title: Nickel(II) binding to Cap43 protein fragments.
abstract: Cap43 protein has been tested for metal binding domains. The protein, specifically induced by nickel compounds in cultured human cells, had a new mono-histidinic motif consisting of 10 amino acids repeated three times in the C-terminus. The 20-Ac-TRSRSHTSEG-TRSRSHTSEG (Thr(341)-Arg-Ser-Arg-Ser-His(346)-Thr-Ser-Glu-Gly-Thr-Arg-Ser-Arg-Ser-His(356)-Thr-Ser-Glu-Gly(360) - peptide 1) and the 30-Ac-TRSRSHTSEG-TRSRSHTSEG-TRSRSHTSEG (Thr(341)-Arg-Ser-Arg-Ser-His(346)-Thr-Ser-Glu-Gly-Thr-Arg-Ser-Arg-Ser-His(356)-Thr-Ser-Glu-Gly-Thr-Arg-Ser-Arg-Ser-His(366)-Thr-Ser-Glu-Gly(370) - peptide 2) amino acids sequence has been analyzed as a site for Ni(II) binding. A combined pH-metric and spectroscopic (UV-visible, CD, NMR) studies of Ni(II) binding to both fragments were performed. The 20-amino acid peptide can bind one and two metal ions while the 30-amino acid fragment one, two and three metal ions. At physiological pH, depending on the metal to ligand molar ratio, peptide 1 forms the Ni(2)L species while peptide 2 the NiL, Ni(2)L and Ni(3)L complexes where each metal ion is coordinated to the imidazole nitrogen atom of the histidine residue of the 10-amino acid fragment. Octahedral complexes at pH 8-9 and planar 4N complexes with (N(Im), 3N(-)) bonding mode at pH above 9, are formed. This work supports the existence of an interesting binding site at the COOH-terminal domain of the Cap43 protein.
authors.affiliation: Department of Chemistry and Pharmacy Faculty, University of Sassari, Via Vienna 2, 07100 Sassari, Italy. zoroddu@uniss.it
authors.forename: M A
authors.initials: MA
authors.lastname: Zoroddu
authors.forename: M
authors.initials: M
authors.lastname: Peana
authors.forename: T
authors.initials: T
authors.lastname: Kowalik-Jankowska
authors.forename: H
authors.initials: H
authors.lastname: Kozlowski
authors.forename: M
authors.initials: M
authors.lastname: Costa
mesh_terms: D020816:Amino Acid Motifs; D018797:Cell Cycle Proteins; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D009532:Nickel / Q000737:chemistry* / Q000378:metabolism; D009842:Oligopeptides / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D000099259:N-myc Downstream-Regulated Gene 1 Protein
chemical_list: D018797:Cell Cycle Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009532:Nickel; D009842:Oligopeptides; D011506:Proteins; D000099259:N-myc Downstream-Regulated Gene 1 Protein