The Shine-Dalgarno sequence: The ribosome’s time to Shine

OTHER VIDEOS YOU MIGHT LIKE:
• Science NONfiction: The story of synthetic bacterial genomes -    • Science NONfiction: The story of synthetic...  
• Unravelling the mysteries of molecular biology: The timeline of polyadenylate polymerase discovery -    • The discovery of polyadenylate polymerase:...  
• Discovery of primase: a puzzle piece in understanding DNA synthesis -    • Discovery of primase: a puzzle piece in un...  

It is the 1970’s in Australia. The roller skates are out, the bell bottoms are flaring and Led Zepplin is blaring on the radio. But what you don’t know, is that in a science lab in Canberra, something amazing was about to be discovered. The beginnings of biotechnology were about to unfold. Scientists Lynn Dalgarno and Phd student John Shine found a nine-nucleotide ribosomal RNA (rRNA) sequence that had remarkable conservation between species. This small but powerful sequence coordinates the appropriate binding of the ribosome to messenger RNA as well as scan for stop codons to signal the release of the new protein. It does this through complementary base paring with known terminator codons and 5’-UTR sequences. Without this sequence, proteins would not be made – and we definitely need those. The significance of this sequence is so great, that if it is cleaved off, translation ceases. Incredible. The sequence became so useful that it was given the name, the Shine-Dalgarno (SD) sequence. Fast forward to today and researchers regularly use this same sequence to produce new antibiotics, improve the synthesis of insulin and much, much more. We use bacteria so often in research, that understanding how they make proteins is essential for developing new ways to harness their biology for our own good.

Creator: Rachael Taylor

References:
Colicin E3 cleavage of 16S rRNA impairs decoding and accelerates tRNA translocation on Escherichia coli ribosomes. Lancaster, L. E., Savelsbergh, A., Kleanthous, C., Wintermeyer, W., & Rodnina, M. V. Molecular microbiology. 2008; 69(2): 390–401. doi: 10.1111/j.1365-2958.2008.06283.x
Conserved terminal sequence in 18S rRNA may represent terminator anticodons.
Shine J, Dalgarno L. Nature: New Biology. 1973 Oct; 245: 261-2. doi: 10.1038/newbio245261a0
How ribosomes select initiator regions in mRNA: Base pair formation between the 3′ terminus of 16S rRNA and the mRNA during initiation of protein synthesis in Escherichia coli. Steitz, J. A, Jakes, K. Proc Natl Acad Sci U S A. 1975; 72(12), 4734–8. doi: 10.1073/pnas.72.12.4734
The 3'-terminal sequence of Escherichia coli 16S ribosomal RNA: complementarity to nonsense triplets and ribosome binding sites. Shine J, Dalgarno L. Proc Natl Acad Sci U S A. 1974 Apr; 71(4):1342-6. doi: 10.1073/pnas.71.4.1342.