Kozak consensus sequence in expression vector - is substitutable? (Aug/27/2003 )
As I understand the Kozak sequence is few bp upstream of ATG and a single G after ATG (gccgccaccATGg). But how come the downstream G after ATG can be added/altered without changing the CDS of the protein? Can I just add gccgccacc infront of ATG without downstream G for my expression vector?
I suppose Yes.
The Kozak consensus sequence was originally defined as ACCAUGG following an analysis of the effects of single mutations surrounding the initiation codon (AUG) on translation of the preproinsulin gene by Kozak. Subsequent mutagenesis studies and a survey of 699 vertebrate mRNAs extended the consensus sequence for translation initiation to GCCGCCACCAUGG.
So it is just a CONSENSUS sequence that greatly facilitate the initial binding of mRNA to the small subunit of the ribosome. Sequence similar to that will also do, propably with less efficiency.
Yeah, no need to change the nucleotide following the ATG. And the stripped down Kozac is just CCACCatg and works well.