| Inhibition of HIV and tumor-related protein functions have been linked to zinc removal from zinc finger proteins using transition metal complexes. The complex bis(O-ethyl-L-cysteinato)zinc(II), (cysE)2Zn, was synthesized to mimic the N2S2Zn coordination in zinc fingers to determine the effect of exogenous metals such as nickel and the mechanism of exchange. Addition of NiCl2 to (cysE)2Zn results in a notable color change. Absorptions at 302 nm, 382 nm, and 506 nm indicate replacement of zinc with nickel. Also several aggregates including [(cysE)4Ni3]2+ and [(cysE)3Ni 2]+ were identified by ESI-Mass Spectrometry. (cysE) 2Ni displays oxygen sensitivity, but the products from exchange studies do not. Oxygen-purged (cysE)2Ni slurries experience a distinct color change, and IR peaks at 1010 cm-1 and 1230 cm -1 from reactions in methanol indicate the formation of sulfones. A transesterification reaction led to a crystal structure of (cysM)2 Ni with average bond lengths of Ni-N: 1.95 A and Ni-S: 2.19 A. |
