The crystal structure of Cd,Zn metallothionein isoform II from rat liver has been determined using the anomalous scattering data from five Cd in the native protein. The structure of a 4Cd cluster was solved by direct methods. A 2.3 A resolution electron density map was calculated by an iterative solvent leveling and map inversion procedure. The structure is folded into two domains. The N-terminal domain (beta) of residues 1-29 enfolds a three-metal cluster of 1 Cd and 2 Zn coordinated by six terminal cysteine thiolate ligands and three bridging cysteine thiolates. The C-terminal domain (alpha) of residues 30-61 enfolds a 4Cd cluster coordinated by six terminal and five bridging cysteine thiolates. All seven metal sites have tetrahedral coordination geometry. The domains are roughly spherical, diameter 15-20 A; there is limited contact between domains. The folding of alpha and beta is topologically similar but with opposite chirality. Redundant, short cysteine-containing sequences have similar roles in cluster formation in both alpha and beta. The Cd1Zn2(cys)9 cluster is homologous with a 12 atom fragment of the Cd4(cys)11 cluster.
CITATION STYLE
Furey, W. F., Robbins, A. H., Clancy, L. L., Winge, D. R., Wang, B. C., & Stout, C. D. (1987). Crystal structure of Cd,Zn metallothionein. Experientia. Supplementum, 52, 139–148. https://doi.org/10.1007/978-3-0348-6784-9_7
Mendeley helps you to discover research relevant for your work.