Zinc-Binding Cysteines: Diverse Functions and Structural Motifs

Cysteine residues are known to perform essential functions within proteins, including binding to various metal ions. In particular, cysteine residues can display high affinity toward zinc ions (Zn(2+)), and these resulting Zn(2+)-cysteine complexes are critical mediators of protein structure, catalysis and regulation. Recent advances in both experimental and theoretical platforms have accelerated the identification and functional characterization of Zn(2+)-bound cysteines. Zn(2+)-cysteine complexes have been observed across diverse protein classes and are known to facilitate a variety of cellular processes. Here, we highlight the structural characteristics and diverse functional roles of Zn(2+)-cysteine complexes in proteins and describe structural, computational and chemical proteomic technologies that have enabled the global discovery of novel Zn(2+)-binding cysteines.