Determination of alpha-subunit contact regions of human follicle-stimulating hormone beta-subunit using synthetic peptides.
Follicle-stimulating hormone (FSH) is a glycoprotein hormone composed of two different subunits designated FSH-alpha and FSH-beta. Using synthetic peptides corresponding to the primary structure of human (h) FSH-beta subunit, we previously identified two regions of the beta-subunit, hFSH-(33-53) and hFSH-(81-95), as receptor binding regions. In this report, we tested the ability of synthetic peptides to interact with hFSH-alpha-subunit. Synthetic peptides corresponding to hFSH-beta-(11-25), (41-55), (51-65), and (101-111) were able to bind specifically radioiodinated hFSH-alpha-subunit, suggesting that they represent regions of interaction with the alpha-subunit. These experimental results were in agreement with the location of alpha-subunit contact regions predicted by sequence analysis. Peptides of hFSH-beta-subunit showing maximum specific binding to the alpha-subunit were those possessing minimum interaction with receptor whereas those not binding to alpha-subunit corresponded to regions shown to interact with receptor (hFSH-beta-(33-53) and hFSH-beta-(81-95]. The hFSH-beta-subunit, therefore, seems to have two discontinuous receptor binding regions flanked by three alpha-subunit contact regions.
Santa-Coloma
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Department of Biochemistry, Albany Medical College, New York 12208.
Reichert
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D000595:Amino Acid Sequence; D005640:Follicle Stimulating Hormone / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism; D011962:Receptors, FSH / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D013379:Substrate Specificity
D010455:Peptides; D011962:Receptors, FSH; D005640:Follicle Stimulating Hormone