Modification of the dna sequence between the shine-dalgarno sequence and the start codon of the trp operon to increase protein expression

Abstract From the Canadian patent

Abstract of the Disclosure: When, in the trp operon of E. coli, the adenosine immediately upstream of the ATG start codon is replaced by cytidine, and guanosine is connected downstream of the start codon ATG, then an Nco I cleavage site which permits cloning is obtained. The operon thus modified results in very strong expression of the gene downstream of the start codon. In addition, it is possible for the formation of .beta.-lactamase to be increased, which results in increased ampicillin resistance, which can be utilized for selection.