Kozak consensus sequence
The Kozak sequence is not to be confused with the ribosomal binding site ( RBS ) , that being either the 5′ cap of a messenger RNA or an internal ribosome entry site ( IRES ) . 
<triplet> ribosomal binding site <subj> messenger RNA <obj> part of <triplet> 5′ cap <subj> messenger RNA <obj> part of