STRUCTURE OF THE CARBOXY-TERMINAL LIM DOMAIN FROM THE CYSTEINE-RICH PROTEIN CRP

The three dimensional solution structure of the carboxy terminal LIM d omain of the avian Cysteine Rich Protein (CRP) has been determined by nuclear magnetic resonance spectroscopy. The domain contains two zinc atoms bound independently in CCHC (C=Cys, H=His) and CCCC modules. Bot h modules contain two orthogonally-arranged antiparallel beta-sheets, and the CCCC module contains an alpha-helix at its C terminus. The mod ules pack due to hydrophobic interactions forming a novel global fold. The structure of the C-terminal CCCC module is essentially identical to that observed for the DNA-interactive CCCC modules of the GATA-1 an d steroid hormone receptor DNA binding domains, raising the possibilit y that the LIM motif may have a DNA binding function.