RESUMEN
The dynamics of concentrated suspensions of the eye-lens protein alpha crystallin have been measured using x-ray photon correlation spectroscopy. Measurements were made at wave vectors corresponding to the first peak in the hard-sphere structure factor and volume fractions close to the critical volume fraction for the glass transition. Langevin dynamics simulations were also performed in parallel to the experiments. The intermediate scattering function f(q,τ) could be fit using a stretched exponential decay for both experiments and numerical simulations. The measured relaxation times show good agreement with simulations for polydisperse hard-sphere colloids.
RESUMEN
Alpha crystallin, a small heat-shock protein, has been studied extensively for its chaperone function. Alpha crystallin subunits are expressed in stress conditions and have been found to prevent apoptosis by inhibiting the activation of caspase pathway. Non-enzymatic glycation of protein leads to the formation of advanced glycation end-products (AGEs). These AGEs bind to receptors and lead to blocking the signaling pathways or cause protein precipitation as observed in aggregation-related diseases. Methylglyoxal (MGO) is one of the major glycating agents expressed in pathological conditions due to defective glycolysis pathway. MGO reacts rapidly with proteins, forms AGEs and finally leads to aggregation. The goal of this study was to understand the non-enzymatic glycation-induced structural damage in alpha crystallin using biophysical and spectroscopic characterization. This will help to develop better disease models for understanding the biochemical pathways and also in drug discovery.