Abstract

Alpha-crystallin, tha major protein component of the crystalline lens of mammalian eyes , exist in the lens cytoplasm as aggregates of approximately 40 subunits in an isoform mixture of 3A:1B in the human. Because of the way the lens develops throughout the lifetime of an organism, a-crystallin and other lens proteins must (a) be stable in structure and resistant to denaturation for a period of years or decades; (b) must be present without superaggregation in sufficient quantities to raise significantly the refractive index of the lens; and (c) must be small and discrete enough to enable lens transparency in the visible light spectrum. The recent discovery by Horwitz that a-crystallin is related in sequence to the heat shock protein family and that it can act in a chaperone-line fashion to prevent the superaggregation of partially denatured proteins may explain why it was """"""""recruited"""""""" as a lens protein. It is present in all the major non-lenticular tissues, but only in the lens are the two isoforms of a-crystallin found together. The long-term objective of this research is therefore to characterize the unique structural and functional properties of a-crystallin that contribute to long-term visual function and work against cataractogenesis. In the next grant period, the specific aims are (a) to investigate comparatively the structural and functional properties of native, reconstituted, and renatured a-crystallin aggregates in order to characterize the basis for their long-term stability; and (b) to compare the structural and functional properties of the a -crystallin isoforms in order to understand why it is only in the lens that both are found together. A variety of biophysical and physical biochemical techniques will be employed for this work, including circular dichroism spectropolarimetry to study secondary structure, fast performance liquid chromatography, fluorescence energy transfer, synchrotron scattering and diffraction, electron microscopy, and rheometry.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY010011-06
Application #
6164677
Study Section
Visual Sciences A Study Section (VISA)
Program Officer
Liberman, Ellen S
Project Start
1994-06-01
Project End
2002-02-28
Budget Start
2000-03-01
Budget End
2001-02-28
Support Year
6
Fiscal Year
2000
Total Cost
$256,949
Indirect Cost

  Institution

Name
Rensselaer Polytechnic Institute
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
002430742
City
Troy
State
NY
Country
United States
Zip Code
12180

  Publications

Li, Ying; Schmitz, Karl R; Salerno, John C et al. (2007) The role of the conserved COOH-terminal triad in alphaA-crystallin aggregation and functionality. Mol Vis 13:1758-68
Yang, Chaoxing; Salerno, John C; Koretz, Jane F (2005) NH2-terminal stabilization of small heat shock protein structure: a comparison of two NH2-terminal deletion mutants of alphaA-crystallin. Mol Vis 11:641-7
Eifert, Cheryl; Burgio, Michael R; Bennett, Pauline M et al. (2005) N-terminal control of small heat shock protein oligomerization: changes in aggregate size and chaperone-like function. Biochim Biophys Acta 1748:146-56
Regini, J W; Grossmann, J G; Burgio, M R et al. (2004) Structural changes in alpha-crystallin and whole eye lens during heating, observed by low-angle X-ray diffraction. J Mol Biol 336:1185-94
Salerno, John C; Eifert, Cheryl L; Salerno, Kathleen M et al. (2003) Structural diversity in the small heat shock protein superfamily: control of aggregation by the N-terminal region. Protein Eng 16:847-51
Desai, Prashant; Prachand, Mamta; Coutinho, Evans et al. (2002) Activity and conformation of a cyclic heptapeptide possessing the message sequence His-Phe-Arg-Trp of alpha-melanotropin. Int J Biol Macromol 30:187-95
Burgio, M R; Bennett, P M; Koretz, J F (2001) Heat-induced quaternary transitions in hetero- and homo-polymers of alpha-crystallin. Mol Vis 7:228-33
Burgio, M R; Kim, C J; Dow, C C et al. (2000) Correlation between the chaperone-like activity and aggregate size of alpha-crystallin with increasing temperature. Biochem Biophys Res Commun 268:426-32
Koretz, J F; Doss, E W; LaButti, J N (1998) Environmental factors influencing the chaperone-like activity of alpha-crystallin. Int J Biol Macromol 22:283-94
Doss-Pepe, E W; Carew, E L; Koretz, J F (1998) Studies of the denaturation patterns of bovine alpha-crystallin using an ionic denaturant, guanidine hydrochloride and a non-ionic denaturant, urea. Exp Eye Res 67:657-79

Showing the most recent 10 out of 13 publications