ISBN: 978-83-60043-10-3 - eurobic9

Eurobic9, 2-6 September, 2008, Wrocław, Poland
P210. Interaction of Cap43 Protein Fragment with Ni(II) and Cu(II) Ions
M.A. Zoroddu a , M. Peana a , and S. Medici a , T. Kowalik-Jankowska b , H. Kozłowski b
a
Department of Chemistry, University of Sassari, Via Vienna 2, 07100, Sassari, Italy
e-mail: zoroddu@uniss.it
b
Faculty of Chemistry, University of Wrocław, 14 Joliot-Curie, 50-383 Wrocław, Poland
One of the research topics in our group is protein Cap 43, which seems directly related to the cellular response
after nickel exposure, [1, 2] as well as to a number of cancers.[1, 3] The studies we carried out for several years
started from a small peptide model of Cap 43 and were successively expanded to include a two-
(TRSRSHTSEG-TRSRSHTSEG) and a three-repeated (TRSRSHTSEG-TRSRSHTSEG-TRSRSHTSEG)
monohistidinic decapeptide fragment in its C-terminus.[4-6] Such 20- and 30-amino acid sequences were tested
for Ni(II)- and Cu(II)- coordination at different pH values, by both potentiometry and spectroscopic techniques
(NMR, EPR, UV-Vis, CD). The two metals showed a slightly different behaviour towards coordination, and the
interaction of Cu(II) ions with the two peptides started at pH values lower than those for Ni(II). What appeared
clear was that in both cases each 10-amino acid fragment TRSRSHTSEG was able to coordinate a single metal
ion to form a square planar 4N {4N} chromophore. The coordination mode involved an imidazole nitrogen from
the His residue, and the amidic nitrogens from His, Ser, and Arg. At high pH values, further deprotonations were
observed for the Cu(II) species.
References:
[1] D. Zhou, K. Salnikow, M. Costa; Cancer Res., 58, 2182 (1998)
[2] K. Salnikow, D. Zhou, T. Kluz, C. Wang, M. Costa, in: Metal and Genetics, (Sarkar Bed), New York, 131
(1999)
[3] K. Salnikow, T. Kluz, M. Costa, Toxicol. Appl. Pharmacol., 160, 127 (1999)
[4] M.A. Zoroddu, T. Kowalik-Jankowska, H. Kozlowski, K. Salnikow, M. Costa, J. Inorg. Biochem., 84, 47
(2001)
[5] M.A. Zoroddu, M. Peana, T. Kowalik-Jankowska, H. Kozlowski, M. Costa, J. Chem. Soc. Dalton Trans., 458
(2002)
[6] M.A. Zoroddu, M. Peana, T. Kowalik-Jankowska, H. Kozlowski, M. Costa, J. Inorg Biochem., 98, 931
(2004)
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