Cholesterol and Q147E Deamidation Modulates αA-Crystallin Membrane Binding Elucidating Protective Role of Lens Membrane Composition Changes With Aging

In Chol-free membranes, the deamidated Q147E-αAc binds significantly more to the POPC membranes compared to WT, whereas WT binds significantly more to the SM membranes compared to Q147E-αAc. In contrast, for 33 mol% Chol-containing membranes, the deamidated Q147E-αAc binds significantly more to POPC and SM membranes than WT. Conversely, 60 mol% Chol-containing membranes completely inhibit WT and deamidated Q147E-αAc binding to POPC and SM membranes. These results suggest that increased Chol content of the lens membranes during aging protects against accumulation of modified proteins on the membrane associated with cataracts.