, Volume 10, Issue 3, pp 261–270 | Cite as

Expression and characterization of recombinant β-subunit hCG homodimer

  • Leslie Lobel
  • Susan Pollak
  • Sujing Wang
  • Michael Chaney
  • Joyce W. Lustbader
Original Articles


We have linked two human chrionic gonadotropin (hCG) β-subunit cDNAs in tandem such that the expressed fusion protein consists of two mature β-subunits joined through the carboxy terminal peptide of the first β-subunit. A single glycine residue is inserted between the two subunits in the fusion protein. Chinese hamster ovary (CHO) cells transformed with a clone that contains the fused cDNAs express and secrete a protein that is consistent with it being a β-hCG homodimer protein. These β-homodimer molecules can recombine with two free α-subunits indicating that both β-subunits within the homodimer are likely folded in their native conformation. Our data also suggest that the two β-subunits fold upon each other as a globular protein and do not appear to exist as a simple fusion of two linear β-subunits. Further-more, the two β-monomer subunits in the fusion protein form a stable homodimer that can bind and activate the hLH/CG receptor specifically. Recombination of the fusion protein with α-subunits appears to favor an arrangement where two α-subunits combine with a single molecule of the fusion protein. The recombined molecule consists of four subunits and is comparable to two tethered hCG moieties, which constitutes a hCG dimer. This hormone dimer can bind and activate the hLH/CG receptor with an activity approximating that of native hCG.

Key Words

Gonadotropin hCG homodimer β-subunit hCG recombinant protein hLH/CG receptor 


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Copyright information

© Humana Press Inc 1999

Authors and Affiliations

  • Leslie Lobel
    • 1
  • Susan Pollak
    • 1
  • Sujing Wang
    • 1
  • Michael Chaney
    • 2
  • Joyce W. Lustbader
    • 1
  1. 1.Department of Obstetrics and Gynecology, Center for Reproductive SciencesColumbia UniversityNew York
  2. 2.Beckman InstituteUniversity of IllinoisUrbana

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