Further characterization of the N-terminal copper(II)- and nickel(II)-binding motif of proteins. Studies of metal binding to chicken serum albumin and the native sequence peptide

Abstract

We have investigated the Cu(II)- and Ni(II)-binding properties of chicken serum albumin (CSA) and of the native sequence tripeptide derived from the N-terminus of this protein. Spectrophotometric and equilibrium dialysis experiments demonstrate that Cu(II) and Ni(II) bind non-specifically at the N-terminus of CSA. Proton displacement studies show that the histidine residue in the fourth position of the protein does not appear to participate in the binding of the two metals. Consistent results were obtained with the native sequence tripeptide L-aspartyl-L-alanyl-L-glutamic acid N-methylamide. The results presented here demonstrate that neither the glutamic acid residue in the third position nor the histidine in the fourth position participate in the binding of Cu(II) and Ni(II) to CSA. It is known, however, that a number of other albumins with a histidine residue in the third position possess high-affinity Cu(II)- and Ni(II)-binding sites. Our results provide further evidence that the N-terminal Cu(II)/Ni(II)-binding motif requires a histidine at the third position in order to bind Cu(II) and Ni(II) specifically.

Culinary Biophysics: on the Nature of the 6X°C Egg

“…14,15 The peak denaturation temperature of BSA using differential scanning calorimetry (DSC) is found at ∼60°C depending on the conditions used, 16 although the secondary structure starts to be lost permanently above 50°C. 17 The good gelation ability of BSA has long been established, 18 and it is known to form gels at <60°C.…”

Nickel Ion Complexes of Amino Acids and Peptides

“…Analogous N-terminal sequences, containing histidine in the third position (Xx-Yy-His), are known for their specifi city for Cu(II) and Ni(II) binding [18]. They are also present in several human peptide hormones and proteins, human serum albumin (HSA) being the most prominent [160]. The Asp-Ala-His sequence of HSA is the physiological carrier of Cu(II) [161], and it is also involved in nickel toxicity, providing the antigen for nickel allergy when coordinated to Ni(II) [162].…”

Low salinity enhances NI-mediated oxidative stress and sub-lethal toxicity to the green shore crab (Carcinus maenas)

“…Ni has a high affinity for such histidine residues (e.g. Predki et al, 1992), which play an important role in CAT catalytic activity (Mate et al, 1999). CAT activity decreases were also observed in the euryhaline killifish where FW gills displayed a significant decrease in CAT compared to 100% SW gills, indicating again the sensitivity at lower salinities.…”