title: The small myelin-associated glycoprotein is a zinc-binding protein.
abstract: The myelin-associated glycoprotein is a transmembrane cell adhesion molecule expressed specifically by myelinating glial cells of the nervous system. Its two isoforms, whose amino acid sequences differ only by their respective cytoplasmic carboxy-terminal domains, are important for the formation and maintenance of a normal functional myelin sheath. In this study, by using recombinant proteins, we identify the cytoplasmic domain of the small isoform of the myelin-associated glycoprotein as a zinc-binding protein. The observed dissociation constant lies in the low micromolar range (K(D) = 6-7 microM). The binding of zinc by the small myelin-associated glycoprotein induces a conformational change that enables the protein to reversibly bind to a hydrophobic phenyl-Sepharose matrix. Our results also suggest that zinc may induce dimerization of the small myelin-associated glycoprotein. We suggest roles for zinc in the stabilization of the structure of the cytoplasmic domain of the small myelin-associated glycoprotein and in protein-protein interactions that involve this short domain.
authors.affiliation: Department of Pathology, University of Oulu, Finland.
authors.forename: P
authors.initials: P
authors.lastname: Kursula
authors.forename: G
authors.initials: G
authors.lastname: Meriläinen
authors.forename: V P
authors.initials: VP
authors.lastname: Lehto
authors.forename: A M
authors.initials: AM
authors.lastname: Heape
mesh_terms: D002846:Chromatography, Affinity; D003593:Cytoplasm / Q000737:chemistry; D019281:Dimerization; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism; D005982:Glutathione Transferase / Q000235:genetics; D018992:Myelin-Associated Glycoprotein / Q000737:chemistry / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015032:Zinc / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D018992:Myelin-Associated Glycoprotein; D011993:Recombinant Fusion Proteins; D005982:Glutathione Transferase; D015032:Zinc