Age-dependent association of gamma-crystallins with aged alpha-crystallins from old bovine lens.
OBJECTIVE
Previous theoretical and experimental studies have predicted that the loss of weak protein interactions between alpha- and gamma-crystallins could result in a decrease in the transparent properties of the aging lens.


METHODS
alpha-Crystallins were prepared from the nucleus of old bovine lens, and gamma-crystallins were prepared from whole fetal bovine lens or from the nucleus of old bovine lens. The possible interactions of old alpha-crystallins with either old gamma-crystallins or fetal gamma-crystallins were quantitated at equilibrium using microequilibrium dialysis. The amount of each gamma-crystallin species in the "full" versus "empty" chambers was determined by reverse phase chromatography to obtain a binding ratio (full/empty).


RESULTS
A binding ratio greater than 1.00 is indicative of a alpha-crystallin/gamma-crystallin interaction. Within experimental error (+/-2X standard deviation), there were no interactions between aged gamma-crystallins with aged alpha-crystallins while there were significant interactions between some of the fetal gamma-crystallins with aged alpha-crystallins.


CONCLUSIONS
In the aged bovine lens, when transparency is known to decrease, there is no detectable interaction of gamma-crystallins with alpha-crystallins as measured by microequilibrium dialysis. The results are consistent with the hypothesis that short-range, weak, attractive interactions between alpha- and gamma-crystallins are necessary for maximum transparency of the lens.
Takemoto
Larry
L
Division of Biology, Kansas State University, Manhattan, KS, USA. takemlj@ksu.edu
Ponce
Aldo
A
Sorensen
Christopher M
CM
D000375:Aging / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D005333:Fetus / Q000378:metabolism; D007908:Lens, Crystalline / Q000378:metabolism*; D011485:Protein Binding; D038201:alpha-Crystallins / Q000378:metabolism*; D038222:gamma-Crystallins / Q000378:metabolism*
D038201:alpha-Crystallins; D038222:gamma-Crystallins