Cu(II)-Protamine interaction. I. The formation and structure of Cu(II)-clupeine Z complexes

Flower-like Cu9S8 nanocatalysts with highly active sites for synergistic NIR-II photothermal therapy and chemodynamic therapy

Chemodynamic therapy (CDT) is a promising reactive oxygen species-based therapeutic strategy for tumor therapy. However, the poor reaction kinetics of CDT agents severely restricts its further application. Herein, protamine stabilized flower-like Cu₉S₈ (PS@Cu₉S₈) nanocatalysts are fabricated via a one-pot biomineralization strategy for synergistic second near-infrared (NIR-II) photothermal therapy (PTT) and CDT of tumor. The PS@Cu₉S₈ nanocatalysts possess a high surface area (40.10 m² g^-1), which is higher than those of the previously reported solid and hollow copper sulfide nanoparticles. The high surface area of PS@Cu₉S₈ nanocatalysts increases the number of active sites during the Fenton-like reaction, thereby accelerating the efficiency of CDT. Meanwhile, the PS@Cu₉S₈ nanocatalysts show a high extinction coefficient (21.41 L g^-1 cm^-1) and photothermal conversion efficiency (42.34%), which results in an outstanding PTT efficiency and facilitate ˙OH generation for CDT. Furthermore, RNA-sequencing unveils the whole-genome expression change of 4T1 cells after PS@Cu₉S₈ nanocatalyst treatment, revealing the apparent changes in ROS, cell cycle, and apoptosis-related pathways. In vivo experiments proved the good therapeutic efficiency and negligible systematic toxicity of PS@Cu₉S₈ nanocatalysts. This work not only develops a superior multifunctional nanocatalyst for synergistic PTT and CDT of tumor, but also provides a facile approach to construct high-performance agents for cancer therapy.

A circular dichroic study of Cu(II) binding to bovine alpha-lactalbumin

The visible and ultraviolet circular dichroic spectra resulting from the interaction of bovine alpha-lactalbumin with successive Cu(II) ions have been recorded under a variety of conditions. Analysis of the observed change-transfer and d-d band transitions can be made in terms of two kinds of binding sites: at a histidyl group and at the N-terminal amino group, respectively. At basic pH the amide nitrogens of the peptide backbone progressively take part in the coordination. The occupation of the high affinity calcium binding site by Ca(II) and Mn(II) does not influence the Cu(II) binding process, suggesting that there is no direct interaction between this site and the Cu(II) binding sites.