Copper(II) complexes of alloferon 1 with point mutations (H1A) and (H9A) stability structure and biological activity

• Published in: Journal of inorganic biochemistry 2014-09, Vol.138, p.99-113
• Main Authors: Matusiak, Agnieszka, Kuczer, Mariola, Czarniewska, Elżbieta, Rosiński, Grzegorz, Kowalik-Jankowska, Teresa
• Format: Article
• Language: English
• Subjects: Alloferon; Amino Acid Sequence; Animals; Apoptosis; Apoptosis - drug effects; Biological activity; Coordination Complexes - chemistry; Coordination Complexes - pharmacology; Copper; Copper - chemistry; Drug Stability; Heart - drug effects; Hemocytes - drug effects; Hemocytes - pathology; Histidine - chemistry; Male; Mono- and polynuclear complexes; Monophenol Monooxygenase - biosynthesis; Organometallic Compounds - pharmacology; Peptides - genetics; Peptides - pharmacology; Point Mutation; Tenebrio - drug effects; Tenebrio - enzymology
• ISSN: 0162-0134; 1873-3344
• DOI: 10.1016/j.jinorgbio.2014.05.012

Mono- and polynuclear copper(II) complexes of the alloferon 1 with point mutations (H1A) A1GVSGH6GQH9GVH12G (Allo1A) and (H9A) H1GVSGH6GQA9GVH12G (Allo9A) have been studied by potentiometric, UV–visible, CD, EPR spectroscopic and mass spectrometry (MS) methods. To obtain a complete complex speciation different metal-to-ligand molar ratios ranging from 1:1 to 4:1 for Allo1A and to 3:1 for Allo9A were studied. The presence of the His residue in first position of the peptide chain changes the coordination abilities of the Allo9A peptide in comparison to that of the Allo1A. Imidazole-N3 atom of N-terminal His residue of the Allo9A peptide forms stable 6-membered chelate with the terminal amino group. Furthermore, the presence of two additional histidine residues in the Allo9A peptide (H6,H12) leads to the formation of the CuL complex with 4N {NH2,NIm–H1,NIm–H6,NIm–H12} binding site in wide pH range (5–8). For the Cu(II)–Allo1A system, the results demonstrated that at physiological pH7.4 the predominant complex the CuH−1L consists of the 3N {NH2,N−,CO,NIm} coordination mode. The inductions of phenoloxidase activity and apoptosis in vivo in Tenebrio molitor cells by the ligands and their copper(II) complexes at pH7.4 were studied. The Allo1A, Allo1K peptides and their copper(II) complexes displayed the lowest hemocytotoxic activity while the most active was the Cu(II)–Allo9A complex formed at pH7.4. The results may suggest that the N-terminal-His1 and His6 residues may be more important for their proapoptotic properties in insects than those at positions 9 and 12 in the peptide chain. Characterization of the Cu(II) complexes with alloferon 1 mutants Allo1A and Allo9A by means of potentiometry, CD, UV–Vis and EPR spectroscopic techniques, and ESI-MS spectrometry is reported. The biological studies are also performed. [Display omitted]