DETERMINATION OF THE SEQUENCE OF THE YEAST YCL313 GENE LOCALIZED ON CHROMOSOME .3. HOMOLOGY WITH THE PROTEIN DISULFIDE ISOMERASE (PDI GENE-PRODUCT) OF OTHER ORGANISMS

We have determined the nucleotide sequence of the YCL313 gene as part of the YIp5 A1G clone localized on the left arm of chromosome III. This YCL313 gene encodes a protein of 522 amino acids (MW 58.3 kDa) which has large homologies with the human, mouse, chicken, bovine and rat PDI gene products. In these organisms the PDI gene encodes the protein disulfide isomerase (EC 5.3.4.1) also called S-S rearrangase, an enzyme that catalyses the rearrangements of S-S bonds in proteins. This enzyme is probably involved in protein folding within the lumen of the endoplasmic reticulum. These sequence homologies suggest that YCL313 is the yeast equivalent of the PDI gene. Gene disruption of YCL313 leads to a lethal phenotype indicating that this gene is essential for cell survival.