Gold-Catalyzed C-S Aryl-Group Transfer in Zinc Finger Proteins.

Reaction of the Au-C N chelate [Au(bnpy)Cl ] with the full-length zinc finger (ZnF; ZnCys His) of HIV nucleocapsid protein NCp7 results in C-S aryl transfer from the Au organometallic species to a cysteine of the ZnF. The reaction is general and occurs even for finger 3 of the transcription factor Sp1, containing a ZnCys His coordination sphere. This reaction is the first demonstration of group transfer from a coordination compound to biologically important zinc fingers, and is especially noteworthy for the ZnCys His transcription factors. The work expands the corpus of organometallic species which can efficiently modify biomolecules through C-atom transfer. The electronic features of the gold compound leading to this unexpected reaction were explored by X-ray absorption spectroscopy.