Coordination of Cu(2+)and Ni(2+) with the histone model peptide of H2B N-terminal tail (1-31 residues): A spectroscopic study.
The interaction of Cu(2+) and Ni(2+) with the N-terminal tail of histone H2B, the 31 amino acid peptide H2B(1-31) (Ac-PEPAKSAPAPKKG(13)SKKAVTKAQKKD(25)GKKRKR-NH(2)), studied by various spectroscopic techniques (UV/Vis, CD, EPR and NMR) are described. The results showed the formation of Cu(2+)-H2B(1-31) complexes above pH 7.3 most probably through the beta-carboxylate group of D25. With the increase of the pH, a mixture of 3 N and 4 N species presenting {2N(-), CO, epsilonNH(2)} and {2N(-), OH(2), epsilonNH(2)}{epsilonNH(2)} coordination modes, respectively is formed, while at highly basic solutions the binding of an additional amide donor is suggested. NMR spectroscopy supported by CD spectroscopy indicated that Ni(2+) coordination takes place most likely through Q22-K23-K24-D25 peptide fragment. Direct coordination to Ni(2+), in a {4N(-)} coordination mode, with a severe conformation change in all residues from G13 to G26 was observed. Cu(2+) and Ni(2+) binding to the N-terminal tail of H2B causes a severe conformational change that might interfere with histone post-translational modifications, possibly leading to epigenetic changes.
Nunes
Ana Mónica
AM
University of Ioannina, Department of Chemistry, 45110, Ioannina, Greece.
Zavitsanos
Kimon
K
Malandrinos
Gerasimos
G
Hadjiliadis
Nick
N
D000595:Amino Acid Sequence; D001665:Binding Sites; D002942:Circular Dichroism; D003300:Copper / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D006657:Histones / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009532:Nickel / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular; D017434:Protein Structure, Tertiary; D013056:Spectrophotometry, Ultraviolet
D006657:Histones; D003300:Copper; D009532:Nickel