Structure and Metal-Binding of Metallothioneins
Metallothioneins are small proteins that bind and trap heavy metal ions, which protects cells from toxic metals and helps with regulating essential ones. Most of these proteins form two domains, each being able to coordinate three or four divalent metal ions by nine or eleven cysteine residues.
Metallothioneins in snails show a large diversity in primary structures. Some of these metallothioneins became metal selective, which allowed snails to adapt to different environments. The benefits of other modifications such as domain multiplications are not yet understood. We use solution NMR to shed light on the evolution of these proteins, focusing on metal uptake, transfer and selectivity of snail metallothioneins.
C. Baumann, A. Beil. S. Jurt, M Niederwanger, O. Palacios, M. Capdevila, S. Atrian, R. Dallinger, O. Zerbe: Structural adaptation of a protein to increased metal stress: NMR structure of a marine snail metallothionein with an additional domain (2017) Angew. Chem.Int. Ed., 56, 4617-4622.
A. Beil, S. Jurt, R. Walser, T. Schönhut, P. Güntert, Òscar Palacios, S. Atrian, Mercè Capdevila, R. Dallinger, O. Zerbe: The Solution Structure and Dynamics of Cd-Metallothionein from Helix pomatia Reveal Optimization for Binding Cd over Zn. (2019) Biochemistry, 58, 470-4581.
R. Dallinger, O. Zerbe, C. Baumann, B. Egger, M. Capdevila, O. Palacios, R. Albalat, S. Calatayud, P. Ladurner, B. Schlick-Steiner, F. Steiner, V. Pedrini-Martha, R. Lackner, H. H. Lindner, M. Dvorak, M. Niederwanger, R. Schnegg and S. Atrian: Variable environmental cadmium levels through the last 445 million years have triggered convergent evolution of Cd-selective snail metallothioneins and their metal-specific diversification (2020) Metallomics, 12, 702.
R. Valsecchi, C. Baumann, A. Lila, O. Zerbe: Evolution of Cd2+ and Cu+ Binding in Helix pomatia Metallothioneins, Metallomics, 10 (2023), mfad057.