Alpha-crystallin exists in a non-spherical form. A study on the rotational properties of native and reconstituted alpha-crystallin.
Native alpha-crystallin, obtained from the cortex of calf lenses with FPLC (Pharmacia) was characterized by means of transient-electric-birefringence measurements and ultraviolet linear-dichroism spectroscopy. These techniques were also performed on 6-M-urea-dissociated and reconstituted alpha-crystallin. Transient-electric-birefringence measurements offer the possibility to characterize the often observed, but usually neglected, non-spherical occurrences of alpha-crystallin in more detail. Although not distinguishable with size-exclusion chromatography, we could identify at least two different classes of both native and reconstituted alpha-crystallin, from which at least one consists of non-spherical molecules. The results are compared with those obtained with electron microscopy using different staining methods. From the three independent techniques used we find evidence that a fraction of the alpha-crystallin exists in a more extended quaternary structure. The results are difficult to explain with a concentric three-layer model for alpha-crystallin as proposed by Tardieu et al. [Tardieu, A., Laporte, D., Licinio, P., Krop, B. & Delaye, M. (1986) J. Mol. Biol. 192, 711-724].
van Haeringen
B
B
Dept. of Biophysics, Free University, Amsterdam, The Netherlands.
Eden
D
D
van den Bogaerde
M R
MR
van Grondelle
R
R
Bloemendal
M
M
D000818:Animals; D002417:Cattle; D002853:Chromatography, Liquid; D003459:Crystallins / Q000737:chemistry*; D011487:Protein Conformation; D013056:Spectrophotometry, Ultraviolet
D003459:Crystallins