Dynamics of allosteric modulation of lymphocyte function associated antigen-1 closure-open switch: unveiling the structural mechanisms associated with outside-in signaling activation

To provide insight into the dynamics of the shape-shifting mechanistic events associated with the opening (activation) of Lymphocyte Function Associated Antigen-1 upon allosteric modulation by an activator, ICAM Binding Enhancer-667 (IBE-667), using molecular dynamics simulation. Various parameters were used to appropriately describe and understand the sequence of events that characterized its activation across the simulation period such as residual distances, TriC alpha angles; as well as the dihedral angle. Our findings revealed a significant residual fluctuation and stability difference between both systems. Also, there was a synergistic coordination of the active MIDAS site by the downward pull of the alpha 7 helix upon ligand binding, which appeared to be directly proportional to each other. Allosteric binding of IBE-667, activated LFA-1 integrin as evidenced by residual motion at the MIDAS region which appears to be synergistically coordinated by the downward pull of the alpha 7 helix.