Question

What sequence is normally placed between the end of a promoter in the start codon (ATG) to ensure efficient translation? include the name of the sequence and an example of it

Answer 1

The promoter sequence is the recognition site for the attachment of RNA polymerase, the enzyme responsible for transcription. The initiator or start codonon m-RNA is the sequence AUG, and corresponds to the amino acid methionine.

ATG or AUG

The codon for Methionine; the translation initiation codon. Usually, protein translation can only start at a Methionine codon (although this codon may be found elsewhere within the protein sequence as well). In eukaryotic DNA, the sequence is ATG; in RNA it is AUG. Usually, the first AUG in the mRNA is the point at which translation starts, and an open reading frame follows - i.e. the nucleotides taken three at a time will code for the Amino acids of the protein, and a stop codon will be found only when the protein coding region is complete.

   ATG    TAC CAT CGG TTA GAC CCC

MET   TYR HIS ARG LEU ASP PRO

ATG ACC ATC GLY TAG ACC CC

MET THR ILE GLY STOP  THR   

START CODON ; ATG

STOP CODON ; TAG

The start codon marks the site at which translation into protein sequence begins,and the stop codon marks the site at which translation end.