Dataset Information

?A-Crystallin-derived mini-chaperone modulates stability and function of cataract causing ?AG98R-crystallin.

ABSTRACT:

Background

A substitution mutation in human ?A-crystallin (?AG98R) is associated with autosomal dominant cataract. The recombinant mutant ?AG98R protein exhibits altered structure, substrate-dependent chaperone activity, impaired oligomer stability and aggregation on prolonged incubation at 37 °C. Our previous studies have shown that ?A-crystallin-derived mini-chaperone (DFVIFLDVKHFSPEDLTVK) functions like a molecular chaperone by suppressing the aggregation of denaturing proteins. The present study was undertaken to determine the effect of ?A-crystallin-derived mini-chaperone on the stability and chaperone activity of ?AG98R-crystallin.

Methodology/principal findings

Recombinant ?AG98R was incubated in presence and absence of mini-chaperone and analyzed by chromatographic and spectrometric methods. Transmission electron microscope was used to examine the effect of mini-chaperone on the aggregation propensity of mutant protein. Mini-chaperone containing photoactive benzoylphenylalanine was used to confirm the interaction of mini-chaperone with ?AG98R. The rescuing of chaperone activity in mutant?-crystallin (?AG98R) by mini-chaperone was confirmed by chaperone assays. We found that the addition of the mini-chaperone during incubation of ?AG98R protected the mutant crystallin from forming larger aggregates that precipitate with time. The mini-chaperone-stabilized ?AG98R displayed chaperone activity comparable to that of wild-type ?A-crystallin. The complexes formed between mini-?A-?AG98R complex and ADH were more stable than the complexes formed between ?AG98R and ADH. Western-blotting and mass spectrometry confirmed the binding of mini-chaperone to mutant crystallin.

Conclusion/significance

These results demonstrate that mini-chaperone stabilizes the mutant ?A-crystallin and modulates the chaperone activity of ?AG98R. These findings aid in our understanding of how to design peptide chaperones that can be used to stabilize mutant ?A-crystallins and preserve the chaperone function.

SUBMITTER: Raju M

PROVIDER: S-EPMC3435407 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Publications

αA-Crystallin-derived mini-chaperone modulates stability and function of cataract causing αAG98R-crystallin.

Raju Murugesan M Santhoshkumar Puttur P Sharma K Krishna KK

PloS one 20120906 9

<h4>Background</h4>A substitution mutation in human αA-crystallin (αAG98R) is associated with autosomal dominant cataract. The recombinant mutant αAG98R protein exhibits altered structure, substrate-dependent chaperone activity, impaired oligomer stability and aggregation on prolonged incubation at 37 °C. Our previous studies have shown that αA-crystallin-derived mini-chaperone (DFVIFLDVKHFSPEDLTVK) functions like a molecular chaperone by suppressing the aggregation of denaturing proteins. The p ...[more]

PMID: 22970163

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