title: Complete amino acid sequences of five dimeric and four monomeric forms of metallothionein from the edible mussel Mytilus edulis.
abstract: Cadmium-induced metallothioneins from the common sea mussel, Mytilus edulis, were shown to comprise of two groups of isoforms having apparent molecular masses of 10 kDa and 20 kDa. The 10-kDa group was resolved by anion-exchange chromatography into four fractions while the 20-kDa group was resolved into three fractions using this method. After metal removal and S-methylation of the cysteine residues using methyl-p-nitrobenzenesulphonate the complete amino acid sequences were determined. Five isoforms of the 20-kDa group were shown to possess monomeric units consisting of 71 amino acids. These proteins were distinct from the four 72-amino-acid proteins of the 10-kDa group. The FASTA algorithm has been used to compare the degree of similarity between the mussel metallothionein MT-10-IV isoform and other metallothioneins. The mussel MT-10-IV isoform exhibited substantial similarity to other molluscan metallothioneins. Moreover, the mussel metallothionein exhibited more similarity to vertebrate metallothioneins than to those of non-molluscan invertebrates, thus suggesting that the mussel metallothioneins are class I metallothioneins.
authors.affiliation: Department of Molecular and Cell Biology, University of Aberdeen, Scotland.
authors.forename: E A
authors.initials: EA
authors.lastname: Mackay
authors.forename: J
authors.initials: J
authors.lastname: Overnell
authors.forename: B
authors.initials: B
authors.lastname: Dunbar
authors.forename: I
authors.initials: I
authors.lastname: Davidson
authors.forename: P E
authors.initials: PE
authors.lastname: Hunziker
authors.forename: J H
authors.initials: JH
authors.lastname: Kägi
authors.forename: J E
authors.initials: JE
authors.lastname: Fothergill
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D049872:Bivalvia / Q000737:chemistry*; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D006801:Humans; D008668:Metallothionein / Q000737:chemistry* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D017386:Sequence Homology, Amino Acid
chemical_list: D008668:Metallothionein