Heat-induced structural transitions of alpha-crystallin studied by small-angle neutron scattering

• Published in: Journal of physics. Conference series 2012-01, Vol.351 (1), p.12008-8
• Main Authors: Krivandin, A V, Kuklin, A I, Muranov, K O, Murugova, T N, Kozlov, S S, Genkina, N K
• Format: Article
• Language: English
• Subjects: Alpha rays; Buffer solutions; Calorimetry; Computer programs; Cooling; Crystal structure; Crystallinity; High temperature; Mathematical models; Molecular structure; Neutron scattering; Neutrons; Oligomers; Physics; Styrene acrylonitrile resins; Transformations
• ISSN: 1742-6596; 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/351/1/012008

Alpha-crystallin from the bovine eye lens was studied by small-angle neutron scattering (SANS) in 90% D2O buffer solution at 20, 50, 60, 65, 75, 85 and 95°C. The temperature points for this study were specified on the basis of differential scanning calorimetric analysis of alpha-crystallin solutions which has shown two endothermic transitions with midpoints at 64.5 and 86°C. The SANS study revealed no significant alpha-crystallin quaternary structure alterations at 50°C as compared with 20°C. At 60-65°C the SANS data confirmed substantial alpha-crystallin quaternary structure rearrangements which resulted in the formation of alpha-crystallin oligomers with a similar shape but approximately twofold increased molecular weight as compared to the native state at 20°C. At higher temperatures (75, 85 and 95°C) the SANS patterns were very similar and were consistent with the scattering by rod-like particles with a cross-section radius of gyration ∼55 This transformation of alpha-crystallin to the rod-like particles was evidently irreversible as these particles remained in solution after cooling to 20°C. Ab initio shape models of the native and high-temperature alpha-crystallin were retrieved with DAMMIN and DAMAVER software. Schematic model of alpha-crystallin heat-induced quaternary structure transitions was considered.