Glycoprotein Hormones: Some Aspects of Studies of Secondary and Tertiary Structure

Abstract

The glycoprotein hormones, thyrotropin (TSH), lutropin (LH), follitropin (FSH), and human choriogonadotropin (hCG), are a particularly interesting group with which to study structure—function relationships because they share a common subunit (α) and exhibit homologous linear sequences in their hormone-specific (s) subunits (see Figs. 1 and 2). After the initial determination of the primary structures of bovine TSH (bTSH) and ovine LH (oLH), considerable effort in many laboratories has been directed toward assessment of their secondary and tertiary structures with the goal of elucidating the structural requirements of hormone—receptor interactions. Interesting and valuable information concerning the domains of another hormone, insulin, has been obtained (e.g., Pullen et al., 1976) based on crystallographic data (Blundell et al., 1972) and chemical modification studies, and it is hoped that similar data will be forthcoming with the glycoprotein hormones even without information on the exact structure and topography at cell-surface receptors for polypeptide hormones.