Characterization of the human gene for a polypeptide that acts both as the β subunit of prolyl 4-hydroxylase and as protein disulfide isomerase

Academic Article


  • A single polypeptide acts as the β subunit of prolyl 4-hydroxylase and the enzyme protein disulfide isomerase and may also function as a cellular thyroid hormone binding protein. We report here that the human gene for this polypeptide is about 18 kilobase pairs and consists of 11 exons. The two thioredoxin-like regions are coded by exons 1-2 and 8-9, respectively. The codons for the two presumed active sites of protein disulfide isomerase, each a Cys-Gly-His-Cys sequence, are located 12 base pairs from the beginning of exons 2 and 9. The last 3 amino acids coded by exons 1 and 8 and the first 9 amino acids coded by exons 2 and 9, including a broken codon for Tyr, are identical in the respective exon-intron junctions. These regions are also highly homologous to the active sites of bacterial thioredoxins. The data suggest that evolution of this gene has involved exons shuffling and duplication of a two-exon unit, in which the internal exon-intron junctions have been entirely conserved. The region between exons 1-2 and 8-9 appears to contain other duplications. The 5' flanking sequences contain a TATA box, six CCAAT boxes, and other elements which may be involved in regulation of the cellular amounts of this polypeptide.
  • Published In

    Pubmed Id

  • 22241528
  • Author List

  • Tasanen K; Parkkonen T; Chow LT; Kivirikko KI; Pihlajaniemi T
  • Start Page

  • 16218
  • End Page

  • 16224
  • Volume

  • 263
  • Issue

  • 31