Cap43 has been reported to be specifically induced by nickel compounds in a variety of cell lines. Although the function of the Cap43 protein (MW 43,000) is not clear, it does appear to be induced in response to an increase in intracellular concentration of Ca2+, caused by nickel ion exposure in cultured human cells, for this reason it is name Cap43:Calcium protein 43,000. Cap43 protein is commonly expressed at low levels in normal tissues, but it is overexpressed in a variety of cancer cells. The high level of expression in a cancerous status combined with the elevated stability of Cap43 protein makes it an excellent cancer marker. A possible way to better understand the molecular mechanisms implicated in toxicity and carcinogenicity of nickel compounds is to study the characteristics of the proteins expressed by the genes specifically induced by these carcinogens. For this reason we focused our attention to investigate the interaction ability of nickel to Cap43 protein. The peculiarity of Cap43 is its new mono-histidinic motif consisting of ten amino acids (TRSRSHTSEG) repeated three times in the C-terminus. We have analyzed, for NI(II) binding, the 30-amino acid C-terminal sequence of the protein, TRSRSHTSEG-TRSRSHTSEG-TRSRSHTSEG, by the use of different NMR techniques such as 1D, NOESY, TOCSY and ROESY experiments. Our results support the existence of an interesting binding site for Ni(II) at the C-terminal domain of Cap43 protein.
Nickel Binding to Cap43 Protein: an NMR Study / Zoroddu, Maria Antonietta; Peana, Massimiliano Francesco; Medici, Serenella. - (2006), pp. 213-213. ((Intervento presentato al convegno “9th International Symposium on Metal Ions in Biology and Medicine” tenutosi a Lisboa, Portugal nel 21-24 Maggio 2006.