The solution structure of ZNF593 from Homo sapiens reveals a zinc finger in a predominately unstructured protein

Here, we report the solution structure of ZNF593, a protein identified in a functional study as a negative modulator of the DNA‐binding activity of the Oct‐2 transcription factor. ZNF593 contains a classic C 2 H 2 zinc finger domain flanked by about 40 disordered residues on each terminus. Although the protein contains a high degree of intrinsic disorder, the structure of the zinc finger domain was resolved by NMR spectroscopy without a need for N‐ or C‐terminal truncations. The tertiary structure of the zinc finger domain is composed of a β‐hairpin that positions the cysteine side chains for zinc coordination, followed by an atypical kinked α‐helix containing the two histidine side chain ligands. The structural topology of ZNF593 is similar to a fragment of the double‐stranded RNA‐binding protein Zfa and the C‐terminal zinc finger of MBP‐1, a human enhancer binding protein. The structure presented here will provide a guide for future functional studies of how ZNF593 negatively modulates the DNA‐binding activity of Oct‐2, a POU domain‐containing transcription factor. Our work illustrates the unique capacity of NMR spectroscopy for structural analysis of folded domains in a predominantly disordered protein.