The formation of oxidatively induced high-molecular-weight aggregate of alpha-/gamma-crystallins.
alpha-/gamma-Crystallin interactions under oxidation with ascorbate-FeCl3-EDTA-H2O2 followed by dialysis have been studied. A high-molecular-weight aggregate (HMWA) composed of alpha- and gamma-crystallin was observed for the mixture of the dialyzed alpha-crystallin and the oxidized gamma-crystallin through gel-filtration chromatography. This illustrates an interaction between alpha-crystallin and partially denatured gamma-crystallin induced by oxidation. No HMWA formation was observed under the condition without dialysis and/or with the addition of catalase to the oxidized gamma-crystallin prior to the addition of alpha-crystallin. More HMWA was formed by oxidized gamma-crystallin followed by the addition of alpha-crystallin than by simultaneous oxidation of both alpha- and gamma-crystallins. Conformational changes of alpha-crystallin during oxidation analyzed by circular dichroism spectra showed that oxidized alpha-crystallin can gradually be restored to an ordered structure through dialysis. The overall results imply that structural changes of both alpha- and gamma-crystallins and dialysis are required to form HMWA. The observation of this oxidatively induced chaperone/substrate complex suggests that an efficient chaperone-like protective action against oxidative insults may exist in vivo.
Huang
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FY
Department of Chemistry, National Cheng Kung University, Tainan, 70101, Taiwan. fhuang@mail.ncku.edu.tw
Chia
C M
CM
Ho
Y
Y
D000818:Animals; D002850:Chromatography, Gel; D002942:Circular Dichroism; D003459:Crystallins / Q000096:biosynthesis* / Q000737:chemistry*; D005260:Female; D007908:Lens, Crystalline / Q000737:chemistry; D011487:Protein Conformation; D051381:Rats; D017207:Rats, Sprague-Dawley
D003459:Crystallins