The cDNA-deduced primary structure of human sex hormone-binding globulin and location of its steroid-binding domain.
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Hammond GL, Underhill DA, Smith CL, Goping IS, Harley MJ, Musto NA, Cheng CY, Bardin CW
The cDNA-deduced primary structure of human sex hormone-binding globulin and location of its steroid-binding domain.
FEBS Lett. 1987 May 4;215(1):100-4.
- PubMed ID
- 3569533 [ View in PubMed]
- Abstract
We have sequenced a cDNA for sex hormone-binding globulin (SHBG) isolated from a phage lambda gt11 human liver cDNA library. The library was screened with a radiolabeled rat androgen-binding protein (ABP) cDNA, and the abundance of SHBG cDNAs was 1 in 750,000 plaques examined. The largest human SHBG cDNA (1194 base-pairs) contained a reading frame for 381 amino acids. This comprised 8 amino acids of a signal peptide followed by 373 residues starting with the known NH2-terminal sequence of human SHBG, and ending with a termination codon. The predicted polypeptide Mr of SHBG is 40,509, and sites of attachment of one O-linked (residue 7) and two N-linked oligosaccharide (residues 351 and 367) chains were identified. Purified SHBG was photoaffinity-labeled with delta 6-[3H]testosterone and cleaved with trypsin. The labeled tryptic fragment was isolated by reverse-phase HPLC, and its NH2-terminal sequence was determined. The results suggest that a portion of the steroid-binding domain of SHBG is located between residue 296 and the 35 predominantly hydrophilic residues at the C-terminus of the protein.