition

The Shine-Dalgarno sequence is a ribosomal binding site in bacterial mRNA, located upstream of the start codon. It helps align the ribosome with the start codon to initiate protein synthesis.

5 Must Know Facts For Your Next Test

1. The Shine-Dalgarno sequence is typically found 6-10 nucleotides upstream of the AUG start codon.
2. It is complementary to a region on the 16S rRNA of the small ribosomal subunit.
3. Its consensus sequence in E. coli is AGGAGG.
4. Mutations in the Shine-Dalgarno sequence can significantly reduce translation efficiency.
5. This sequence plays a crucial role in translation initiation for prokaryotes but not eukaryotes.

Review Questions

• Where is the Shine-Dalgarno sequence located relative to the start codon?
• What role does the Shine-Dalgarno sequence play in translation initiation?
• How does a mutation in the Shine-Dalgarno sequence affect protein synthesis?

Related terms

16S rRNA: A component of the small subunit of prokaryotic ribosomes that binds to the Shine-Dalgarno sequence.

Start Codon: The first codon of an mRNA transcript translated by a ribosome, typically AUG.

Ribosome Binding Site (RBS): A segment of mRNA where ribosomes bind to initiate translation, including sequences such as the Shine-Dalgarno.