December 2002
Volume 43, Issue 13
ARVO Annual Meeting Abstract  |   December 2002
The Role of Alpha-crystallin in Fiber Cell Dehydration
Author Affiliations & Notes
  • PN Farnsworth
    Pharmacology/Physiology & Ophthalmology
    UMD-New Jersey Medical School Newark NJ
  • PH Frederikse
    Pharmacology/Physiology & Ophthalmology
    UMD-New Jersey Medical School Newark NJ
  • K Singh
    Biochemistry and Molecular Biology
    UMD-New Jersey Medical School Newark NJ
  • Footnotes
    Commercial Relationships   P.N. Farnsworth, None; P.H. Frederikse, None; K. Singh, None. Grant Identification: Research to Prevent Blindness
Investigative Ophthalmology & Visual Science December 2002, Vol.43, 3555. doi:
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    • Get Citation

      PN Farnsworth, PH Frederikse, K Singh; The Role of Alpha-crystallin in Fiber Cell Dehydration . Invest. Ophthalmol. Vis. Sci. 2002;43(13):3555.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract: : Purpose:To investigate the structural and functional significance of the self-complementary motifs (SCM) in α-crystallin subunits, αA and αB. Methods: Several computational biochemical programs such as Sybyl for molecular modeling and GCG for sequence comparisons were used to identify other proteins with SCM and to correlate their structure/function relationship with α-crystallin subunits. These data were also corrrelated with published and new experimental results. Results: SCM within insulin (B21-29) and Aß (14-23) share both homology and ß sheet secondary structure with the SCM1 of the more lens specific αA (Farnsworth and Singh, 2000}. Interaction of the SCM in reverse order of Aß and insulin form pseudo ß sheets required for the nucleation of amyloid protein structure. This plus the stacking of true ß sheets form the core of amyloid structure. The pseudo ß sheets provide the binding sites for the amyloid stains, Congo red and thioflavin T. α-Crystallin also binds these stains.The formation of amyloid structure is accompanied by the rapid extrusion of water and significant protein dehydration. Conclusion: These observations provide a chemical and physiological basis for the lens fiber cell dehydration that occurs precisely where amyloid staining begins in cortical fibers (Frederikse, 2000). This also correlates with a precipitous increase in protein concentration and an altered crystallin supramolecular order, our proposed protein phase transition zone (Gagna et al., 1997). The stability and the resistance to perturbation by denaturants and proteolysis of amyloid-like dehydrated ß sheet structure may contribute to the long term maintenance of lens transparency.

Keywords: 364 computational modeling • 378 crystallins • 527 protein structure/function 

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