CLONING OF CDNA FOR THE PROTEIN DISULFIDE-ISOMERASE FROM ASPERGILLUS-NIGER STRAIN NNRL3 USING PCR

The protein disulfide isomerase from A. niger was cloned as a series o f overlapping DNA-fragments generated using polymerase chain reaction technology and primers derived from conserved regions of published PDI amino acid sequences. The 5' end of the gene was amplified using inve rse PCR. Comparison of amino acid sequences from rat, wheat, yeast and another fungal species shows that the thioredoxin like active sites a re strongly conserved. The C-terminus of the fungal PDI contains an en doplasmatic reticulum (ER) retention signal (HDEL) that is preferred b y yeast.