What is Shine Dalgarno Sequence?

 Shine Dalgarno Sequence-

 Definition-It is a consensus conserved sequence that binds with ribosome         
 binding site which  centered about 8 bp upstream of  translation initiation       
 codon(AUG) .Eukaryotes doesn't have Shine Dalgarno Sequence.

  In E.Coli-

• Ribosome consist of r-RNA and proteins. In the smaller subunit 16SrRNA is present. Shine Dalgarno Sequence (AGGAGGU) acts as a signal for binding of ribosome to the initiation codon (AUG).

•  Ribosome then scan through out  the m-RNA for the  anti Dalgarno Sequence(complementary sequence ) that is (ACCUCCUUA),as it is complementary to a region at the 3' end of the 16S rRNA  in the smaller subunit.

•  Base pairing between the Shine-Dalgarno sequence in mRNA and the 3' end of 16S  rRNA is of prime importance for initiation of translation by bacterial ribosomes.

• The Shine-Dalgarno sequence exists both in bacteria and archaea.

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1/deck/5311653

MCQS. 

1.A Shine-Dalgarno sequence

(A) serves as a binding site for bacterial ribosomes

(B) is involved in bacterial transcription

(C) forms part of mRNA trailers

(D) serves as a recognition site for termination of translation

Ans. A

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