title: Molecular characterization and function analysis of MT-10 and MT-20 metallothionein isoforms from Mytilus galloprovincialis.
abstract: Structure and function of molluscan metallothioneins (MTs) are still poorly understood. The sea mussel Mytilus galloprovincialis displays two MT isoforms which differ in both primary sequences and physiological functions. MT-10 is the constitutive isoform, whereas MT-20 is mainly induced by cadmium (Cd). Both MTs were produced as recombinant proteins and showed identical Cd content and similar Cd-binding properties. Conversely, circular dichroism disclosed marked differences in the secondary conformations of the two Cd(7)-MTs. The possible relapses of these structural differences on protein stability and function were assessed. MT-10 presented a higher thermal stability and a more compact structure than MT-20, as it was inferred by absorption and emission spectroscopy studies. Moreover, the kinetics of Cd-release clearly indicated that MT-10 is much more sensitive to oxidation than is MT-20. The observed differences between MT-10 and MT-20 are discussed in terms of the different physiological roles exerted by the two isoforms in mussel.
authors.affiliation: Department of Biology, University of Genova, Genova, Corso Europa 26, 16132 Genova, Italy. Laura.Vergani@unige.it
authors.forename: Laura
authors.initials: L
authors.lastname: Vergani
authors.forename: Myriam
authors.initials: M
authors.lastname: Grattarola
authors.forename: Elena
authors.initials: E
authors.lastname: Grasselli
authors.forename: Francesco
authors.initials: F
authors.lastname: Dondero
authors.forename: Aldo
authors.initials: A
authors.lastname: Viarengo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003198:Computer Simulation; D008668:Metallothionein / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D049878:Mytilus / Q000737:chemistry*; D011487:Protein Conformation; D020033:Protein Isoforms / Q000737:chemistry*
chemical_list: D020033:Protein Isoforms; D008668:Metallothionein