Discovery of novel calcium-chelating peptides from Antarctic krill: Structural elucidation and dynamic coordination
Chaozhong Fan1, Yang Liu1, Tingting Yang1
1State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, No.1299, Sansha Road, Qingdao, Shandong Province 266404, PR China.
Abstract:
Calcium-chelating peptides (CCPs) represent promising strategies for addressing calcium deficiency, yet their chelating mechanisms require further elucidation. This study identified two novel CCPs, EEDLER and IVELEEE, from Antarctic krill through enzymatic hydrolysis combined with multi-step separation and purification, exhibiting calcium-chelating capacities of 12.1 ± 1.3 μg/mg and 5.1 ± 0.5 μg/mg, respectively. Comprehensive characterization was performed using molecular dynamics simulation, molecular docking, Fourier transform infrared spectroscopy, and isothermal titration calorimetry. Results demonstrated that acidic amino acids played a dominant role in calcium coordination, while hydrophobic amino acids also influenced calcium chelation efficiency. Calcium primarily formed coordinate bonds with carboxyl oxygen and carbonyl oxygen of the peptide chain, achieving dynamic multi-site coordination through bidentate/multidentate modes. Additionally, calcium chelation enhanced conformational orderliness and stability of the peptide chain. This study provides molecular mechanistic insights for the development of novel calcium supplements.
