Solution NMR characterization of Sgf73(1–104) indicates that Zn ion is required to stabilize zinc finger motif

Zinc finger motif contains a zinc ion coordinated by several conserved amino acid residues. Yeast Sgf73 protein was identified as a component of SAGA (Spt/Ada/Gcn5 acetyltransferase) multi-subunit complex and Sgf73 protein was known to contain two zinc finger motifs. Sgf73(1–104), containing the first zinc finger motif, was necessary to modulate the deubiquitinase activity of SAGA complex. Here, Sgf73(1–104) was over-expressed using bacterial expression system and purified for solution NMR (nuclear magnetic resonance) structural studies. Secondary structure and site-specific relaxation analysis of Sgf73(1–104) were achieved after solution NMR backbone assignment. Solution NMR and circular dichroism analysis of Sgf73(1–104) after zinc ion removal using chelation reagent EDTA (ethylene-diamine-tetraacetic acid) demonstrated that zinc ion was required to maintain stable conformation of the zinc finger motif.