Amino Acid Complexation Fractionates Nickel Isotopes: Implications for Tracing Nickel Cycling in the Environment.

ABSTRACT: Nickel (Ni) is an essential cofactor in many proteins. Ni stable isotopes have been shown to undergo isotope fractionation in microorganisms and plants. However, the mechanisms driving this fractionation are poorly understood. Here, we present experimental data on Ni isotope fractionation during binding by common Ni-binding amino acids: glutamate (carboxylate side chain), histidine (imidazole side chain), and cysteine (sulfhydryl side chain). We used an equilibrium Donnan dialysis approach to separate free versus bound Ni and measured the isotopic composition of both pools via multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). Our results reveal that the glutamate and cysteine favor heavy ⁶⁰Ni (Δ^60/58Ni_glutamate = +0.80 ± 0.08; Δ⁶

SUBMITTER: Selden CR 

PROVIDER: S-EPMC11905280 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature