title: Coordination Environment of Cu(II) Ions Bound to N-Terminal Peptide Fragments of Angiogenin Protein.
abstract: Angiogenin (Ang) is a potent angiogenic factor, strongly overexpressed in patients affected by different types of cancers. The specific Ang cellular receptors have not been identified, but it is known that Ang-actin interaction induces changes both in the cell cytoskeleton and in the extracellular matrix. Most in vitro studies use the recombinant form (r-Ang) instead of the form that is normally present in vivo ("wild-type", wt-Ang). The first residue of r-Ang is a methionine, with a free amino group, whereas wt-Ang has a glutamic acid, whose amino group spontaneously cyclizes in the pyro-glutamate form. The Ang biological activity is influenced by copper ions. To elucidate the role of such a free amino group on the protein-copper binding, we scrutinized the copper(II) complexes with the peptide fragments Ang(1-17) and AcAng(1-17), which encompass the sequence 1-17 of angiogenin (QDNSRYTHFLTQHYDAK-NH₂), with free amino and acetylated N-terminus, respectively. Potentiometric, ultraviolet-visible (UV-vis), nuclear magnetic resonance (NMR) and circular dichroism (CD) studies demonstrate that the two peptides show a different metal coordination environment. Confocal microscopy imaging of neuroblastoma cells with the actin staining supports the spectroscopic results, with the finding of different responses in the cytoskeleton organization upon the interaction, in the presence or not of copper ions, with the free amino and the acetylated N-terminus peptides.
authors.affiliation: Institute of Biostructures and Bioimages, National Council of Research ( CNR), Via P. Gaifami 18, 95126 Catania, Italy. leotony@unict.it.
authors.forename: Antonio
authors.initials: A
authors.lastname: Magrì
authors.affiliation: Department of Chemical Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy. alemunzy31@hotmail.it.
authors.forename: Alessia
authors.initials: A
authors.lastname: Munzone
authors.affiliation: Department of Chemistry and Pharmacy, University of Sassari, Via Vienna 2, 07100 Sassari, Italy. peana@uniss.it.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Peana
authors.affiliation: Department of Chemistry and Pharmacy, University of Sassari, Via Vienna 2, 07100 Sassari, Italy. sere@uniss.it.
authors.forename: Serenella
authors.initials: S
authors.lastname: Medici
authors.affiliation: Department of Chemistry and Pharmacy, University of Sassari, Via Vienna 2, 07100 Sassari, Italy. zoroddu@uniss.it.
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: Zoroddu
authors.affiliation: Department of Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9C, 41390 Göteborg, Sweden. orjan.hansson@chem.gu.se.
authors.forename: Orjan
authors.initials: O
authors.lastname: Hansson
authors.affiliation: Department of Chemical Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy. csatriano@unict.it.
authors.forename: Cristina
authors.initials: C
authors.lastname: Satriano
authors.affiliation: Institute of Biostructures and Bioimages, National Council of Research ( CNR), Via P. Gaifami 18, 95126 Catania, Italy. erizzarelli@unict.it.|Department of Chemical Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy. erizzarelli@unict.it.
authors.forename: Enrico
authors.initials: E
authors.lastname: Rizzarelli
authors.affiliation: Department of Pharmacy, University of Pisa, Via Bonanno Pisano 6, 56126 Pisa, Italy. lamendola@farm.unipi.it.
authors.forename: Diego
authors.initials: D
authors.lastname: La Mendola
mesh_terms: D001665:Binding Sites; D002470:Cell Survival / Q000187:drug effects; D002942:Circular Dichroism; D056831:Coordination Complexes / Q000494:pharmacology*; D003300:Copper / Q000737:chemistry / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009447:Neuroblastoma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D010446:Peptide Fragments / Q000494:pharmacology*; D011485:Protein Binding; D012259:Ribonuclease, Pancreatic / Q000737:chemistry / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D056831:Coordination Complexes; D010446:Peptide Fragments; D003300:Copper; C046366:angiogenin; D012259:Ribonuclease, Pancreatic
keywords: NMR; actin; angiogenesis; confocal microscopy; copper; neuroblastoma cells; peptidomimetic; recombinant protein; stability constants