Protein Structural Modeling Explains Rapid Oxidation in Poultry and Fish Myoglobins Compared to Livestock Myoglobins

Background: This study aimed to investigate rapid oxidation in poultry and fisQh myoglobin compared to livestock myoglobin using protein structural differences and bioinformatics tools. Methods: Myoglobins from beef (Bos taurus), bison (Bos bison), sheep (Ovis aries), goat (Capra hircus), red deer (Cervus elaphus), pork (Sus scrofa), chicken (Gallus gallus), turkey (Meleagris gallopavo), yellowfin tuna (Thunnus albacares), and tilapia (Oreochromis niloticus) were analyzed to understand differences in structure and function that may influence oxidative behavior. Results: Fish and poultry had shorter or absent D-helix in their myoglobin structure than other species. Tilapia showed the largest heme cavity surface area, indicating significant internal void space, while yellowfin tuna had the largest heme cavity volume, which could affect ligand binding dynamics compared with poultry and other livestock species. However, the heme solvent-accessible area was greater in chicken and turkey than in fish and other livestock species. Tuna myoglobin contains a cysteine and fish myoglobins have fewer amino acids compared to other species. Limited knowledge is currently available on the effects of proteoform, especially post-translational modifications, on the oxidation of myoglobin from different species. Conclusions: The bioinformatics approach used in this study suggests that, in addition to physiological reasons, shorter D-helix, larger heme cavity in tilapia and yellowfin tuna, and greater solvent-accessible area in poultry contribute to increased oxidation in myoglobin from poultry and fish compared with myoglobin from livestock species.