To elucidate the three-dimensional solution structure of yeast copper-metallothionein (MT) from Saccharomyces cerevisiae, silver-substituted yeast metallothionein has been prepared as an isomorphic, NMR active, metal ion derivative. Using Ag-MT, 1H-109Ag heteronuclear multiple quantum coherence transfer (HMQC) experiments have been performed to identify the individual109Ag resonances and their associated cysteine ligands, respectively. Specific factors associated with the optimized execution of the 1H-105Ag HMQC experiments are identified and discussed. Analysis of the HMQC data has established the specific connectivities between 10 of the 12 cysteine residues and seven bound 109Ag(I) metal ions. The data confirm the exclusive involvement of cysteine thiolates in metal coordination and indicate that a minimum of eight cysteines are involved as bridging, shared ligands. Additionally, the present data suggest the existence of a mixed coordination number (2 and 3) for the seven bound Ag(I) ions.