Copper and nickel binding in multi-histidinic peptide fragments

Phenol-oxidizing laccases from the termite gut☆

“…Given that most characterized laccases are from fungi, these findings are not overly surprising; i.e., the conditions within the R. flavipes gut are distinctly different than those encountered by free-living fungi (Brune et al, 1995a(Brune et al, , 1995b. The presence of His tags on the recombinant proteins is apparently responsible for additional Cu binding (Perrin, 1959;Aiba et al, 1974; Zoroddu et al, 2009), which results in RfLacA and B having 3e4 more Cu per protein molecule than typical native laccases, and potentially other activity characteristics like sodium azide enhancement and EDTA inhibition. Recombinant RfLacA and RfLacB were also found to require H 2 O 2 for activity (Fig.…”

“…This estimate includes the four predicted Cu molecules per laccase protein, plus one additional Cu molecule per Table S1 for sequence details and abbreviations. two histidines in the 6Â histidine tag (Perrin, 1959;Aiba et al, 1974;Zoroddu et al, 2009). Negligible amounts of Ca, Mn, or Zn were also detected (less than 1 atom per protein molecule).…”

Nickel(II) complexes of the multihistidine peptide fragments of human prion protein

“…It is widely accepted that the presence of histidyl residues significantly enhances the metal binding capacity of peptide molecules, but zinc(II) ions are generally not able to induce deprotonation and coordination of peptide amide residues [33]. On the contrary, nickel(II) induced deprotonation and binding of the main chain peptide amide groups is a common feature of peptide ligands and several examples of this coordination mode were reported for the terminally protected multihistidine peptides, too [34][35][36][37][38]. Similar observations have already been reported for several peptide fragments of prion protein and effective nickel(II) binding at His96 and His111 residues was suggested [39].…”

Conformationally Constrained Sequence Designs to Bias Monomer–Dimer Equilibriums in TASP Systems

“…A common metal ion chelation strategy employed by proteins (synthetic or natural) for structural stability and definition involves histidine motifs. [39][40][41][42][43] A potential histidine metal ion binding site that should support the helix dimer conformation was chosen based on the Q4 cavitein crystal dimer. The Q4 crystal structure is an asymmetric dimer, which creates some difficulty and uncertainty when choosing a metal ion binding site.…”