title: Ni(II) and Cu(II) binding with a 14-aminoacid sequence of Cap43 protein, TRSRSHTSEGTRSR.
abstract: The tetradecapeptide containing the 10 aminoacid repeated sequence on the C-terminus of the Ni(II)-induced Cap43 protein, was analyzed for Ni(II) and Cu(II) binding. A combined pH-metric and spectroscopic UV-VIS, EPR, CD and NMR study of Ni(II) and Cu(II) binding to the blocked CH3CO-Thr-Arg-Ser-Arg-Ser-His-Thr-Ser-Glu-Gly-Thr-Arg-Ser-Arg-NH2 (Ac-TRSRSHTSEGTRSR-Am) peptide, modeling a part of the C-terminal sequence of the Cap43 protein, revealed the formation of octahedral complexes involving imidazole nitrogen of histidine, at pH 5.5 and pH 7 for Cu(II) and Ni(II), respectively; a major square planar 4N-Ni(II) complex (about 100% at pH 9, log K* = -28.16) involving imidazole nitrogen of histidine and three deprotonated amide nitrogens of the backbone of the peptide was revealed; a 3N-Cu(II) complex (maximum about 70% at pH 7, log K*=-13.91) and a series of 4N-Cu(II) complexes starting at pH 5.5 (maximum about 90% at pH 8.7, log K* = -21.39 for CuH(-3)L), were revealed. This work supports the existence of a metal binding site at the COOH-terminal part of the Cap43 peptide.
authors.affiliation: Department of Chemistry, University of Sassari, Italy. zoroddu@ssmain.uniss.it
authors.forename: M A
authors.initials: MA
authors.lastname: Zoroddu
authors.forename: T
authors.initials: T
authors.lastname: Kowalik-Jankowska
authors.forename: H
authors.initials: H
authors.lastname: Kozlowski
authors.forename: K
authors.initials: K
authors.lastname: Salnikow
authors.forename: M
authors.initials: M
authors.lastname: Costa
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D018797:Cell Cycle Proteins; D002942:Circular Dichroism; D003300:Copper / Q000378:metabolism / Q000633:toxicity; D066298:In Vitro Techniques; D047908:Intracellular Signaling Peptides and Proteins; D009682:Magnetic Resonance Spectroscopy; D009532:Nickel / Q000378:metabolism / Q000633:toxicity; D010446:Peptide Fragments / 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; D003300:Copper; D047908:Intracellular Signaling Peptides and Proteins; D009532:Nickel; D010446:Peptide Fragments; D011506:Proteins; D000099259:N-myc Downstream-Regulated Gene 1 Protein