Kozak sequence

From Wikipedia, the free encyclopedia

Protein translation is generally initiated from an AUG methionine codon, although alternate start codons are common in prokaryotes. Eukaryotes contain a short recognition sequence including this codon that enhances the initial binding of the small subunit of the ribosome to the mRNA template. For vertebrates, this sequence was described and named the Kozak sequence. The consensus sequence is:

(GCC)RCCAUGG

Here R represents a purine (A or G), and the (GCC) is less conserved. A briefer version is:

ACCAUGG

Start codons adhering to this sequence may have enhanced expression. Kozak found the purine at position –3 before the AUG, usually A, to be the most conserved; it was found in 97% of 699 vertebrate mRNAs studies. In the absence of this purine, the G following the AUG and a closer general adherence to the Kozak consensus sequence are usually found.

References:

Kozak, M. An analysis of 5'-noncoding sequences from 699 vertebrate messenger RNAs. Nucleic Acids Res. 1987, 15(20):8125-48

Kozak, M. Point mutations define a sequence flanking the AUG initiator codon that modulates translation by eukaryotic ribosomes. Cell. 1986, 44(2):283-92.

See also:

kozak consensus sequence - The same sequence.