1 Proteins
| DB identifier | UniProt Accession | Secondary Identifier | Organism Name | Length |
|---|---|---|---|---|
| Crahi.0003s0250.1.p | PAC:39981020 | Crambe hispanica |
46
 |
| Type: | Family | Name: | Metallothionein, mollusc |
| Description: | Metallothioneins (MT) are small proteins that bind heavy metals, such as zinc, copper, cadmium, nickel, etc. They have a high content of cysteine residues that bind the metal ions through clusters of thiolate bonds [, ]. An empirical classification into three classes has been proposed by Fowler and coworkers [] and Kojima []. Members of class I are defined to include polypeptides related in the positions of their cysteines to equine MT-1B, and include mammalian MTs as well as from crustaceans and molluscs. Class II groups MTs from a variety of species, including sea urchins,fungi, insects and cyanobacteria. Class III MTs are atypical polypeptides composed of gamma-glutamylcysteinyl units [].This original classification system has been found to be limited, in the sense that it does not allow clear differentiation of patterns of structural similarities, either between or within classes. Consequently, all class I and class II MTs (the proteinaceous sequences) have now been grouped into families of phylogenetically-related and thus alignable sequences. This system subdivides the MT superfamily into families, subfamilies, subgroups, and isolated isoforms and alleles. The metallothionein superfamily comprises all polypeptides that resemble equine renal metallothionein in several respects []: e.g., low molecular weight; high metal content; amino acid composition with high Cys and low aromatic residue content; unique sequence with characteristic distribution of cysteines, and spectroscopic manifestations indicative of metal thiolate clusters. A MT family subsumes MTs that share particular sequence-specific features and are thought to be evolutionarily related. The inclusion of a MT within a family presupposes that its amino acid sequence is alignable with that of all members. Fifteen MT families have been characterised, each family being identified by its number and its taxonomic range. Mollusc MTs are 64-75 residue proteins. They usually contain 18-23 Cys, at least 13 of them are totally conserved. The protein sequence is divided into two structural domains. The Cys residues are arranged in C-X-C groups, and a C-X-X-C grouping is also observed. In particular, the consensus pattern C-x-C-x(3)-C-T-G-x(3)-C-x-C-x(3)-C-x-C-K has been shown to be diagnostic of family 2 metallothioneins. MTs locate at the C terminus of the sequence. These proteins show more similarily to the vertebrate metallothioneins than to those from other invertebrate phyla [], and on this basis they are classified as class I metallothioneins. The protein is induced by cadmium and binds divalent cations of several transition elements, including cadmium, zinc and copper. Family 2 includes subfamilies: mo1, mo2, mog, mo, which hit the same entry, except the subfamily mog. | Short Name: | Metalthion_mollusc |
| DB identifier | UniProt Accession | Secondary Identifier | Organism Name | Length |
|---|---|---|---|---|
| Crahi.0003s0250.1.p | PAC:39981020 | Crambe hispanica |
46
|
