Evaluation of the impact of non-synonymous single nucleotide polymorphisms of chicken hemopexin on HEME binding ability

다국어 초록 (Multilingual Abstract)

Hemopexin (HPX) is a plasma glycoprotein with a high affinity for heme, acting as a key antioxidant defense molecule against heme-induced oxidative stress. However, limited information is available on chicken HPX, particularly regarding genetic polymorphisms that may influence its biochemical properties. In this study, conserved motifs and post-translational modification sites were analyzed via Clustal Omega, NetNGlyc-1.0, and NetPhos-3.1. Along with that, non-synonymous single-nucleotide polymorphisms (nsSNPs), which were indicated as deleterious within the chicken HPX gene, were identified from the Ensembl genome database. The threedimensional structure of wild-type and mutant HPX proteins was modeled using AlphaFold3, and their interactions with the HEME ligand were evaluated through HADDOCK 2.4 and PRODIGY binding affinity prediction. The results show that high conservation of histidine residues is essential for HEME binding. Four N-glycosylation and twenty-four phosphorylation sites were predicted, suggesting regulatory complexity in HPX function. Among the identified nsSNPs, mutations such as L414T and A349V exhibited enhanced predicted binding affinities (ΔG = -13.35 and -13.33 kcal/mol, respectively) compared to the wild type (ΔG = -13.17 kcal/ mol). Therefore, for the variants in this study, which are located in the C-terminal β-propeller domain, some may not affect heme binding, while others may enhance heme binding. In conclusion, this study provides interesting insight for future research on HPX polymorphisms as potential biomarkers for oxidative stress resistance and selection markers in poultry production.