METAL-ION BINDING TO A ZINC-FINGER PEPTIDE-CONTAINING THE CYS-X-2-CYS-X-4-HIS-X-4-CYS DOMAIN OF A NUCLEIC-ACID BINDING-PROTEIN ENCODED BY THE DROSOPHILA FW-ELEMENT

The metal binding properties of a 18-residue zinc finger peptide conta ining a CCHC box which reproduces one of the cysteine-rich domains of a putative nucleic acid binding protein encoded by the Fw transposable element from Drosophila melanogaster were investigated through electr onic and H-1 NMR spectroscopy. Dissociation constants of 2(+/-1)x10(-1 2) M and 4(+/-1)x10(-7) M were determined for the Zn2+ and Co2+ adduct , respectively. These values are similar to those for other CCHC-pepti des investigated previously, although the length of the spacer between the second cysteine and the histidine apparently exerts some influenc e on the spectral properties and on the stability of the Co2+-peptide adduct. The 1H NMR spectrum of the present Co2+-derivative contains a number of well resolved hyperfine-shifted resonances between 350 and - 50 ppm which arise from the metal binding residues and nearby groups. These peaks can in principle be profitably exploited to monitor protei n-nucleic acid interactions. (C) 1998 Academic Press.