Patent ID: 7037684

Claim:
A DNA which enables co-expression of a protein disulfide isomerase and a polypeptide having disulfide bonds, comprising at least one promoter required for gene expression, two identical or different Shine-Dalgamo sequences (SD), two identical or different sequences encoding signal peptides of cell wall proteins (CWP) of a bacterium of the genus Bacillus (CWPsp), a gene encoding a polypeptide having disulfide bonds which is a fusion protein comprising human insulin, and a gene encoding protein disulfide isomerase (PDI) that are ligated to each other as represented by the following formula: 5′-Promoter-SD-CWPsp-X 1 -(Promoter)n-SD-CWPsp-X 2 -3′, wherein X 1 =fusion protein and X 2 =PDI, or X 1 =PDI and X 2 =fusion protein, and n=0 or 1, wherein if n=1 then the first promoter and the second promoter are identical or different and wherein if n=0, there is only one promoter, wherein the fusion protein comprising a human insulin is represented by the following formula: MWPmp9-GSLQPR-B chain-RGHRP-Linker-PR-A chain, wherein MWPmp9 represents 9 amino acids from the N terminus of a middle-wall mature protein of bacteria of the genus Bacillus ; GSLQPR, RGHRP and PR each represents amino acids 30–35, amino acids 66–70 and amino acids 34–35 of SEQ ID NO:24, A chain and B chain respectively represent the A chain and B chain of human insulin; and Linker represents a linker consisting of any amino acids.