STUDIES ON THE ZN-CONTAINING S14 RIBOSOMAL-PROTEIN FROM THERMUS-THERMOPHILUS

The S14 ribosomal protein from the thermophilic organism Thermus therm ophilus, which contains a zinc-finger-like motif, namely -C-X-2-C-X-12 -C-X-2-C- [Tsiboli, P. & Choli, T. (1995) Biol. Chem. Hoppe-Seyler 376 , 127-130], has been overproduced, purified and investigated for its z inc content. According to atomic absorption experiments, the protein c ontains zinc at a molar ratio of one. Denaturation experiments with si multaneous use of denaturing and chelating agents (guanidine hydrochlo ride and EDTA), as well as renaturation experiments, have shown both t hat Zn is strongly bound to the protein and with 1:1 Zn/protein stoich eiometry. These findings provide very strong evidence in support of th e participation of the zinc-finger motif and the Zn in the formation o f a zinc-finger domain.