Crosslinked bifunctional gonadotropin analogs with reduced efficacy.
The N-linked oligosaccharides on human choriogonadotropin (hCG) and follitropin (hFSH) alpha-subunit loop 2 (alpha2) have a dominant influence on hormone efficacy. hCG analogs lacking this oligosaccharide retain approximately 40% the efficacy of the fully glycosylated hormone in cyclic AMP accumulation assays. Previous efforts to reduce efficacy further have involved removing the other N-linked oligosaccharides. We found that some intersubunit disulfide crosslinks reduced the efficacies of hCG analogs lacking only the alpha2 oligosaccharide. The least active analog was an hCG/hFSH chimera containing hFSH residues 95-108 in place of hCG residues 101-114 and a disulfide bond between alpha-subunit residue 37 and beta-subunit residue 33. While it bound lutropin receptors 2- to 3-fold better than hCG and follitropin receptors 10-30% as well as hFSH, it had less than 10% and 5% the efficacies of either hormone. This suggests that complete deglycosylation will not be required to produce glycoprotein hormone analogs that have low efficacies.
Bernard
Michael P
MP
Department of OBGYN, Robert Wood Johnson (Rutgers) Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA.
Lin
Win
W
Myers
Rebecca
R
Cao
Donghui
D
Xing
Yongna
Y
Moyle
William R
WR
D000595:Amino Acid Sequence; D000818:Animals; D001681:Biological Assay; D019556:COS Cells; D002522:Chlorocebus aethiops; D006063:Chorionic Gonadotropin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism*; D004220:Disulfides / Q000737:chemistry; D006031:Glycosylation; D006801:Humans; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009844:Oligosaccharides / Q000737:chemistry / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects*
D006063:Chorionic Gonadotropin; D004220:Disulfides; D009844:Oligosaccharides; D000242:Cyclic AMP