Biophysical Society Conference | Tahoe 2024

Molecular Biophysics of Membranes

Poster Abstracts

16-POS Board 14 MEMBRANES MEDIATED INHIBITION ON THE CHAPERONE ACTIVITY OF ALPHA-CRYSTALLINS Jui-Kai Chen 1 ; Jheng-Hao Lin 1 ; Yu-Ting Liu 1,2 ; Ming-Tao Lee 1,2 ; 1 National Synchrotron Radiation Research Center, Scientistific Research Division, Hsinchu, Taiwan 2 National Central University, Department of Physics, Taoyuan City, Taiwan alphaA-crystallin and alphaB-crystallin, the water soluble proteins, are able to carry out their chaperone activtiy to maintain the transparency of eye lens. The cataract, induced by light scattering from eye lens clouding, is the major cause of the blindness for the older people. Previous studies show denature of alpha-crystallins cause abnormal aggregation of proteins and consequently lead to eye lens clouding. The mechanism is still a puzzle. Besides protein structure, the interaction between alpha-crystallins and membranes have been considered as possible mechanism of the function loss. In this study, the different thicknesses of lipid membranes composed of Di18:1PC (DOPC) and Di20:1PC are used to be model membranes and interact with alpha-crystallins. The lamellar X-ray diffraction (LXD) was used to probe the structural change of lipid membranes to investigate the effect of hydrophobic match between alpha-crystallins and lipid membranes. ADH and insulin assays were used to monitor the chaperone activity of alpha-crystallins in the presence and absence of lipid membranes. Our result indicates the insertion of alpha-crystallins into lipid membranes decreases their chaperone activity. Furthermore, hydrophobic mismatch between alpha-crystallins and thinner membranes may recover their chaperone activity via suppressing their insertion into membranes. We proposed the inhibition on chaperone activity of alpha-crystallins was mediated by membranes.

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