| Abstract: | Abstract: The chaperone activity and biophysical properties of the 19 amino acid peptide DFVIFLDVKHFSPEDLTVK, identified as the functional element in αA‐crystallin and here referred to as mini‐αA‐crystallin, were studied using light scattering and spectroscopic methods after altering its sequence and enantiomerism. The all‐d and all‐l conformers of the peptide do not show marked differences in their chaperone‐like activity against heat‐induced aggregation of alcohol dehydrogenase at 48°C and dithiothreitol‐induced aggregation of insulin. The retro peptide does not show any secondary structure and is also unable to act like a chaperone. Both all‐l and all‐d peptides lose their β‐sheet conformations, hydrophobicity and chaperone‐like activity at temperatures > 50°C. However, upon cooling, a significant portion of those properties was regained, suggesting temperature‐dependent, reversible structural alterations in the peptides under investigation. We propose that both the hydrophobicity and β‐sheet conformation of the functional element of αA‐crystallin are essential for chaperone‐like activity. |
