Comparative analysis of the interaction of allure red with hemoglobin and myoglobin

Abstract

Studying the interaction between hemoglobin (Hb) and myoglobin (Mb) with allure red (AR) has important implications for the safe use of pigments. Extensive multi-fluorescence and thermodynamic (Ksv) analyses revealed that static quench, spontaneous binding processes were predominantly driven by van der Waals forces. At 37°C, the binding constant (Ka) was 0.55×104 (L/mol) compared with 0.22×104 (L/mol) for AR to Mb. AR has a greater effect on the secondary structure of Mb and remarkable α-helix changes. Notably, docking and molecular dynamic simulations indicated that AR is bonding in the hydrophobic cavity of Hb and in the active region of Mb, and that hydrophobic forces primarily drive the binding of AR to Hb and Mb. LEU100, LEU104, HIS103 and, HIS64, HIS24, LEU69, LEU104, LIE142 are the major contributors to AR to Hb Mb binding. Moreover, greater fluctuation in RMSD values indicate conformational changes in AR to Mb. Rg results demonstrated a tighter structure in AR to Hb and a looser structure in AR to Mb compared with the unbound proteins.