TY - JOUR
T1 - Alpha-Crystallin-Membrane Association Modulated by Phospholipid Acyl Chain Length and Degree of Unsaturation
AU - Trossi-Torres, Geraline
AU - Timsina, Raju
AU - Mainali, Laxman
N1 - Publisher Copyright:
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2022/5/1
Y1 - 2022/5/1
N2 - 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 a for all membranes. With an increase in α-crystallin concentration, the saturated and monounsaturated membranes rapidly become more immobilized near the headgroup regions than the polyunsaturated membranes. Our results directly correlate the mobility and order near the headgroup regions of the membrane with the K a , with the less mobile and more ordered membrane having substantially higher K a . Furthermore, our results show that the hydrophobicity near the headgroup regions of the membrane increases with the α-crystallin association, indicating that the α-crystallin-membrane association forms the hydrophobic barrier to the transport of polar and ionic molecules, supporting the barrier hypothesis in cataract development.
AB - 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 a for all membranes. With an increase in α-crystallin concentration, the saturated and monounsaturated membranes rapidly become more immobilized near the headgroup regions than the polyunsaturated membranes. Our results directly correlate the mobility and order near the headgroup regions of the membrane with the K a , with the less mobile and more ordered membrane having substantially higher K a . Furthermore, our results show that the hydrophobicity near the headgroup regions of the membrane increases with the α-crystallin association, indicating that the α-crystallin-membrane association forms the hydrophobic barrier to the transport of polar and ionic molecules, supporting the barrier hypothesis in cataract development.
KW - association constant
KW - degree of unsaturation
KW - mobility parameter
KW - phospholipid acyl chain length
KW - physical properties of membranes
KW - α-crystallin
UR - https://scholarworks.boisestate.edu/physics_facpubs/250
M3 - Article
AN - SCOPUS:85129729623
JO - Physics Faculty Publications and Presentations
JF - Physics Faculty Publications and Presentations
ER -