In vitro cross-linking of calf lens alpha-crystallin by malondialdehyde.
The effect of malondialdehyde on structural features of bovine alpha-crystallin has been investigated by absorption and fluorescence spectroscopy as well as by far-UV circular dichroism. Experimental evidence suggests the occurrence of intermolecular cross-linking induced by malondialdehyde. This cross-linking does not seem to affect the tryptophan environment, as suggested by intrinsic protein fluorescence. On the contrary, the time dependence of far-UV dichroic activity indicates that the cross-linking is accompanied by a secondary structure change. The formation of high molecular mass aggregates, evidence by electrophoresis in denaturing conditions, leads to irreversible alpha-crystallin aggregation due to extensive intermolecular cross-linking. Since malondialdehyde is produced in vivo as a breakdown product of lipid peroxidation the possible involvement of this molecule in the pathological mechanism of cataract formation has been briefly discussed.
Libondi
T
T
Institute of Opthalmology, Faculty of Medicine, 2nd University of Naples, Italy.
Ragone
R
R
Vincenti
D
D
Stiuso
P
P
Auricchio
G
G
Colonna
G
G
D000818:Animals; D002417:Cattle; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002942:Circular Dichroism; D003432:Cross-Linking Reagents / Q000737:chemistry / Q000494:pharmacology; D003459:Crystallins / Q000737:chemistry* / Q000187:drug effects*; D008315:Malondialdehyde / Q000737:chemistry* / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
D003432:Cross-Linking Reagents; D003459:Crystallins; D008315:Malondialdehyde