Hydrophobic forces at play: insights into AmelOBP4 and brood volatile interactions in Apis mellifera hygienic behavior

Understanding the intricate processes underlying olfaction necessitates unraveling the complexities of odorant binding protein's interactions with volatile compounds triggering hygienic behavior in Apis mellifera, This study delves into the intricate processes of olfaction by focusing on the interactions between Apis mellifera Odorant Binding Protein 4 (AmelOBP4) and volatile compounds associated with hygienic behavior, employing a comprehensive computational approach. Molecular docking analyses reveal detailed binding interactions, emphasizing the significance of hydrophobic interactions and specific amino acid residues in stabilizing AmelOBP4-volatile complexes, notably with 2-nonacosanone (-8.4 kcal/mol) and hexacosyl acetate (-8.4 kcal/mol). Molecular dynamics simulations demonstrate sustained stability and principal component analysis affirms structural integrity through restricted global motions. Binding free energy calculations underscore robust interactions, with per-residue free energy decomposition identifying key amino acids contributing significantly to binding affinity. These findings illuminate the pivotal role of hydrophobic interactions and specific residues (Phe 60, Leu 83, Ile 116, Leu 126, and Leu 130) in modulating AmelOBP4-volatile interactions, providing foundational insights into volatile-based applications and potential olfactory response modulation, contributing to our understanding of olfactory processes.