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Evolution of graded refractive index in squid lenses.

Publication ,  Journal Article
Sweeney, AM; Des Marais, DL; Ban, Y-EA; Johnsen, S
Published in: Journal of the Royal Society, Interface
August 2007

A lens with a graded refractive index is required for vision in aquatic animals with camera-type eyes. This optical design entails a radial gradient of protein density, with low density in external layers and high density in internal layers. To maintain the optical stability of the eye, different material properties are required for proteins in different regions of the lens. In low-density regions of the lens where slight protein aggregation causes significant light scattering, aggregation must be minimized. Squid lens S-crystallin proteins are evolutionarily derived from the glutathione S-transferase protein family. We used biochemistry, optical modelling and phylogenetics to study the evolution and material properties of S-crystallins. S-crystallins are differentially expressed in a radial gradient, suggesting a role in refractive index. This gradient in S-crystallin expression is correlated with their evolutionary history and biochemistry. S-crystallins have been under positive selection. This selection appears to have resulted in stabilization of derived S-crystallins via mutations in the dimer interface and extended electrostatic fields. These derived S-crystallins probably cause the glassy organization and stability of low refractive index lens layers. Our work elucidates the molecular and evolutionary mechanisms underlying the production and maintenance of camera-like optics in squid lenses.

Duke Scholars

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Published In

Journal of the Royal Society, Interface

DOI

EISSN

1742-5662

ISSN

1742-5689

Publication Date

August 2007

Volume

4

Issue

15

Start / End Page

685 / 698

Related Subject Headings

  • Static Electricity
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Refractometry
  • Phylogeny
  • Molecular Sequence Data
  • Lens, Crystalline
  • Glutathione Transferase
  • General Science & Technology
  • Dimerization
  • Decapodiformes
 

Citation

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Sweeney, A. M., Des Marais, D. L., Ban, Y.-E., & Johnsen, S. (2007). Evolution of graded refractive index in squid lenses. Journal of the Royal Society, Interface, 4(15), 685–698. https://doi.org/10.1098/rsif.2006.0210
Sweeney, Alison M., David L. Des Marais, Yih-En Andrew Ban, and Sönke Johnsen. “Evolution of graded refractive index in squid lenses.Journal of the Royal Society, Interface 4, no. 15 (August 2007): 685–98. https://doi.org/10.1098/rsif.2006.0210.
Sweeney AM, Des Marais DL, Ban Y-EA, Johnsen S. Evolution of graded refractive index in squid lenses. Journal of the Royal Society, Interface. 2007 Aug;4(15):685–98.
Sweeney, Alison M., et al. “Evolution of graded refractive index in squid lenses.Journal of the Royal Society, Interface, vol. 4, no. 15, Aug. 2007, pp. 685–98. Epmc, doi:10.1098/rsif.2006.0210.
Sweeney AM, Des Marais DL, Ban Y-EA, Johnsen S. Evolution of graded refractive index in squid lenses. Journal of the Royal Society, Interface. 2007 Aug;4(15):685–698.
Journal cover image

Published In

Journal of the Royal Society, Interface

DOI

EISSN

1742-5662

ISSN

1742-5689

Publication Date

August 2007

Volume

4

Issue

15

Start / End Page

685 / 698

Related Subject Headings

  • Static Electricity
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Refractometry
  • Phylogeny
  • Molecular Sequence Data
  • Lens, Crystalline
  • Glutathione Transferase
  • General Science & Technology
  • Dimerization
  • Decapodiformes