Figure1: Cystine knot organization and glycosylation of human FSH α- and β-subunits. The cystine (Cys) knot disulfide bonds are indicated as lines. The loops are designated αL1, αL2, αL3, βL1, βL2, and βL3, as indicated. The FSHα seatbelt loop that embraces αL2 of FSHα in the heterodimer is indicated. The locations of the asparagine (Asn) N-glycosylation sites on loops αL2, αL2, and βL1 show diagrammatic representations of a glycan found at each site by glycopeptide mass spectrometry.