title: Methionine acts as a "magnet" in photoaffinity crosslinking experiments.
abstract: Photoaffinity crosslinking has been utilized to probe the nature of the ligand-receptor interface for a number of G protein-coupled receptor systems. Often the photoreactive benzophenone moiety incorporated in the ligand is found to react with a methionine in the receptor. We introduced methionines one-at-a-time into the region 163-176 of the parathyroid hormone receptor, and find that crosslinking occurs to the side-chain of methionine over a range of 11 amino acids. We call this the "Magnet Effect" of methionine. Hence, crosslinking contact points can be significantly shifted by the presence of methionine in a receptor domain.
authors.affiliation: Department of Physiology, Tufts University School of Medicine, 136 Harrison Ave, M&V 7, Boston, MA 02111, USA. Angela.Wittelsberger@tufts.edu
authors.forename: Angela
authors.initials: A
authors.lastname: Wittelsberger
authors.forename: Beena E
authors.initials: BE
authors.lastname: Thomas
authors.forename: Dale F
authors.initials: DF
authors.lastname: Mierke
authors.forename: Michael
authors.initials: M
authors.lastname: Rosenblatt
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001577:Benzophenones / Q000737:chemistry; D019556:COS Cells; D002522:Chlorocebus aethiops; D003432:Cross-Linking Reagents / Q000737:chemistry*; D006801:Humans; D008715:Methionine / Q000737:chemistry* / Q000235:genetics; D010777:Photochemistry; D044168:Receptor, Parathyroid Hormone, Type 1 / Q000737:chemistry
chemical_list: D001577:Benzophenones; D003432:Cross-Linking Reagents; D044168:Receptor, Parathyroid Hormone, Type 1; C047723:benzophenone; D008715:Methionine