title: Synthetic human follicle-stimulating hormone-beta-(1-15) peptide-amide binds Ca2+ and possesses sequence similarity to calcium binding sites of calmodulin.
abstract: To determine the basis for the previously demonstrated calcium requirement for specific binding of FSH to receptor, 11 overlapping peptide amides representing the entire primary structure of human FSH (hFSH)-beta-subunit were tested for their ability to bind 45Ca2+ as an approach to identifying possible calcium binding regions of the hormone. hFSH-beta-(1-15)-peptide amide bound significant amounts of 45Ca2+. This peptide contains an amino acid sequence similar to that found in the loop structures of the calcium-binding domains of calmodulin. The affinity of hFSH-beta-(1-15)-peptide amide for calcium (Kd = 1.2 +/- 0.3 mM) was similar to that previously reported for a synthetic peptide corresponding to calmodulin binding site III. No such sequence is predicted in the recently deduced primary structure of the FSH receptor. FSH-beta-(1-15) may, therefore, be associated with the calcium requirement for specific binding of FSH to receptor. The calcium binding property of this calmodulin-like peptide also correlates well with its ability to induce uptake of calcium into liposomes via transmembrane channel formation, as previously reported by this laboratory.
authors.affiliation: Department of Biochemistry and Molecular Biology, Albany Medical College, New York 12208.
authors.forename: T A
authors.initials: TA
authors.lastname: Santa-Coloma
authors.forename: P
authors.initials: P
authors.lastname: Grasso
authors.forename: L E
authors.initials: LE
authors.lastname: Reichert
mesh_terms: D000595:Amino Acid Sequence; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000737:chemistry / Q000378:metabolism*; D002853:Chromatography, Liquid / Q000379:methods; D005260:Female; D005640:Follicle Stimulating Hormone / Q000737:chemistry / Q000378:metabolism*; D037201:Follicle Stimulating Hormone, beta Subunit; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D011962:Receptors, FSH / Q000378:metabolism
chemical_list: D002147:Calmodulin; D037201:Follicle Stimulating Hormone, beta Subunit; D010446:Peptide Fragments; D011962:Receptors, FSH; C068939:follicle stimulating hormone, beta subunit (1-15); D005640:Follicle Stimulating Hormone; D002118:Calcium