113Cd NMR Experiments Reveal an Unusual Metal Cluster in the Solution Structure of the Yeast Splicing Protein Bud31p

Establishing the binding topology of structural zinc ions in proteins is an essential part of their structure determination by NMR spectroscopy. Using ¹¹³Cd NMR experiments with ¹¹³Cd‐substituted samples is a useful approach but has previously been limited mainly to very small protein domains. Here we used ¹¹³Cd NMR spectroscopy during structure determination of Bud31p, a 157‐residue yeast protein containing an unusual Zn₃Cys₉ cluster, demonstrating that recent hardware developments make this approach feasible for significantly larger systems.