RYBP (Ring1A and YY1 binding protein) is a zinc finger protein with an essential role during embryonic development, which binds transcriptional factors, Polycomb products, and mediators of apoptosis, suggesting roles in, apparently,...
moreRYBP (Ring1A and YY1 binding protein) is a zinc finger protein with an essential role during embryonic development, which binds transcriptional factors, Polycomb products, and mediators of apoptosis, suggesting roles in, apparently, unrelated functions. To investigate mechanisms underlying its association with functionally diverse partners, we set out to study its structural properties using a number of biophysical (fluorescence, circular dichroism, Fourier transform infrared, and NMR spectroscopies) and hydrodynamic (analytical ultracentrifugation, DOSY-NMR, and gel filtration chromatography) techniques. We find RYBP to be a noncompact protein with little residual secondary structure, lacking a well-defined tertiary structure. These observations are also supported by theoretical calculations using neural networks and pairwise energy content, suggesting that RYBP is a natively unfolded protein. In addition, structural studies on its binding to the C-terminal region of the Polycomb p...