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Binding Of Alpha-Crystallin To Cortical And Nuclear Lens Lipid Membranes Derived From A Single Lens, Raju Timsina, Samantha Wellisch, Dieter Haemmerle, Laxman Mainali

Physics Faculty Publications and Presentations

Several studies reported that α-crystallin concentrations in the eye lens cytoplasm decrease with a corresponding increase in membrane-bound α-crystallin with age and cataracts. The influence of the lipid and cholesterol composition difference between cortical membrane (CM) and nuclear membrane (NM) on α-crystallin binding to membranes is still unclear. This study uses the electron paramagnetic resonance (EPR) spin-labeling method to investigate the α-crystallin binding to bovine CM and NM derived from the total lipids extracted from a single lens. Compared to CMs, NMs have a higher percentage of membrane surface occupied by α-crystallin and binding affinity, correlating with less mobility and …

Alpha-Crystallin Association With The Model Of Human And Animal Eye Lens-Lipid Membranes Is Modulated By Surface Hydrophobicity Of Membranes, Raju Timsina, Geraline Trossi-Torres, Jackson Thieme, Matthew O'Dell, Nawal K. Khadka, Laxman Mainali

Physics Faculty Publications and Presentations

Purpose

This research aims to probe the interaction of α-crystallin with a model of human, porcine, and mouse lens-lipid membranes.

Methods

Cholesterol/model of human lens-lipid (Chol/MHLL), cholesterol/model of porcine lens-lipid (Chol/MPLL), and cholesterol/model of mouse lens-lipid (Chol/MMLL) membranes with 0–60 mol% Chol were prepared using the rapid solvent exchange method and probe-tip sonication. The hydrophobicity near the surface of model lens-lipid membranes and α-crystallin association with these membranes were investigated using the electron paramagnetic resonance spin-labeling approach.

Results

With increased Chol content, the hydrophobicity near the surface of Chol/MHLL, Chol/MPLL, and Chol/MMLL membranes, the maximum percentage of membrane surface occupied …

Alpha-Crystallin-Membrane Association Modulated By Phospholipid Acyl Chain Length And Degree Of Unsaturation, Geraline Trossi-Torres, Raju Timsina, Laxman Mainali

Physics Faculty Publications and Presentations

α-crystallin-membrane association increases with age and cataracts, with the primary association site of α-crystallin being phospholipids. However, it is unclear if phospholipids’ acyl chain length and degree of unsaturation influence α-crystallin association. We used the electron paramagnetic resonance approach to investigate the association of α-crystallin with phosphatidylcholine (PC) membranes of different acyl chain lengths and degrees of unsaturation and with and without cholesterol (Chol). The association constant (K_a) of α-crystallin follows the trends, i.e., K_a (14:0–14:0 PC) > K_a (18:0–18:1 PC) > K_a (18:1–18:1 PC) ≈ K_a (16:0–20:4 PC) where the presence of Chol decreases K …