Identification of amino acid residues 300-315 of the rat FSH receptor as a hormone binding domain: evidence for its interaction with specific regions of FSH beta-subunit.
We previously reported that residues 9-30 of the extracellular N-terminus domain of the rat FSH receptor, which has no homologous sequence in receptors for related pituitary glycoprotein hormones, represented a specific FSH binding domain. Further examination of its deduced primary structure identified another region, residues 300-315, which was also unique to the FSH receptor. To determine whether this region of the FSH receptor was involved in hormone binding, a synthetic peptide corresponding to residues 300-315 was studied with respect to its ability to bind FSH, as well as a series of nine overlapping synthetic peptides corresponding to the entire primary structure of the hormone specific FSH beta-subunit. 125I-FSH rec-(300-315) peptide bound to immobilized human, ovine and bovine FSH, but not to prolactin or ovalbumin. Of the nine synthetic peptides studied, binding was restricted to FSH beta residues 21-35, and to a much lesser extent (20%) to residues 11-25. All binding was abolished in the presence of excess solubilized FSH receptor. Earlier studies indicated that although FSH binds to FSH rec(9-30) peptide, residues 11-25 or 21-35 of the FSH beta-subunit were not involved. Our results suggest the FSH receptor N-terminus, extracellular residues 300-315, may define a FSH binding site, and that binding of FSH beta-subunit may occur via interactions with FSH beta 21-35 and 11-25.
Leng
N
N
Department of Biochemistry and Molecular Biology, Albany Medical College, NY 12208, USA.
Dattatreyamurty
B
B
Reichert
L E
LE
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D005640:Follicle Stimulating Hormone / Q000378:metabolism*; D008969:Molecular Sequence Data; D051381:Rats; D011962:Receptors, FSH / Q000737:chemistry / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
D000596:Amino Acids; D011962:Receptors, FSH; D005640:Follicle Stimulating Hormone