Abstract
Abstract: :
Purpose:To investigate whether residues 73-92 in alpha B-crystallin, homologous to alpha A-crystallin chaperone site and mini-alpha A-crystallin can also function as mini-alpha B-crystallin with chaperone-like activity. Methods:Peptide, DRFSVNLDVKHFSPEELKVK, (residues 73-92 of alpha B-crystallin) and its truncated forms as well as Ala derivatives were synthesized by solid phase synthetic approach. Bis-ANS binding studies, CD spectroscopy and chaperone assays were used to characterize the peptides. Results:The CD spectral analysis of the peptides revealed that the chaperone peptide has significant beta sheet structure at room temperature. During insulin reduction assay as well as thermal denaturation assays with alcoholdehydrogenase and citratesynthase the synthetic peptide dispalyed chaperone-like activity of the parent protein-alpha B-crystallin. The activity of the peptide was comparable to the activity of mini-alpha A-crystallin reported earlier. Truncated peptides and peptides with Ala substitutions showed significant loss in the chaperone-like activity. Conclusion:These results confirm that the highly conserved 73-92 region in alpha B-crystallin is the chaperone site.
Keywords: 343 chaperones • 378 crystallins • 527 protein structure/function