Figure 1.

Primary structure of Cd₇‐MT from mussel MT‐10 and Cd‐thiolate connectivity in the two clusters. (a) Amino acid sequence of the α‐ and β‐domains,14a showing the 21 Cys residues (in yellow) and Cd₃Cys₉ and Cd₄Cys₁₂ clusters3b (in green). Cysteine represents 21/72=29 % of the total amino acids. The Cys residues are arranged in nine CXC, one CXXC, and five CXXXC motifs, where X can be any amino acid. The solid lines denote the Cd^II‐Cys bonds, and the dotted line indicates an ambiguous assignment between the Cys residues 1, 2, and 3 (only the last possibility is represented for clarity). The horizontal dashed line denotes the boundary between the two domains connected by a flexible linker segment of three amino acids (KVV). (b) Polyhedral representation of the connectivity of the Cd(Cys)₄ tetrahedra in each domain. The Cd₃Cys₉‐β cluster has three bridging (μ₂‐SR) and six terminal (μ‐SR) cysteinyl sulfur atoms, and the Cd₄Cys₁₂‐α cluster has four μ₂‐SR and eight μ‐SR.