| one publication added to basket [261275] | Structure of a highly active cephalopod S-crystallin mutant: New molecular evidence for evolution from an active enzyme into lens-refractive protein
Tan, W.-H.; Cheng, S.-C.; Liu, Y.-T.; Wu, C.-G.; Lin, M.-H.; Chen, C.-C.; Lin, C.-H.; Chou, C.-Y. (2016). Structure of a highly active cephalopod S-crystallin mutant: New molecular evidence for evolution from an active enzyme into lens-refractive protein. NPG Scientific Reports 6(31176): 9 pp. http://dx.doi.org/10.1038/srep31176
In: Scientific Reports (Nature Publishing Group). Nature Publishing Group: London. ISSN 2045-2322; e-ISSN 2045-2322, more
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| Authors | | Top |
- Tan, W.-H.
- Cheng, S.-C.
- Liu, Y.-T.
- Wu, C.-G.
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- Lin, M.-H.
- Chen, C.-C.
- Lin, C.-H.
- Chou, C.-Y.
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| Abstract |
Crystallins are found widely in animal lenses and have important functions due to their refractive properties. In the coleoid cephalopods, a lens with a graded refractive index provides good vision and is required for survival. Cephalopod S-crystallin is thought to have evolved from glutathione S-transferase (GST) with various homologs differentially expressed in the lens. However, there is no direct structural information that helps to delineate the mechanisms by which S-crystallin could have evolved. Here we report the structural and biochemical characterization of novel S-crystallin-glutathione complex. The 2.35-A crystal structure of a-crystallin mutant from Octopus vulgaris reveals an active-site architecture that is different from that of GST. S-crystallin has a preference for glutathione binding, although almost lost its GST enzymatic activity. We've also identified four historical mutations that are able to produce a "GST-like" S-crystallin that has regained activity. This protein recapitulates the evolution of S-crystallin from GST. Protein stability studies suggest that S-crystallin is stabilized by glutathione binding to prevent its aggregation; this contrasts with GST-sigma, which do not possess this protection. We suggest that a tradeoff between enzyme activity and the stability of the lens protein might have been one of the major driving force behind lens evolution. |
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