Open AccessPrimary Structure of EPV20, a Secretory Glycoprotein Containing a Previously Uncharacterized Type of Domain
Author(s) -
Larsen Lotte B.,
Ravn Peter,
Boisen Anni,
Berglund Lars,
Petersen Torben E.
Publication year - 1997
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1997.0437a.x
Subject(s) - signal peptide , complementary dna , glycoprotein , protein primary structure , peptide sequence , biochemistry , microbiology and biotechnology , biology , chemistry , gene
A 20‐kDa glycoprotein, EPV20, was isolated from bovine milk and characterized. The primary structure was determined by cDNA and protein sequencing combined with mass spectrometry. EPV20 is a 130‐residue polypeptide synthesized with a 19‐residue signal peptide. The function of EPV20 is unknown, but it displays 79% sequence similarity to a putative protein deduced from a human testis cDNA sequence designated HE1 (human epididymis clone 1) (Kirchhoff, C., 1992. EMBL/GeneBank/DDBJ Databases, accession number X6769X). Northern blot analysis showed the bovine EPV20 to be expressed in kidney, spleen, liver and mammary gland, but remarkably not in bovine testis. The six Cys residues of EPV20 were found to be disulfide‐linked in a 1–6, 2–3 and 4–5 pattern. This disulfide arrangement has been observed in other proteins, e.g. in human prostatic acid phosphatase, but the spacing between the cystines differs. Therefore, EPV20 represents a new structure among the large group of proteins containing domains with three disulfide bonds.