Diversity of metallothioneins in the American oyster, Crassostrea virginica, revealed by transcriptomic and proteomic approaches

摘要: Metallothioneins are typically low relative molecular mass (6000–7000), sulfhydryl‐rich metal‐binding proteins with characteristic repeating cysteine motifs (Cys‐X‐Cys or Cys‐Xn‐Cys) and a prolate ellipsoid shape containing single α‐ and β‐domains. While functionally diverse, they play important roles in the homeostasis, detoxification and stress response of metals. The originally reported metallothionein of the American oyster, Crassostrea virginica showed the canonical molluscan αβ‐domain structure. Oyster metallothioneins have been characterized as cDNA and as expressed proteins, and here it is shown that the previously reported metallothionein is a prototypical member of a subfamily (designated as CvMT‐I) of αβ‐domain metallothioneins. A second extensive subfamily of oyster metallothioneins (designated as CvMT‐II) has apparently arisen from (a) a stop mutation that truncates the protein after the α …